The electric discharge machining (EDM) is one of the most up-to-date non-traditional machining pr... more The electric discharge machining (EDM) is one of the most up-to-date non-traditional machining processes, based on thermo-electric energy between the work piece and an electrode (tool). In this machining method, the material is removed electro thermally by a series of consecutive separate discharges between two electrically conductive materials (electrode and work piece). The performance of the machining process depends on the material, design and manufacturing method of the electrodes. Generally, the machine maker uses the average work piece and electrode materials to establish the EDM parameter settings. The current study paying attention on the effect of Copper and Brass tools on material removal rate (MRR) for AISI (American Iron Steel Institute) D2 tool steel by using DieSinker EDM. The current was varied from 4 to 10 amp, the electrical voltage and flushing pressure were constant, the MRR for copper electrode was in the range of 4.8923 -21.9580 mm/min whereas the range of MRR ...
Linear programming (L.P) method is applied to optimize energy consumption within an organization.... more Linear programming (L.P) method is applied to optimize energy consumption within an organization. Three parameters are chosen for energy conservation, namely changing of normal window to double glazed or triple glazed window, installation of Solar Panels, replacing of Fluorescent tube lights with LED tube lights. Optimize use of these parameters will results in saving of good amount of energy which will save our money. The cost for various equipment such as compact fluorescent light bulbs, LED bulbs, double glazed and triple glazed window and solar panels are taken from manufacturer website. The project provides the optimized solution for three ranges of budgets viz. Low, Medium and high. The project also provides the recovery period or payback period for the investment being done.
In this era of mass manufacturing MRR (material removal rate) is of prime concern even in manufac... more In this era of mass manufacturing MRR (material removal rate) is of prime concern even in manufacturing using CNC machines. The main objective of today's modern manufacturing industries is to produce low cost and high quality product in short time. In order to improve the quality and to reduce the cost material removal rate should be optimum. In machining accurate dimensions is desired but with good product quality. Machining process involves many factors which affects the process directly or indirectly. The research study aims to analyze MRR by taking feed, depth of cut &spindle speed into consideration of Aluminum 6063 employing Taguchi method. A L9 Orthogonal array is used to performing the various experimental studies that analysis the MMR and analysis of surface roughness and signal to Noise Ratio (S/N ratio).
The electric discharge machining (EDM) is one of the most up-to-date non-traditional machining pr... more The electric discharge machining (EDM) is one of the most up-to-date non-traditional machining processes, based on thermo-electric energy between the work piece and an electrode (tool). In this machining method, the material is removed electro thermally by a series of consecutive separate discharges between two electrically conductive materials (electrode and work piece). The performance of the machining process depends on the material, design and manufacturing method of the electrodes. Generally, the machine maker uses the average work piece and electrode materials to establish the EDM parameter settings. The current study paying attention on the effect of Copper and Brass tools on material removal rate (MRR) for AISI (American Iron Steel Institute) D2 tool steel by using Die-Sinker EDM. The current was varied from 4 to 10 amp, the electrical voltage and flushing pressure were constant, the MRR for copper electrode was in the range of 4.8923-21.9580 mm 3 /min whereas the range of MRR for brass electrode was 8.0013-9.7903 mm 3 /min. The MRR for copper electrode was continuously decreasing with voltage whereas MRR for brass follow a definite development. The MRR for both the electrodes increases with current. It has been observed that copper electrode is the best for machining AISI D2 tool steel by using Die-Sinker EDM for large material removal rate.
In this paper, walnut shell particle and coconut fibre are developed. The suitability of walnut p... more In this paper, walnut shell particle and coconut fibre are developed. The suitability of walnut particle and coconut fibre as a biocomposite reinforcing material was investigated. 20 wt% of walnut shell particle of size 1.618 m µ-2.685 m µ and 10 wt% of coconut fibre of length 2-3 mm were mixed in epoxy CY 230 resin for preparation of hybrid biocomposite. The tensile properties and flexural test of hybrid biocomposite reinforced with walnut shell particle and coconut fibre were evaluated and analysed. Scanning electro microscopy was employed to characterize the tensile properties and fracture behaviour of biocomposite. The results show that ultimate strength, modulus of elasticity and yield strength of biocomposite material are about 54.3%, 86.4% and 88.3% of pure epoxy resin respectively. The compressive ultimate strength of biocomposite is 44.45 MPa as compared to 55.16 MPa of epoxy resin. This results reveals that the addition of 20 wt% walnut particles and 10 wt% coconut fibres yield better ultimate strength with approximately 80.58% of pure epoxy. The flexural modulus of biocomposite is 1706.15 MPa which is about 86.3% of pure epoxy. The flexural strength of biocomposite is 34.04 MPa which is about 35.7% of pure epoxy.
The purpose of this work is to study, bullwhip effect on supply chain management and discuss the ... more The purpose of this work is to study, bullwhip effect on supply chain management and discuss the develop a conceptual model on the potential barriers in the implementation of supply chain flexibility in small-scale industries. The model suggests that supply chain flexibility can be researched using a three-tier approach: identification of risks, identification of potential barriers emerging from these risks, identification of bridges to these barriers. The proposed is based on the view of problems of small-scale industries as well as the limited research on supply chain flexibility. The studies indicated that the three main barriers to flexibility in supply chains are improper integration between systems, Supply Chain Function cost and quickening pace of product innovation. Some ways to overcome these barriers and act as bridges are also summarized. The field of study of supply chain flexibility presents numerous options for fresh research work.
The artificial roughness on the heated surface of solar air heater is an cost effective and econo... more The artificial roughness on the heated surface of solar air heater is an cost effective and economical way to significantly enhance the heat transfer rate. There are several roughness geometries provides in different forms such as ribs, wire mesh, baffles etc. which is used to enhance the heat transfer from the surface of the solar air heater. Experimental investigation shows that artificial roughness can give essential enhancement in heat transfer rate which improves the thermal performance of solar air heater. It has been observed that with the use of jet impingement on the base plate three times higher heat transfer coefficient is achieved due to highly turbulent impingement boundary layers. It is required to understand how the flow is been affected with the use of different roughness geometries in the form of repeated ribs with jet impingements.
