ABSTRACT: The objective of this study is to develop a new biocomposite material with high deforma... more ABSTRACT: The objective of this study is to develop a new biocomposite material with high deformation ability. In this regard, the thermal, rheological, and thermophysical properties of this new composite were characterized as a function of temperature and filler concentration. High density polyethylene (HDPE) was the matrix of this new composite which was reinforced with six sawdust con-centrations 0%, 20%, 30%, 40%, 50%, and 60%. Maleic anhydride grafted polyethylene (PE-g-MA) was used as coupling agent. Addi-tion of sawdust with PE-g-MA increased significantly the complex viscosity, the storage modulus (G0), and loss modulus (G00) of the matrix. The superposition of the complex viscosity curves using temperature dependent shift factor, allowed the construction of a vis-cosity master curve covering a wide range of temperatures. Arrhenius law was used for the relationship of the shift factor to tempera-ture. Furthermore, method of Van Gurp and Palmen (tan delta vs. G*) is also used...
The full potential of plastic gear usage is limited by not only poor mechanical properties but al... more The full potential of plastic gear usage is limited by not only poor mechanical properties but also equally poor temperature limits and poor heat conduction properties. Cooling holes were developed to decrease the amount of thermal damage on the contact surface. These cooling holes promote increased stress and tooth deflection, thus exerting a negative effect. This article compares various cooling holes for plastic gear configurations and proposes novel cooling holes. Thermal and mechanical simulations that consider specific aspects of plastic gear meshing were performed. The main objective of this article was to verify the best methods for reducing thermal damage through cooling holes. The results indicate the best compromise between the temperature reduction and the mechanical properties of the new tooth geometry. The results also indicate that the simple variations in the cooling holes proposed can improve tooth performance.
In this work, laminated polyester thermoset composites based on palm tree fibers extracted from p... more In this work, laminated polyester thermoset composites based on palm tree fibers extracted from palms leaflets and glass mats fibers were manufactured to develop hybrid compositions with good mechanical properties; the mixture of fibers was elaborated to not exceed 25 vol.%. Samples were prepared with a resin transfer molding (RTM) method and mechanically characterized using tensile and flexural, hardness, and impact tests, and ultrasonic waves as a non-destructive technique. The water sorption of these composite materials was carried out in addition to solar irradiation aging for approximately 300 days to predict the applicability and the long-term performance of the manufactured composites. Results have shown that the use of glass fibers significantly increased all properties; however, an optimum combination of the mixture could be interesting and could be developed with less glass sheet and more natural fibers, which is the goal of this study. On the other hand, exposure to natur...
ABSTRACT: The objective of this study is to develop a new biocomposite material with high deforma... more ABSTRACT: The objective of this study is to develop a new biocomposite material with high deformation ability. In this regard, the thermal, rheological, and thermophysical properties of this new composite were characterized as a function of temperature and filler concentration. High density polyethylene (HDPE) was the matrix of this new composite which was reinforced with six sawdust con-centrations 0%, 20%, 30%, 40%, 50%, and 60%. Maleic anhydride grafted polyethylene (PE-g-MA) was used as coupling agent. Addi-tion of sawdust with PE-g-MA increased significantly the complex viscosity, the storage modulus (G0), and loss modulus (G00) of the matrix. The superposition of the complex viscosity curves using temperature dependent shift factor, allowed the construction of a vis-cosity master curve covering a wide range of temperatures. Arrhenius law was used for the relationship of the shift factor to tempera-ture. Furthermore, method of Van Gurp and Palmen (tan delta vs. G*) is also used...
Avant de citer ce rapport technique, veuillez visiter notre site Web (https://www.gerad.ca/fr/pap... more Avant de citer ce rapport technique, veuillez visiter notre site Web (https://www.gerad.ca/fr/papers/G-2018-73) afin de mettre à jour vos données de référence, s’il a été publié dans une revue scientifique. The series Les Cahiers du GERAD consists of working papers carried out by our members. Most of these pre-prints have been submitted to peer-reviewed journals. When accepted and published, if necessary, the original pdf is removed and a link to the published article is added.
