Monotonic deformation behavior of ferrite-martensite dual phase steels with martensite volume of 1343% have been analyzed in the current investigation using micromechanics based finite element simulation on representative volume... more
Monotonic deformation behavior of ferrite-martensite dual phase steels with martensite volume of 1343% have been analyzed in the current investigation using micromechanics based finite element simulation on representative volume elements. The effects of martensite volume fraction on the strain partitioning behavior between soft ferrite matrix and hard martensite islands in dual phase steels during tensile deformation have been investigated. As a consequence of strain incompatibility between hard martensite and soft ferrite phases, inho-mogeneous deformation and finally deformation localization occur during tensile deformation. Restricted local deformation in ferrite phase caused by the adjacent martensite islands triggers the local stress triaxiality development. As the martensite volume fraction increases, the local deformation restrictions in ferrite phase also increases and which results in higher stress triaxiality development. Similarly the strain partitioning behavior between ferrite matrix and martensite island is also influenced by the volume fraction of martensite. The strain partitioning coefficient increases with increasing martensite volume fraction.
Protecting a car in a low-speed collision is an essential for passenger safety. A box-shaped bumper beams were common and served as shock absorbers in a potential crash. In this simulation study, their comparative deformation and failure... more
Protecting a car in a low-speed collision is an essential for passenger safety. A box-shaped bumper beams were common and served as shock absorbers in a potential crash. In this simulation study, their comparative deformation and failure analysis of hollow and solid bumper beam is investigated. In this study, Aluminium 6061 T4 is used for the analysis. The crash phenomenon is simulated in which the vehicle hits a deformable concrete wall at a specified speed. Modeling of solid and hollow car bumper is approximated from Honda Civic car’s width and design. The bumper beam, actuating tubes and the retention plates supporting the beam and the concrete wall are modeled as deformable bodies. The crash event is simulated using the elastic–plastic finite element model through Von Mises yield criteria and isotropic hardening rule. The deformation behaviour and ductile failure of the solid and hollow bumper is predicted in the form of plastic strain localization in this study and compared.
The solar buoy is primarily aimed towards utilizing the abundant water bodies available in our country. The present work is a design problem for the design and development of a 3.6 KWHr peak power output solar buoy system. The design is... more
The solar buoy is primarily aimed towards utilizing the abundant water bodies available in our country. The present work is a design problem for the design and development of a 3.6 KWHr peak power output solar buoy system. The design is made for practical implementation of the structure in several remote locations of West Bengal, India. The present design of Solar buoy structure mainly consists of L-section & tubular beams. The forced vibration analysis using Nastran and Patran software is done towards high simulating structural loads because of high speed gust of winds (max. 90 km/hr.). Light weight structure will control the solar buoy system in terms of minimizing the vibration amplitude and frequency so as to improve the efficiency of the system. Simulation results show that the combined structure achieves a synergy between the wind, the weight of the system and buoyancy of the water body. Maximum stress is very much negligible which focuses on the stability of the structure. von-Mises stress obtained is obtained much below the yield point stress of the material. However, the construction design is owing to the cross wind disturbances in the vicinity of solar buoy installation.
The cyclic plastic deformation of an archetypal microstructure dual phase steels has been examined via micromechanics modelling based on representative volume elements technique. The dual phase steel has soft ferrite – matrix with hard... more
The cyclic plastic deformation of an archetypal microstructure dual phase steels has been examined via micromechanics modelling based on representative volume elements technique. The dual phase steel has soft ferrite – matrix with hard martensite – islands, which are distributed in a discrete manner. In the field of automobile industries, the suitable combination of strain hardening, strength and ductility, and their lean combination represent them as an economically desire option for huge multiple lightweight options. In this numerical approach, different microstructures for micromechanical modelling were constructed to detailed examination and analysis for the tensile and cyclic deformation response of dual phase steels. Due to the distinct difference in the stress–strain responses of ferrite and martensite phases, incompatibility of strain between matrix-softer ferrite and island-harder martensite phase arises during tensile straining. The effect of strain partitioning in cyclic plastic deformation response of dual phase steel has been studied in the present investigation. Apart from this, effect of martensite volume fraction on cyclic stress–strain response of dual phase steels, cyclic plastic deformation distribution in individual phases and cyclic deformation inhomogeneity at microstructural level have been systematically investigated.
An inclusion generates a stress concentration and it plays a crucial role both damage evolution and mechanical response of materials. In the current work, the stress fields around hard and soft circular inclusions are analytically... more
An inclusion generates a stress concentration and it plays a crucial role both damage evolution and mechanical response of materials. In the current work, the stress fields around hard and soft circular inclusions are analytically determined within the framework of the linear theory of elasticity. The Kirsch's solution is here modified for the case of a hard or a soft inclusion, by applying both the theory of superposition and equi-energy stress partition criterion. The presented approach is validated by finite element simulations by considering with six different hard and soft inclusions.