Thermodynamic analysis of N 2 O transcritical refrigeration cycle using dedicated mechanical subc... more Thermodynamic analysis of N 2 O transcritical refrigeration cycle using dedicated mechanical subcooling cycle has been carried out in the present work. The transcritical cycle with the mechanical subcooling is evaluated for three different evaporator temperatures 5,-5 and-30ºC with different degrees of subcooling and for the environment temperatures range from 20 to 40 ºC using propane as refrigerant for the subcooling cycle. Performance of N 2 O transcritical cycle has been compared with CO 2 transcritical cycle. The results show that N 2 O transcritical cycle is better than CO 2 transcritical cycle for environment temperature above 25°C, which is an important fact for countries having tropical climate. It has been found that using combined cycle, the maximum increments in COP and in specific cooling capacity are 22% and 30% respectively. It has also been found that using mechanical subcooling cycle, the reduction in optimum heat rejection pressure is higher for lower evaporator temperature i.e.-30 °C and power consumption ratio is higher for higher evaporator temperature i.e. 5 °C. Further, the increment in COP using different refrigerants in mechanical subcooling cycle has been presented, where no significant differences have been found. The increment indicates that this cycle is more efficient for the environment temperatures above 30 °C.
Over the past few decades each and every organization, be it an industry for production, a unit o... more Over the past few decades each and every organization, be it an industry for production, a unit of manufacturing, a government organization, a limited corporation, a banking sector or an educational institution is focusing on increasing profit margin. And in order to do that, one of the key factors is achieving maximum output with minimum resources (input). Therefore, it has become extremely important for organizations to plan the use of resources in the most optimum way.
—The suitability of walnut particle and coconut fibre as a biocomposite reinforcing material was ... more —The suitability of walnut particle and coconut fibre as a biocomposite reinforcing material was investigated. 20 wt% of walnut shell particle of size 1.618 m µ-2.685 m µ and 10 wt% of coconut fibre of length 2-3 mm were mixed in epoxy CY 230 resin for preparation of hybrid biocomposite. The tensile properties and flexural test of hybrid biocomposite reinforced with walnut shell particle and coconut fibre were evaluated and analysed. Scanning electro microscopy was employed to characterize the tensile properties and fracture behaviour of biocomposite. The results show that ultimate strength, modulus of elasticity and yield strength of biocomposite material are about 54.3%, 86.4% and 88.3% of pure epoxy resin respectively. The compressive ultimate strength of biocomposite is 44.45 MPa as compared to 55.16 MPa of epoxy resin. This results reveals that the addition of 20 wt% walnut particles and 10 wt% coconut fibres yield better ultimate strength with approximately 80.58% of pure epoxy. The flexural modulus of biocomposite is 1706.15 MPa which is about 86.3% of pure epoxy. The flexural strength of biocomposite is 34.04 MPa which is about 35.7% of pure epoxy.
The present investigation has been under taken keeping in mind some of the problems concerning th... more The present investigation has been under taken keeping in mind some of the problems concerning the crack propagation direction and growth under constant amplitude load in an inclined crack geometry. The present studies mainly focus on to develop and modified the crack growth criterion to account of the effect of biaxial factor, shearing loading and number of stress terms for different criterion. The effect of one, two and three solution on crack initiation angle determined on the basis of DET-criterion & MTS-criterion. It is seen that difference in crack initiation angle (α) obtained from two and three term solution of DET-criterion & MTS-criterion is significant and higher than one term solution. The comparisons of predicted result obtain from using DET-criterion and MTS-criterion has been made. When comparison is made between two terms solution, it is found that growth rate is higher in case of DET-criterion than MTS-criterion when α <45 0 , whereas fatigue growth rate obtain by MTS-criterion is found to be the higher than the DET-criterion for α >45 0. It is observed that only three terms are sufficient to determine the stress and displacement field ahead of the crack tip. Variation of crack initiation angle with crack angle for different biaxial load factor and shear load factor by DET-criterion and MTS-criterion for three term solution is compared. The crack initiation angle also depends upon biaxial factor and shear load factor. NOTATIONS: β = crack inclination angle 0 β = crack initiation angle 2a = Initial crack length r and θ = polar coordinate of crack tip II I K K , = mode I and mode II stress intensity factor xy y x τ σ σ , , = stress components b 1 = Biaxial factor b 2 = Shear or torsional load factor INTRODUCTION: Fracture mechanics has been established as an important principle dealing with the growth of fatigue crack. During recent years, the fracture mechanics has obtained a considerable importance for studding the crack growth behavior under static and fatigue loading. The majority of the research done in the area of fracture mechanics was accomplished in the opening mode only. Hence the practical application of the fracture mechanics is limited. The mixed mode crack growth problem has drawn comparably little attention, but is actually more realistic and possibly more dangerous than mode-I crack. The mixed mode growth occurs when a fatigue crack is nucleated along the inclusions or welded defects located making an angle with the axis of the applied load. The fatigue crack growth under multi axial stress is to be considering as mixed mode. The mixed mode cracks generally propagate in a non-self similar manner. Hence, in case of mixed mode loading condition, the study of the crack initiation angle and crack growth rate is of equal importance. A considerable amount of the work has been done to define governing mixed mode loading and crack growth behavior. Papadopoulos (1987) proposed the DET-criterion is based on determinants of the stress tensor. Using the stress as parameter, MTS-criterion proposed by Erdigan & Sih (1963) is based on the
Fracture mechanics has been established as an important principle dealing with the growth of fati... more Fracture mechanics has been established as an important principle dealing with the growth of fatigue crack. During recent years, the fracture mechanics has obtained a considerable importance for studding the crack growth behavior under static and fatigue loading. The largest number of in-service failures results from the scenario involving fluctuating, cyclic or repeated loading, usually combination with static load. Typically, a defect located near a stress raiser enlarges under repeated tensile stresses into a crack that continues to grow stably a small amount during each load cycle until the crack either penetrates the structure or attains critical length, after which unstable crack propagation occurs. The present investigation has been under taken keeping in mind some of the problems concerning the crack propagation direction and growth under constant amplitude load in an inclined crack geometry. The present studies mainly focus on to develop and modified the crack growth criterion to account of the effect of biaxial factor, shearing loading and number of stress terms for different criterion. The effect of one, two and three solution on crack initiation angle determined on the basis of DET-criterion & MTS criterion. 1.0 Introduction The majority of the research done in the area of fracture mechanics was accomplished in the opening mode only. Hence the practical application of the fracture mechanics is limited. The mixed mode crack growth problem has drawn comparably little attention, but is actually more realistic and possibly more dangerous than mode-I crack. The mixed mode growth occurs when a fatigue crack is nucleated along the inclusions or welded defects located making an angle with the axis of the applied load. The fatigue crack growth under multi axial stress is to be considering as mixed mode. The mixed mode cracks generally propagate in a non-self similar manner. Hence, in case of mixed mode loading condition, the study of the crack initiation angle and crack growth rate is of equal importance. The predictions of mixed mode crack growth direction, different criterion have been proposed. Using the stress as parameter, MTS-criterion proposed by Erdigan & Sih (1963) is based on the assumption that the material behaves ideally brittle. This assumption is not supported by all kind of material. SED-criterion of Sih (1974) is based on the minimum strain energy density principle. This criterion corresponds to maximum potential energy, which is regarded as the integral of field variable over some domain rather than a point and is insensitive to sign of the loading. T-criterion proposed by Theocaries et. al. (1982) is also based on the SED-criterion, which is modified by using a variable radius for core region. Papadopoulos (1987) proposed the DET-criterion is based on determinants of the stress tensor. The predicted crack initiation angles by DET-criterion are found to be much higher relative to the one obtained by the MTS or the SED criterion. The theoretical results obtained for different loading cases are shown and discussed by Khan et. al. (2000). They have shown that the result for MTS-criterion and T-criterion match exactly for all loading cases, although both have been derived on different theoretical basis. Prais (1963) co-relate the rate of crack growth to the stress intensity factor for simple opening (mode-I). Robert and Kibla (1971) indicated in their result that the fatigue crack under mixed loading grew in a manner which did not reduce the mode-II component of load to zero and that the growth rate was accelerating by mode-II components of the stress applied simultaneously. A considerable amount of the work has been done to define governing mixed mode loading and crack growth behavior.