The combined effect of the liquid flow slip and wall heat flux on the flow in a microchannel betw... more The combined effect of the liquid flow slip and wall heat flux on the flow in a microchannel between two parallel plates was investigated. The pressure-driven flow and the electroosmosis were taken into account. To find the electric potential, the flow and the thermal parameters, the Poisson-Boltzmann, the modified Navier-Stokes and the energy equations were solved for a hydraulic and thermal steady fully-developed laminar flow of an incompressible fluid. The results achieved revealed the influence of the slip velocity, the pressure difference and the heat flux on the flow and heat transfer characteristics. To validate the developed approach, a comparison of results was made.
Cmes-computer Modeling in Engineering & Sciences, 2011
During the design process of membrane structure to resist to high pressure loading, and the chara... more During the design process of membrane structure to resist to high pressure loading, and the characterization of hyperelastic material, a structure made up of thin rubber undergoes large deformation and rotation under high pressure loading out of high pressurized gas. Until recently, to simulate the inflation of the hyperelastic membrane, a uniform pressure based on thermodynamic model or experimental tests is applied to the structure, as boundary conditions. From a computational time point of view, this approach is very fast, since no computational fluid dynamics is involved in the simulation. However, at the late stage of the membrane inflation, uniform pressure simulations lead to numerical instability due to the lack of fluid that generates damping effects and prevent numerical instability. Thus the uniform pressure assumption is unstable at the end phase of the inflation for long time duration. To simulate accurately the inflation process, computational fluid dynamics in a movin...
Multiphysics Simulations in Automotive and Aerospace Applications, 2021
Abstract Simulation of airbag and membrane deployment under pressurized gas problems becomes more... more Abstract Simulation of airbag and membrane deployment under pressurized gas problems becomes more and more the focus of computational engineering, where finite element methods (FEMs) for structural mechanics and finite volume for computational fluid dynamics are dominant. New formulations have been developed for fluid structure interaction (FSI) applications using mesh free methods as smooth particle hydrodynamic (SPH) method. Up to these days very little has been done to compare different methods and assess which one would be more suitable. For small deformation, FEM Lagrangian formulation can solve structure interface and material boundary accurately, the main limitation of the formulation is high mesh distortion for large deformation and moving structure. One of the commonly used approaches to solve these problems is the arbitrary Lagrangian Eulerian (ALE) formulation which has been used with success in the simulation of FSI with large structure motion such as sloshing fuel tank in automotive industry and bird impact in aeronautic industry. For some applications, including bird impact and high velocity impact problems, engineers have switched from ALE to SPH method to reduce central processing unit (CPU) time and save memory allocation. Both ALE and SPH methods are described and compared here using similar mesh size, each ALE element is replaced by an SPH particle at the element center. From different simulation, it has been observed that for the SPH method to provide similar results as ALE or Lagrangian formulations, the SPH meshing needs to be finer than the ALE mesh. A contact algorithm is performed at the FSI for both SPH and ALE formulations. A simulation of airbag membrane deployment generated by high pressurized gas is performed.
Abstract In the last decades, research on atmospheric icing of structures such as power transmiss... more Abstract In the last decades, research on atmospheric icing of structures such as power transmission lines has attracted much interest. Accumulation and the shedding of atmospheric ice from overhead transmission lines and ground wires may cause their rupture and tower collapses, leading to power outages. The present work concerns a study of the compressive strength of atmospheric ice, under different experimental conditions such as strain rate, temperature, and porosity. For this reason, ice was accumulated in the closed loop wind tunnel at CIGELE (Industrial Chair on Atmospheric Icing of Power Network Equipment), under three temperatures (− 20, − 15 and − 5 °C). The wind speed inside the tunnel was set at 20 m/s in order to obtain a mean volume droplet diameter (MVD) of 40 μm and a liquid water content (LWC) of 2.5 g/m 3 . Each type of ice was tested at the same temperature at which it had been accumulated. A tomographic analysis was carried out on a small specimen (cylinder of 1 cm diameter × 2 cm length) for each temperature in order to quantify the porosity and determine the grain size and their distribution. The obtained results show a strong dependence of the compressive strength on temperature, strain rate and porosity. The ductile–brittle transition was identified within a strain rate ranging between 10 − 4 s − 1 and 10 − 3 s − 1 . It was found that compressive strength increases with decreasing temperature for deaerated ice. However, for atmospheric porous ice, compressive strength increases until − 15 °C, then decreases for lower temperatures. Compressive strength of atmospheric ice is highly dependent on porosity, which is related to the amount, size and distribution of pores inside the ice.