This paper deals with the location optimization of a cutout within a laminated cantilever beam for maximizing the lateral buckling load. Various shapes of cutout, such as circular, elliptical, triangular, are generally used in structural... more
This paper deals with the location optimization of a cutout within a laminated cantilever beam for maximizing the lateral buckling load. Various shapes of cutout, such as circular, elliptical, triangular, are generally used in structural components as a design requirement or sometime to reduce the overall weight of the structures. In this study, a laminated cantilever beam, with a single cutout, is considered. The beam is subjected to a concentrated load at the free end. The objective is to obtain the optimal location of the cutout which resist maximum lateral buckling load. For this an optimization routine has been used in which a finite element calculation of critical lateral buckling load in ANSYS is coupled with an in-built global optimization tool (Genetic Algorithm) in MATLAB. The optimal results are reported for various cases arising from change of geometry and material properties of the plate. It has been concluded that the position of cutout in the laminated beam plays a si...
In this paper, a study of double diffusive convection in an anisotropic porous layer, saturated with viscoelastic fluid, heated form below, and cooled from above, has been performed; the fluid and solid phases are not in thermal... more
In this paper, a study of double diffusive convection in an anisotropic porous layer, saturated with viscoelastic fluid, heated form below, and cooled from above, has been performed; the fluid and solid phases are not in thermal equilibrium. Extended Darcy model, which includes the time derivative term in the momentum equation, has been used. For the fluid and solid phase temperature fields, a two-field model has been used separately for energy equation. Linear stability analysis is performed, using normal mode technique, and the expression for Rayleigh number has been obtained. It is found that small inter-phase heat coefficient has substantial effect on the stability of the system. The criterion for both stationary and oscillatory convection is derived analytically. The effects of various parameters on the stability of the system have been investigated. A weak nonlinear stability analysis based on the truncated representation of Fourier series is performed to find Nusselt number and Sherwood number. Further, we studied the transient behavior of the Nusselt number and Sherwood number by solving the finite amplitude equations using a numerical method. The results obtained during the analysis have been presented graphically. A study of streamlines, isotherms, and isohalines has been also made for fluid and solid phases.
Double diffusive convection in a rotating anisotropic porous layer, saturated by a viscoelastic fluid, heated from below and cooled from above has been studied making linear and non-linear stability analyses. The fluid and solid phases... more
Double diffusive convection in a rotating anisotropic porous layer, saturated by a viscoelastic fluid, heated from below and cooled from above has been studied making linear and non-linear stability analyses. The fluid and solid phases are considered to be in equilibrium. In momentum equation, we have employed the Darcy equation which includes both time derivative and Coriolis terms. The linear theory based on normal mode method is considered to find the criteria for the onset of stationary and oscillatory convection. A weak non-linear analysis based on minimal representation of truncated Fourier series analysis containing only two terms has been used to find the Nusselt number and Sherwood number as functions of time. We have solved the finite amplitude equations using a numerical scheme. The results obtained, during the above analyses, have been presented graphically and the effects of various parameters on heat and mass transfer have been discussed. Finally, we have drawn the steady and unsteady streamlines, isotherms, and isohalines for various parameters.
• The study investigates the effect of alcohol addition to diesel on CI engine performances. • Thermal efficiency increases marginally with addition of ethanol and methanol to diesel. • Ignition delay for blended fuels is increased,... more
• The study investigates the effect of alcohol addition to diesel on CI engine performances. • Thermal efficiency increases marginally with addition of ethanol and methanol to diesel. • Ignition delay for blended fuels is increased, resulting to higher heat release. • Peak pressure rise is lower for alcohol blended fuels. • NOx, specific PM and smoke emissions decrease significantly. A B S T R A C T An attempt has been made to simulate a compression ignition engine using diesel-ethanol and diesel-methanol blends as fuels. The engine considered for the simulation is a single cylinder, naturally aspirated, water cooled, direct injection, four stroke diesel engine. During the simulation, the speed and the static injection timing are kept constant at 1500 rpm and 23°bTDC respectively. The commercial software named Diesel-RK used for this work is capable of predicting performance and combustion characteristics of the engine as well as the formation and emission of different harmful pollutants from it. The analysis of the predicted results shows that the efficiencies increase slightly and BSFC increases with methanol as well as ethanol addition to diesel. Most of the harmful pollutants in the exhaust are reduced significantly except CO2 with the use of alcohol blended fuels. Reduction in NOx emission is more with diesel-ethanol blend compared to diesel-methanol blend. The reverse trend was observed in the case of particulate matter and smoke emission.