The suitability of walnut particle and coconut fiber as a biocomposite reinforcing material was i... more The suitability of walnut particle and coconut fiber as a biocomposite reinforcing material was investigated. 20 wt% of walnut shell particles of size 1.618-2.685 and 10 wt% of coconut fibre of length 2-3 mm were mixed with epoxy CY 230 resin for preparation of hybrid biocomposite. The tensile properties and flexural test of hybrid biocomposite reinforced with walnut shell particle and coconut fiber were evaluated and analyzed. Scanning electron microscopy was employed to characterize the tensile properties and fracture behavior of biocomposite. The results show that ultimate strength, modulus of elasticity and yield strength of biocomposite material are about 54.3%, 86.4% and 88.3% of pure epoxy resin respectively. The flexural modulus of biocomposite is 1706.15 MPa which is about 86.3% of pure epoxy. The flexural strength of biocomposite is 34.04 MPa which is about 35.7% of pure epoxy.
In the current scenario where we are using 3G and 4G technologies for communication purposes the ... more In the current scenario where we are using 3G and 4G technologies for communication purposes the Mobile Ad Hoc Networks (MANETs) are generating a lot of interests. The next generation of mobile communications will include both prominent infrastructure wireless networks (3G, 4G) and novel mobile ad hoc networks. It is a collection of portable wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure. This allows portable mobile devices to establish a communication path without having any central infrastructure. Since there is no centralized infrastructure in the MANET and the mobile devices are moving randomly, they may give rise to various kinds of problems, such as energy efficient and multicast congestion control. This paper describes the primary problems of ad hoc networking by giving its related research background. Some of the technical challenges it poses are also presented, based on which the paper points out some of the key research issues for ad hoc networking technology that are expected to promote the development and accelerate the commercial applications of the MANET technology. Special attention is paid on network layer routing strategy and key research issues include new X-cast routing algorithms, security & reliability schemes, QoS model, and mechanisms for interworking with outside IP networks. INTRODUCTION: A mobile ad-hoc network (MANET) is composed of portable or mobile nodes without any infrastructure. Mobile nodes are self-organized to form a network over radio links. The goal of MANETs is to extend mobility into the realm of autonomous, mobile and wireless domains, where a set of nodes from the network by using some kind of the routing infrastructure in an ad-hoc fashion. The majority of applications of MANETs are in areas where fast and dynamic reconfiguration is necessary and wired network is not available. The mobile ad-hoc network is such a network which does not require any infrastructure like traditional wireless network. Initially, it can be useful for the smaller areas like with the computer lab, homes (For communicating with digital cameras, cooking ovens, washing machines, refrigerators, vacuum cleaners and thermostats), the classrooms, etc. But later on after it was successfully implemented and used in these small areas then there is tremendous scope of ad-hoc network. It can be used in military battlefields, emergency search, rescue sites, where participants share information dynamically using their mobile devices. These applications lend themselves well to multicast operations In the last decade, advancement in both hardware and software techniques have resulted in mobile hosts and wireless networking. We can categories mobile wireless communication in two distinct approaches: 1. With Infrastructure. The current or traditional wireless mobile network requires good infrastructure support on the cellular concept in which mobile devices communicate with other mobile devices with base stations connected to the fixed network infrastructure. Typical examples of this kind of wireless networks are GSM, UMTS, WLL, WLAN, etc.
The effect of bio-fibres and bio-particles on the fracture toughness has been investigated. Epoxy... more The effect of bio-fibres and bio-particles on the fracture toughness has been investigated. Epoxy resin is used as matrix material and different bio-fibers such as banana fiber, bagasse fiber, coconut fiber and particles such as silica and walnut shell particle with different wt% are added as reinforcing material. The mode I fracture toughness tests are conducted in a servo hydraulic universal testing machine. The results show that the fracture toughness of bio-composites reinforced with 20wt% bagasse or 10wt% coconut fiber are 1.108MPa and 1.094MPa , respectively which are about 8% and 7% higher than neat epoxy. Addition of 2 wt% of silica with 20 wt% of bagasse shows 60% increment of fracture toughness with respect to bagasse and 72% increment with respect to neat epoxy. Hybridisation of bagasse with banana fibers shows 54% decrease in fracture toughness as compared to bagasse and 13% increase as compared to banana. The overall fracture toughness of hybrid bio-composite of 10 wt% coconut fiber and 20 wt% of walnut shell particle is 1.367MPa which is about 25% higher than coconut fiber reinforced bio-composite.
Mixed-mode fracture characteristics of epoxy-based biocomposite reinforced with
20 wt% walnut she... more Mixed-mode fracture characteristics of epoxy-based biocomposite reinforced with 20 wt% walnut shell particle and 10 wt% coconut fibres are investigated. The biocomposite is fabricated using the squeeze casting method. The positive aspect of hybrid combination of fibre and particle reinforcement is advocated by comparing I, mode II and mixed-mode I/II fracture surfaces under a scanning electron microscope. An edgecracked semicircular arc specimen subjected to symmetric three-point bend (TPB) loading is suggested for fracture toughness testing of biocomposite material. A series of fracture tests are conducted on hybrid biocomposite using the proposed semicircular bend (SCAB) specimen geometry, TPB and four-point bend (FPB) specimens. The average mode I and II fracture toughness obtained from semicircular arc bend (SCAB) specimen are 1.319 MPa and 1.219 MPa ffiffiffiffi m p , respectively. The average values of modes I and II toughness obtained from TPB and FPB specimens are 1.267 and 0.754 MPa ffiffiffiffi m p . The overall ratio of mode I and mode II fracture toughness is found to be 0.762, which is very close to the predicted value of 0.87 by maximum tangential stress criterion. The results obtained from new SCAB geometry are validated with the results obtained from TPB and FPB specimen geometries by statistical significance test. Very good agreement is found between the experimental results obtained from TPB, FPB and the proposed SCAB specimens.