ABSTRACT: The objective of this study is to develop a new biocomposite material with high deforma... more ABSTRACT: The objective of this study is to develop a new biocomposite material with high deformation ability. In this regard, the thermal, rheological, and thermophysical properties of this new composite were characterized as a function of temperature and filler concentration. High density polyethylene (HDPE) was the matrix of this new composite which was reinforced with six sawdust con-centrations 0%, 20%, 30%, 40%, 50%, and 60%. Maleic anhydride grafted polyethylene (PE-g-MA) was used as coupling agent. Addi-tion of sawdust with PE-g-MA increased significantly the complex viscosity, the storage modulus (G0), and loss modulus (G00) of the matrix. The superposition of the complex viscosity curves using temperature dependent shift factor, allowed the construction of a vis-cosity master curve covering a wide range of temperatures. Arrhenius law was used for the relationship of the shift factor to tempera-ture. Furthermore, method of Van Gurp and Palmen (tan delta vs. G*) is also used...
The full potential of plastic gear usage is limited by not only poor mechanical properties but al... more The full potential of plastic gear usage is limited by not only poor mechanical properties but also equally poor temperature limits and poor heat conduction properties. Cooling holes were developed to decrease the amount of thermal damage on the contact surface. These cooling holes promote increased stress and tooth deflection, thus exerting a negative effect. This article compares various cooling holes for plastic gear configurations and proposes novel cooling holes. Thermal and mechanical simulations that consider specific aspects of plastic gear meshing were performed. The main objective of this article was to verify the best methods for reducing thermal damage through cooling holes. The results indicate the best compromise between the temperature reduction and the mechanical properties of the new tooth geometry. The results also indicate that the simple variations in the cooling holes proposed can improve tooth performance.
In this work, laminated polyester thermoset composites based on palm tree fibers extracted from p... more In this work, laminated polyester thermoset composites based on palm tree fibers extracted from palms leaflets and glass mats fibers were manufactured to develop hybrid compositions with good mechanical properties; the mixture of fibers was elaborated to not exceed 25 vol.%. Samples were prepared with a resin transfer molding (RTM) method and mechanically characterized using tensile and flexural, hardness, and impact tests, and ultrasonic waves as a non-destructive technique. The water sorption of these composite materials was carried out in addition to solar irradiation aging for approximately 300 days to predict the applicability and the long-term performance of the manufactured composites. Results have shown that the use of glass fibers significantly increased all properties; however, an optimum combination of the mixture could be interesting and could be developed with less glass sheet and more natural fibers, which is the goal of this study. On the other hand, exposure to natur...
ABSTRACT: The objective of this study is to develop a new biocomposite material with high deforma... more ABSTRACT: The objective of this study is to develop a new biocomposite material with high deformation ability. In this regard, the thermal, rheological, and thermophysical properties of this new composite were characterized as a function of temperature and filler concentration. High density polyethylene (HDPE) was the matrix of this new composite which was reinforced with six sawdust con-centrations 0%, 20%, 30%, 40%, 50%, and 60%. Maleic anhydride grafted polyethylene (PE-g-MA) was used as coupling agent. Addi-tion of sawdust with PE-g-MA increased significantly the complex viscosity, the storage modulus (G0), and loss modulus (G00) of the matrix. The superposition of the complex viscosity curves using temperature dependent shift factor, allowed the construction of a vis-cosity master curve covering a wide range of temperatures. Arrhenius law was used for the relationship of the shift factor to tempera-ture. Furthermore, method of Van Gurp and Palmen (tan delta vs. G*) is also used...
Avant de citer ce rapport technique, veuillez visiter notre site Web (https://www.gerad.ca/fr/pap... more Avant de citer ce rapport technique, veuillez visiter notre site Web (https://www.gerad.ca/fr/papers/G-2018-73) afin de mettre à jour vos données de référence, s’il a été publié dans une revue scientifique. The series Les Cahiers du GERAD consists of working papers carried out by our members. Most of these pre-prints have been submitted to peer-reviewed journals. When accepted and published, if necessary, the original pdf is removed and a link to the published article is added.