The rectangular specimens with an edge crack were
subjected to symmetric three-point bending and ... more The rectangular specimens with an edge crack were subjected to symmetric three-point bending and asymmetric four-point bending to determine the mode I and mode II fracture toughness of the walnut particle and coconut fiber-reinforced biocomposite. Epoxy resin was used as matrix material and 10 wt% of coconut fiber and 20 wt% of walnut shell particle were used as reinforcing materials. The mode I and mode II fracture toughness and mechanical tests were conducted on a servo hydraulic universal testing machine and the results were analyzed and discussed. POLYM. COMPOS., 36:167–173, 2015. VC 2014 Society of Plastics Engineers
Mixed-mode fracture characteristics of epoxy-based biocomposite reinforced with
20 wt% walnut she... more Mixed-mode fracture characteristics of epoxy-based biocomposite reinforced with 20 wt% walnut shell particle and 10 wt% coconut fibres are investigated. The biocomposite is fabricated using the squeeze casting method. The positive aspect of hybrid combination of fibre and particle reinforcement is advocated by comparing I, mode II and mixed-mode I/II fracture surfaces under a scanning electron microscope. An edgecracked semicircular arc specimen subjected to symmetric three-point bend (TPB) loading is suggested for fracture toughness testing of biocomposite material. A series of fracture tests are conducted on hybrid biocomposite using the proposed semicircular bend (SCAB) specimen geometry, TPB and four-point bend (FPB) specimens. The average mode I and II fracture toughness obtained from semicircular arc bend (SCAB) specimen are 1.319 MPa and 1.219 MPa ffiffiffiffi m p , respectively. The average values of modes I and II toughness obtained from TPB and FPB specimens are 1.267 and 0.754 MPa ffiffiffiffi m p . The overall ratio of mode I and mode II fracture toughness is found to be 0.762, which is very close to the predicted value of 0.87 by maximum tangential stress criterion. The results obtained from new SCAB geometry are validated with the results obtained from TPB and FPB specimen geometries by statistical significance test. Very good agreement is found between the experimental results obtained from TPB, FPB and the proposed SCAB specimens.
The electric discharge machining (EDM) is one of the most up-to-date non-traditional machining pr... more The electric discharge machining (EDM) is one of the most up-to-date non-traditional machining processes, based on thermo-electric energy between the work piece and an electrode (tool). In this machining method, the material is removed electro thermally by a series of consecutive separate discharges between two electrically conductive materials (electrode and work piece). The performance of the machining process depends on the material, design and manufacturing method of the electrodes. Generally, the machine maker uses the average work piece and electrode materials to establish the EDM parameter settings. The current study paying attention on the effect of Copper and Brass tools on material removal rate (MRR) for AISI (American Iron Steel Institute) D2 tool steel by using DieSinker EDM. The current was varied from 4 to 10 amp, the electrical voltage and flushing pressure were constant, the MRR for copper electrode was in the range of 4.8923 -21.9580 mm/min whereas the range of MRR ...
Linear programming (L.P) method is applied to optimize energy consumption within an organization.... more Linear programming (L.P) method is applied to optimize energy consumption within an organization. Three parameters are chosen for energy conservation, namely changing of normal window to double glazed or triple glazed window, installation of Solar Panels, replacing of Fluorescent tube lights with LED tube lights. Optimize use of these parameters will results in saving of good amount of energy which will save our money. The cost for various equipment such as compact fluorescent light bulbs, LED bulbs, double glazed and triple glazed window and solar panels are taken from manufacturer website. The project provides the optimized solution for three ranges of budgets viz. Low, Medium and high. The project also provides the recovery period or payback period for the investment being done.
In this era of mass manufacturing MRR (material removal rate) is of prime concern even in manufac... more In this era of mass manufacturing MRR (material removal rate) is of prime concern even in manufacturing using CNC machines. The main objective of today's modern manufacturing industries is to produce low cost and high quality product in short time. In order to improve the quality and to reduce the cost material removal rate should be optimum. In machining accurate dimensions is desired but with good product quality. Machining process involves many factors which affects the process directly or indirectly. The research study aims to analyze MRR by taking feed, depth of cut &spindle speed into consideration of Aluminum 6063 employing Taguchi method. A L9 Orthogonal array is used to performing the various experimental studies that analysis the MMR and analysis of surface roughness and signal to Noise Ratio (S/N ratio).
The electric discharge machining (EDM) is one of the most up-to-date non-traditional machining pr... more The electric discharge machining (EDM) is one of the most up-to-date non-traditional machining processes, based on thermo-electric energy between the work piece and an electrode (tool). In this machining method, the material is removed electro thermally by a series of consecutive separate discharges between two electrically conductive materials (electrode and work piece). The performance of the machining process depends on the material, design and manufacturing method of the electrodes. Generally, the machine maker uses the average work piece and electrode materials to establish the EDM parameter settings. The current study paying attention on the effect of Copper and Brass tools on material removal rate (MRR) for AISI (American Iron Steel Institute) D2 tool steel by using Die-Sinker EDM. The current was varied from 4 to 10 amp, the electrical voltage and flushing pressure were constant, the MRR for copper electrode was in the range of 4.8923-21.9580 mm 3 /min whereas the range of MRR for brass electrode was 8.0013-9.7903 mm 3 /min. The MRR for copper electrode was continuously decreasing with voltage whereas MRR for brass follow a definite development. The MRR for both the electrodes increases with current. It has been observed that copper electrode is the best for machining AISI D2 tool steel by using Die-Sinker EDM for large material removal rate.
In this paper, walnut shell particle and coconut fibre are developed. The suitability of walnut p... more In this paper, walnut shell particle and coconut fibre are developed. The suitability of walnut particle and coconut fibre as a biocomposite reinforcing material was investigated. 20 wt% of walnut shell particle of size 1.618 m µ-2.685 m µ and 10 wt% of coconut fibre of length 2-3 mm were mixed in epoxy CY 230 resin for preparation of hybrid biocomposite. The tensile properties and flexural test of hybrid biocomposite reinforced with walnut shell particle and coconut fibre were evaluated and analysed. Scanning electro microscopy was employed to characterize the tensile properties and fracture behaviour of biocomposite. The results show that ultimate strength, modulus of elasticity and yield strength of biocomposite material are about 54.3%, 86.4% and 88.3% of pure epoxy resin respectively. The compressive ultimate strength of biocomposite is 44.45 MPa as compared to 55.16 MPa of epoxy resin. This results reveals that the addition of 20 wt% walnut particles and 10 wt% coconut fibres yield better ultimate strength with approximately 80.58% of pure epoxy. The flexural modulus of biocomposite is 1706.15 MPa which is about 86.3% of pure epoxy. The flexural strength of biocomposite is 34.04 MPa which is about 35.7% of pure epoxy.
The purpose of this work is to study, bullwhip effect on supply chain management and discuss the ... more The purpose of this work is to study, bullwhip effect on supply chain management and discuss the develop a conceptual model on the potential barriers in the implementation of supply chain flexibility in small-scale industries. The model suggests that supply chain flexibility can be researched using a three-tier approach: identification of risks, identification of potential barriers emerging from these risks, identification of bridges to these barriers. The proposed is based on the view of problems of small-scale industries as well as the limited research on supply chain flexibility. The studies indicated that the three main barriers to flexibility in supply chains are improper integration between systems, Supply Chain Function cost and quickening pace of product innovation. Some ways to overcome these barriers and act as bridges are also summarized. The field of study of supply chain flexibility presents numerous options for fresh research work.
The artificial roughness on the heated surface of solar air heater is an cost effective and econo... more The artificial roughness on the heated surface of solar air heater is an cost effective and economical way to significantly enhance the heat transfer rate. There are several roughness geometries provides in different forms such as ribs, wire mesh, baffles etc. which is used to enhance the heat transfer from the surface of the solar air heater. Experimental investigation shows that artificial roughness can give essential enhancement in heat transfer rate which improves the thermal performance of solar air heater. It has been observed that with the use of jet impingement on the base plate three times higher heat transfer coefficient is achieved due to highly turbulent impingement boundary layers. It is required to understand how the flow is been affected with the use of different roughness geometries in the form of repeated ribs with jet impingements.
Thermodynamic analysis of N 2 O transcritical refrigeration cycle using dedicated mechanical subc... more Thermodynamic analysis of N 2 O transcritical refrigeration cycle using dedicated mechanical subcooling cycle has been carried out in the present work. The transcritical cycle with the mechanical subcooling is evaluated for three different evaporator temperatures 5,-5 and-30ºC with different degrees of subcooling and for the environment temperatures range from 20 to 40 ºC using propane as refrigerant for the subcooling cycle. Performance of N 2 O transcritical cycle has been compared with CO 2 transcritical cycle. The results show that N 2 O transcritical cycle is better than CO 2 transcritical cycle for environment temperature above 25°C, which is an important fact for countries having tropical climate. It has been found that using combined cycle, the maximum increments in COP and in specific cooling capacity are 22% and 30% respectively. It has also been found that using mechanical subcooling cycle, the reduction in optimum heat rejection pressure is higher for lower evaporator temperature i.e.-30 °C and power consumption ratio is higher for higher evaporator temperature i.e. 5 °C. Further, the increment in COP using different refrigerants in mechanical subcooling cycle has been presented, where no significant differences have been found. The increment indicates that this cycle is more efficient for the environment temperatures above 30 °C.
Over the past few decades each and every organization, be it an industry for production, a unit o... more Over the past few decades each and every organization, be it an industry for production, a unit of manufacturing, a government organization, a limited corporation, a banking sector or an educational institution is focusing on increasing profit margin. And in order to do that, one of the key factors is achieving maximum output with minimum resources (input). Therefore, it has become extremely important for organizations to plan the use of resources in the most optimum way.
—The suitability of walnut particle and coconut fibre as a biocomposite reinforcing material was ... more —The suitability of walnut particle and coconut fibre as a biocomposite reinforcing material was investigated. 20 wt% of walnut shell particle of size 1.618 m µ-2.685 m µ and 10 wt% of coconut fibre of length 2-3 mm were mixed in epoxy CY 230 resin for preparation of hybrid biocomposite. The tensile properties and flexural test of hybrid biocomposite reinforced with walnut shell particle and coconut fibre were evaluated and analysed. Scanning electro microscopy was employed to characterize the tensile properties and fracture behaviour of biocomposite. The results show that ultimate strength, modulus of elasticity and yield strength of biocomposite material are about 54.3%, 86.4% and 88.3% of pure epoxy resin respectively. The compressive ultimate strength of biocomposite is 44.45 MPa as compared to 55.16 MPa of epoxy resin. This results reveals that the addition of 20 wt% walnut particles and 10 wt% coconut fibres yield better ultimate strength with approximately 80.58% of pure epoxy. The flexural modulus of biocomposite is 1706.15 MPa which is about 86.3% of pure epoxy. The flexural strength of biocomposite is 34.04 MPa which is about 35.7% of pure epoxy.