The combined effect of the liquid flow slip and wall heat flux on the flow in a microchannel betw... more The combined effect of the liquid flow slip and wall heat flux on the flow in a microchannel between two parallel plates was investigated. The pressure-driven flow and the electroosmosis were taken into account. To find the electric potential, the flow and the thermal parameters, the Poisson-Boltzmann, the modified Navier-Stokes and the energy equations were solved for a hydraulic and thermal steady fully-developed laminar flow of an incompressible fluid. The results achieved revealed the influence of the slip velocity, the pressure difference and the heat flux on the flow and heat transfer characteristics. To validate the developed approach, a comparison of results was made.
Cmes-computer Modeling in Engineering & Sciences, 2011
During the design process of membrane structure to resist to high pressure loading, and the chara... more During the design process of membrane structure to resist to high pressure loading, and the characterization of hyperelastic material, a structure made up of thin rubber undergoes large deformation and rotation under high pressure loading out of high pressurized gas. Until recently, to simulate the inflation of the hyperelastic membrane, a uniform pressure based on thermodynamic model or experimental tests is applied to the structure, as boundary conditions. From a computational time point of view, this approach is very fast, since no computational fluid dynamics is involved in the simulation. However, at the late stage of the membrane inflation, uniform pressure simulations lead to numerical instability due to the lack of fluid that generates damping effects and prevent numerical instability. Thus the uniform pressure assumption is unstable at the end phase of the inflation for long time duration. To simulate accurately the inflation process, computational fluid dynamics in a movin...
Multiphysics Simulations in Automotive and Aerospace Applications, 2021
Abstract Simulation of airbag and membrane deployment under pressurized gas problems becomes more... more Abstract Simulation of airbag and membrane deployment under pressurized gas problems becomes more and more the focus of computational engineering, where finite element methods (FEMs) for structural mechanics and finite volume for computational fluid dynamics are dominant. New formulations have been developed for fluid structure interaction (FSI) applications using mesh free methods as smooth particle hydrodynamic (SPH) method. Up to these days very little has been done to compare different methods and assess which one would be more suitable. For small deformation, FEM Lagrangian formulation can solve structure interface and material boundary accurately, the main limitation of the formulation is high mesh distortion for large deformation and moving structure. One of the commonly used approaches to solve these problems is the arbitrary Lagrangian Eulerian (ALE) formulation which has been used with success in the simulation of FSI with large structure motion such as sloshing fuel tank in automotive industry and bird impact in aeronautic industry. For some applications, including bird impact and high velocity impact problems, engineers have switched from ALE to SPH method to reduce central processing unit (CPU) time and save memory allocation. Both ALE and SPH methods are described and compared here using similar mesh size, each ALE element is replaced by an SPH particle at the element center. From different simulation, it has been observed that for the SPH method to provide similar results as ALE or Lagrangian formulations, the SPH meshing needs to be finer than the ALE mesh. A contact algorithm is performed at the FSI for both SPH and ALE formulations. A simulation of airbag membrane deployment generated by high pressurized gas is performed.
Abstract In the last decades, research on atmospheric icing of structures such as power transmiss... more Abstract In the last decades, research on atmospheric icing of structures such as power transmission lines has attracted much interest. Accumulation and the shedding of atmospheric ice from overhead transmission lines and ground wires may cause their rupture and tower collapses, leading to power outages. The present work concerns a study of the compressive strength of atmospheric ice, under different experimental conditions such as strain rate, temperature, and porosity. For this reason, ice was accumulated in the closed loop wind tunnel at CIGELE (Industrial Chair on Atmospheric Icing of Power Network Equipment), under three temperatures (− 20, − 15 and − 5 °C). The wind speed inside the tunnel was set at 20 m/s in order to obtain a mean volume droplet diameter (MVD) of 40 μm and a liquid water content (LWC) of 2.5 g/m 3 . Each type of ice was tested at the same temperature at which it had been accumulated. A tomographic analysis was carried out on a small specimen (cylinder of 1 cm diameter × 2 cm length) for each temperature in order to quantify the porosity and determine the grain size and their distribution. The obtained results show a strong dependence of the compressive strength on temperature, strain rate and porosity. The ductile–brittle transition was identified within a strain rate ranging between 10 − 4 s − 1 and 10 − 3 s − 1 . It was found that compressive strength increases with decreasing temperature for deaerated ice. However, for atmospheric porous ice, compressive strength increases until − 15 °C, then decreases for lower temperatures. Compressive strength of atmospheric ice is highly dependent on porosity, which is related to the amount, size and distribution of pores inside the ice.
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