The present investigation has been under taken keeping in mind some of the problems concerning th... more The present investigation has been under taken keeping in mind some of the problems concerning the crack propagation direction and growth under constant amplitude load in an inclined crack geometry. The present studies mainly focus on to develop and modified the crack growth criterion to account of the effect of biaxial factor, shearing loading and number of stress terms for different criterion. The effect of one, two and three solution on crack initiation angle determined on the basis of DET-criterion & MTS-criterion. It is seen that difference in crack initiation angle (α) obtained from two and three term solution of DET-criterion & MTS-criterion is significant and higher than one term solution. The comparisons of predicted result obtain from using DET-criterion and MTS-criterion has been made. When comparison is made between two terms solution, it is found that growth rate is higher in case of DET-criterion than MTS-criterion when α <45 0 , whereas fatigue growth rate obtain by MTS-criterion is found to be the higher than the DET-criterion for α >45 0. It is observed that only three terms are sufficient to determine the stress and displacement field ahead of the crack tip. Variation of crack initiation angle with crack angle for different biaxial load factor and shear load factor by DET-criterion and MTS-criterion for three term solution is compared. The crack initiation angle also depends upon biaxial factor and shear load factor. NOTATIONS: β = crack inclination angle 0 β = crack initiation angle 2a = Initial crack length r and θ = polar coordinate of crack tip II I K K , = mode I and mode II stress intensity factor xy y x τ σ σ , , = stress components b 1 = Biaxial factor b 2 = Shear or torsional load factor INTRODUCTION: Fracture mechanics has been established as an important principle dealing with the growth of fatigue crack. During recent years, the fracture mechanics has obtained a considerable importance for studding the crack growth behavior under static and fatigue loading. The majority of the research done in the area of fracture mechanics was accomplished in the opening mode only. Hence the practical application of the fracture mechanics is limited. The mixed mode crack growth problem has drawn comparably little attention, but is actually more realistic and possibly more dangerous than mode-I crack. The mixed mode growth occurs when a fatigue crack is nucleated along the inclusions or welded defects located making an angle with the axis of the applied load. The fatigue crack growth under multi axial stress is to be considering as mixed mode. The mixed mode cracks generally propagate in a non-self similar manner. Hence, in case of mixed mode loading condition, the study of the crack initiation angle and crack growth rate is of equal importance. A considerable amount of the work has been done to define governing mixed mode loading and crack growth behavior. Papadopoulos (1987) proposed the DET-criterion is based on determinants of the stress tensor. Using the stress as parameter, MTS-criterion proposed by Erdigan & Sih (1963) is based on the
Fracture mechanics has been established as an important principle dealing with the growth of fati... more Fracture mechanics has been established as an important principle dealing with the growth of fatigue crack. During recent years, the fracture mechanics has obtained a considerable importance for studding the crack growth behavior under static and fatigue loading. The largest number of in-service failures results from the scenario involving fluctuating, cyclic or repeated loading, usually combination with static load. Typically, a defect located near a stress raiser enlarges under repeated tensile stresses into a crack that continues to grow stably a small amount during each load cycle until the crack either penetrates the structure or attains critical length, after which unstable crack propagation occurs. The present investigation has been under taken keeping in mind some of the problems concerning the crack propagation direction and growth under constant amplitude load in an inclined crack geometry. The present studies mainly focus on to develop and modified the crack growth criterion to account of the effect of biaxial factor, shearing loading and number of stress terms for different criterion. The effect of one, two and three solution on crack initiation angle determined on the basis of DET-criterion & MTS criterion. 1.0 Introduction The majority of the research done in the area of fracture mechanics was accomplished in the opening mode only. Hence the practical application of the fracture mechanics is limited. The mixed mode crack growth problem has drawn comparably little attention, but is actually more realistic and possibly more dangerous than mode-I crack. The mixed mode growth occurs when a fatigue crack is nucleated along the inclusions or welded defects located making an angle with the axis of the applied load. The fatigue crack growth under multi axial stress is to be considering as mixed mode. The mixed mode cracks generally propagate in a non-self similar manner. Hence, in case of mixed mode loading condition, the study of the crack initiation angle and crack growth rate is of equal importance. The predictions of mixed mode crack growth direction, different criterion have been proposed. Using the stress as parameter, MTS-criterion proposed by Erdigan & Sih (1963) is based on the assumption that the material behaves ideally brittle. This assumption is not supported by all kind of material. SED-criterion of Sih (1974) is based on the minimum strain energy density principle. This criterion corresponds to maximum potential energy, which is regarded as the integral of field variable over some domain rather than a point and is insensitive to sign of the loading. T-criterion proposed by Theocaries et. al. (1982) is also based on the SED-criterion, which is modified by using a variable radius for core region. Papadopoulos (1987) proposed the DET-criterion is based on determinants of the stress tensor. The predicted crack initiation angles by DET-criterion are found to be much higher relative to the one obtained by the MTS or the SED criterion. The theoretical results obtained for different loading cases are shown and discussed by Khan et. al. (2000). They have shown that the result for MTS-criterion and T-criterion match exactly for all loading cases, although both have been derived on different theoretical basis. Prais (1963) co-relate the rate of crack growth to the stress intensity factor for simple opening (mode-I). Robert and Kibla (1971) indicated in their result that the fatigue crack under mixed loading grew in a manner which did not reduce the mode-II component of load to zero and that the growth rate was accelerating by mode-II components of the stress applied simultaneously. A considerable amount of the work has been done to define governing mixed mode loading and crack growth behavior.
The suitability of walnut particle and coconut fiber as a biocomposite reinforcing material was i... more The suitability of walnut particle and coconut fiber as a biocomposite reinforcing material was investigated. 20 wt% of walnut shell particles of size 1.618-2.685 and 10 wt% of coconut fibre of length 2-3 mm were mixed with epoxy CY 230 resin for preparation of hybrid biocomposite. The tensile properties and flexural test of hybrid biocomposite reinforced with walnut shell particle and coconut fiber were evaluated and analyzed. Scanning electron microscopy was employed to characterize the tensile properties and fracture behavior of biocomposite. The results show that ultimate strength, modulus of elasticity and yield strength of biocomposite material are about 54.3%, 86.4% and 88.3% of pure epoxy resin respectively. The flexural modulus of biocomposite is 1706.15 MPa which is about 86.3% of pure epoxy. The flexural strength of biocomposite is 34.04 MPa which is about 35.7% of pure epoxy.
In the current scenario where we are using 3G and 4G technologies for communication purposes the ... more In the current scenario where we are using 3G and 4G technologies for communication purposes the Mobile Ad Hoc Networks (MANETs) are generating a lot of interests. The next generation of mobile communications will include both prominent infrastructure wireless networks (3G, 4G) and novel mobile ad hoc networks. It is a collection of portable wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure. This allows portable mobile devices to establish a communication path without having any central infrastructure. Since there is no centralized infrastructure in the MANET and the mobile devices are moving randomly, they may give rise to various kinds of problems, such as energy efficient and multicast congestion control. This paper describes the primary problems of ad hoc networking by giving its related research background. Some of the technical challenges it poses are also presented, based on which the paper points out some of the key research issues for ad hoc networking technology that are expected to promote the development and accelerate the commercial applications of the MANET technology. Special attention is paid on network layer routing strategy and key research issues include new X-cast routing algorithms, security & reliability schemes, QoS model, and mechanisms for interworking with outside IP networks. INTRODUCTION: A mobile ad-hoc network (MANET) is composed of portable or mobile nodes without any infrastructure. Mobile nodes are self-organized to form a network over radio links. The goal of MANETs is to extend mobility into the realm of autonomous, mobile and wireless domains, where a set of nodes from the network by using some kind of the routing infrastructure in an ad-hoc fashion. The majority of applications of MANETs are in areas where fast and dynamic reconfiguration is necessary and wired network is not available. The mobile ad-hoc network is such a network which does not require any infrastructure like traditional wireless network. Initially, it can be useful for the smaller areas like with the computer lab, homes (For communicating with digital cameras, cooking ovens, washing machines, refrigerators, vacuum cleaners and thermostats), the classrooms, etc. But later on after it was successfully implemented and used in these small areas then there is tremendous scope of ad-hoc network. It can be used in military battlefields, emergency search, rescue sites, where participants share information dynamically using their mobile devices. These applications lend themselves well to multicast operations In the last decade, advancement in both hardware and software techniques have resulted in mobile hosts and wireless networking. We can categories mobile wireless communication in two distinct approaches: 1. With Infrastructure. The current or traditional wireless mobile network requires good infrastructure support on the cellular concept in which mobile devices communicate with other mobile devices with base stations connected to the fixed network infrastructure. Typical examples of this kind of wireless networks are GSM, UMTS, WLL, WLAN, etc.
The effect of bio-fibres and bio-particles on the fracture toughness has been investigated. Epoxy... more The effect of bio-fibres and bio-particles on the fracture toughness has been investigated. Epoxy resin is used as matrix material and different bio-fibers such as banana fiber, bagasse fiber, coconut fiber and particles such as silica and walnut shell particle with different wt% are added as reinforcing material. The mode I fracture toughness tests are conducted in a servo hydraulic universal testing machine. The results show that the fracture toughness of bio-composites reinforced with 20wt% bagasse or 10wt% coconut fiber are 1.108MPa and 1.094MPa , respectively which are about 8% and 7% higher than neat epoxy. Addition of 2 wt% of silica with 20 wt% of bagasse shows 60% increment of fracture toughness with respect to bagasse and 72% increment with respect to neat epoxy. Hybridisation of bagasse with banana fibers shows 54% decrease in fracture toughness as compared to bagasse and 13% increase as compared to banana. The overall fracture toughness of hybrid bio-composite of 10 wt% coconut fiber and 20 wt% of walnut shell particle is 1.367MPa which is about 25% higher than coconut fiber reinforced bio-composite.
Mixed-mode fracture characteristics of epoxy-based biocomposite reinforced with
20 wt% walnut she... more Mixed-mode fracture characteristics of epoxy-based biocomposite reinforced with 20 wt% walnut shell particle and 10 wt% coconut fibres are investigated. The biocomposite is fabricated using the squeeze casting method. The positive aspect of hybrid combination of fibre and particle reinforcement is advocated by comparing I, mode II and mixed-mode I/II fracture surfaces under a scanning electron microscope. An edgecracked semicircular arc specimen subjected to symmetric three-point bend (TPB) loading is suggested for fracture toughness testing of biocomposite material. A series of fracture tests are conducted on hybrid biocomposite using the proposed semicircular bend (SCAB) specimen geometry, TPB and four-point bend (FPB) specimens. The average mode I and II fracture toughness obtained from semicircular arc bend (SCAB) specimen are 1.319 MPa and 1.219 MPa ffiffiffiffi m p , respectively. The average values of modes I and II toughness obtained from TPB and FPB specimens are 1.267 and 0.754 MPa ffiffiffiffi m p . The overall ratio of mode I and mode II fracture toughness is found to be 0.762, which is very close to the predicted value of 0.87 by maximum tangential stress criterion. The results obtained from new SCAB geometry are validated with the results obtained from TPB and FPB specimen geometries by statistical significance test. Very good agreement is found between the experimental results obtained from TPB, FPB and the proposed SCAB specimens.
The rectangular specimens with an edge crack were
subjected to symmetric three-point bending and ... more The rectangular specimens with an edge crack were subjected to symmetric three-point bending and asymmetric four-point bending to determine the mode I and mode II fracture toughness of the walnut particle and coconut fiber-reinforced biocomposite. Epoxy resin was used as matrix material and 10 wt% of coconut fiber and 20 wt% of walnut shell particle were used as reinforcing materials. The mode I and mode II fracture toughness and mechanical tests were conducted on a servo hydraulic universal testing machine and the results were analyzed and discussed. POLYM. COMPOS., 36:167–173, 2015. VC 2014 Society of Plastics Engineers
Mixed-mode fracture characteristics of epoxy-based biocomposite reinforced with
20 wt% walnut she... more Mixed-mode fracture characteristics of epoxy-based biocomposite reinforced with 20 wt% walnut shell particle and 10 wt% coconut fibres are investigated. The biocomposite is fabricated using the squeeze casting method. The positive aspect of hybrid combination of fibre and particle reinforcement is advocated by comparing I, mode II and mixed-mode I/II fracture surfaces under a scanning electron microscope. An edgecracked semicircular arc specimen subjected to symmetric three-point bend (TPB) loading is suggested for fracture toughness testing of biocomposite material. A series of fracture tests are conducted on hybrid biocomposite using the proposed semicircular bend (SCAB) specimen geometry, TPB and four-point bend (FPB) specimens. The average mode I and II fracture toughness obtained from semicircular arc bend (SCAB) specimen are 1.319 MPa and 1.219 MPa ffiffiffiffi m p , respectively. The average values of modes I and II toughness obtained from TPB and FPB specimens are 1.267 and 0.754 MPa ffiffiffiffi m p . The overall ratio of mode I and mode II fracture toughness is found to be 0.762, which is very close to the predicted value of 0.87 by maximum tangential stress criterion. The results obtained from new SCAB geometry are validated with the results obtained from TPB and FPB specimen geometries by statistical significance test. Very good agreement is found between the experimental results obtained from TPB, FPB and the proposed SCAB specimens.
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Papers by Dinesh Rao
with 20wt% bagasse or 10wt% coconut fiber are 1.108MPa and 1.094MPa , respectively which are about 8% and 7% higher than neat epoxy. Addition of 2 wt% of silica with 20 wt% of bagasse shows 60% increment of fracture toughness with respect to bagasse and 72% increment with respect to neat epoxy. Hybridisation of bagasse with banana fibers shows 54% decrease in fracture toughness as compared to bagasse and 13% increase as compared to banana. The overall fracture toughness of hybrid bio-composite of 10 wt% coconut fiber and 20 wt% of walnut shell particle is 1.367MPa which is about 25% higher than coconut fiber reinforced bio-composite.
20 wt% walnut shell particle and 10 wt% coconut fibres are investigated. The biocomposite
is fabricated using the squeeze casting method. The positive aspect of hybrid combination
of fibre and particle reinforcement is advocated by comparing I, mode II and
mixed-mode I/II fracture surfaces under a scanning electron microscope. An edgecracked
semicircular arc specimen subjected to symmetric three-point bend (TPB) loading
is suggested for fracture toughness testing of biocomposite material. A series of
fracture tests are conducted on hybrid biocomposite using the proposed semicircular
bend (SCAB) specimen geometry, TPB and four-point bend (FPB) specimens. The average
mode I and II fracture toughness obtained from semicircular arc bend (SCAB) specimen
are 1.319 MPa and 1.219 MPa ffiffiffiffi m
p
, respectively. The average values of modes I and II
toughness obtained from TPB and FPB specimens are 1.267 and 0.754 MPa ffiffiffiffi m
p
. The
overall ratio of mode I and mode II fracture toughness is found to be 0.762, which is very
close to the predicted value of 0.87 by maximum tangential stress criterion. The results
obtained from new SCAB geometry are validated with the results obtained from TPB
and FPB specimen geometries by statistical significance test. Very good agreement is
found between the experimental results obtained from TPB, FPB and the proposed
SCAB specimens.
subjected to symmetric three-point bending and asymmetric
four-point bending to determine the mode I and
mode II fracture toughness of the walnut particle and
coconut fiber-reinforced biocomposite. Epoxy resin
was used as matrix material and 10 wt% of coconut
fiber and 20 wt% of walnut shell particle were used as
reinforcing materials. The mode I and mode II fracture
toughness and mechanical tests were conducted on a
servo hydraulic universal testing machine and the
results were analyzed and discussed. POLYM. COMPOS.,
36:167–173, 2015. VC 2014 Society of Plastics Engineers
20 wt% walnut shell particle and 10 wt% coconut fibres are investigated. The biocomposite
is fabricated using the squeeze casting method. The positive aspect of hybrid combination
of fibre and particle reinforcement is advocated by comparing I, mode II and
mixed-mode I/II fracture surfaces under a scanning electron microscope. An edgecracked
semicircular arc specimen subjected to symmetric three-point bend (TPB) loading
is suggested for fracture toughness testing of biocomposite material. A series of
fracture tests are conducted on hybrid biocomposite using the proposed semicircular
bend (SCAB) specimen geometry, TPB and four-point bend (FPB) specimens. The average
mode I and II fracture toughness obtained from semicircular arc bend (SCAB) specimen
are 1.319 MPa and 1.219 MPa ffiffiffiffi m
p
, respectively. The average values of modes I and II
toughness obtained from TPB and FPB specimens are 1.267 and 0.754 MPa ffiffiffiffi m
p
. The
overall ratio of mode I and mode II fracture toughness is found to be 0.762, which is very
close to the predicted value of 0.87 by maximum tangential stress criterion. The results
obtained from new SCAB geometry are validated with the results obtained from TPB
and FPB specimen geometries by statistical significance test. Very good agreement is
found between the experimental results obtained from TPB, FPB and the proposed
SCAB specimens.
with 20wt% bagasse or 10wt% coconut fiber are 1.108MPa and 1.094MPa , respectively which are about 8% and 7% higher than neat epoxy. Addition of 2 wt% of silica with 20 wt% of bagasse shows 60% increment of fracture toughness with respect to bagasse and 72% increment with respect to neat epoxy. Hybridisation of bagasse with banana fibers shows 54% decrease in fracture toughness as compared to bagasse and 13% increase as compared to banana. The overall fracture toughness of hybrid bio-composite of 10 wt% coconut fiber and 20 wt% of walnut shell particle is 1.367MPa which is about 25% higher than coconut fiber reinforced bio-composite.
20 wt% walnut shell particle and 10 wt% coconut fibres are investigated. The biocomposite
is fabricated using the squeeze casting method. The positive aspect of hybrid combination
of fibre and particle reinforcement is advocated by comparing I, mode II and
mixed-mode I/II fracture surfaces under a scanning electron microscope. An edgecracked
semicircular arc specimen subjected to symmetric three-point bend (TPB) loading
is suggested for fracture toughness testing of biocomposite material. A series of
fracture tests are conducted on hybrid biocomposite using the proposed semicircular
bend (SCAB) specimen geometry, TPB and four-point bend (FPB) specimens. The average
mode I and II fracture toughness obtained from semicircular arc bend (SCAB) specimen
are 1.319 MPa and 1.219 MPa ffiffiffiffi m
p
, respectively. The average values of modes I and II
toughness obtained from TPB and FPB specimens are 1.267 and 0.754 MPa ffiffiffiffi m
p
. The
overall ratio of mode I and mode II fracture toughness is found to be 0.762, which is very
close to the predicted value of 0.87 by maximum tangential stress criterion. The results
obtained from new SCAB geometry are validated with the results obtained from TPB
and FPB specimen geometries by statistical significance test. Very good agreement is
found between the experimental results obtained from TPB, FPB and the proposed
SCAB specimens.
subjected to symmetric three-point bending and asymmetric
four-point bending to determine the mode I and
mode II fracture toughness of the walnut particle and
coconut fiber-reinforced biocomposite. Epoxy resin
was used as matrix material and 10 wt% of coconut
fiber and 20 wt% of walnut shell particle were used as
reinforcing materials. The mode I and mode II fracture
toughness and mechanical tests were conducted on a
servo hydraulic universal testing machine and the
results were analyzed and discussed. POLYM. COMPOS.,
36:167–173, 2015. VC 2014 Society of Plastics Engineers
20 wt% walnut shell particle and 10 wt% coconut fibres are investigated. The biocomposite
is fabricated using the squeeze casting method. The positive aspect of hybrid combination
of fibre and particle reinforcement is advocated by comparing I, mode II and
mixed-mode I/II fracture surfaces under a scanning electron microscope. An edgecracked
semicircular arc specimen subjected to symmetric three-point bend (TPB) loading
is suggested for fracture toughness testing of biocomposite material. A series of
fracture tests are conducted on hybrid biocomposite using the proposed semicircular
bend (SCAB) specimen geometry, TPB and four-point bend (FPB) specimens. The average
mode I and II fracture toughness obtained from semicircular arc bend (SCAB) specimen
are 1.319 MPa and 1.219 MPa ffiffiffiffi m
p
, respectively. The average values of modes I and II
toughness obtained from TPB and FPB specimens are 1.267 and 0.754 MPa ffiffiffiffi m
p
. The
overall ratio of mode I and mode II fracture toughness is found to be 0.762, which is very
close to the predicted value of 0.87 by maximum tangential stress criterion. The results
obtained from new SCAB geometry are validated with the results obtained from TPB
and FPB specimen geometries by statistical significance test. Very good agreement is
found between the experimental results obtained from TPB, FPB and the proposed
SCAB specimens.