In this paper, the mechanical responses of a thick-walled functionally graded hollow cylinder subject to a uniform magnetic field and inner-pressurized loads are studied. Rather than directly assume the material const...In this paper, the mechanical responses of a thick-walled functionally graded hollow cylinder subject to a uniform magnetic field and inner-pressurized loads are studied. Rather than directly assume the material constants as some specific function forms displayed in pre-studies, we firstly give the volume fractions of different constituents of the functionally graded material(FGM) cylinder and then determine the expressions of the material constants. With the use of the Voigt method, the corresponding analytical solutions of displacements in the radial direction, the strain and stress components, and the perturbation magnetic field vector are derived. In the numerical part, the effects of the volume fraction on the displacement, strain and stress components, and the magnetic perturbation field vector are investigated. Moreover, by some appropriate choices of the material constants, we find that the obtained results in this paper can reduce to some special cases given in the previous studies.展开更多
Different failure modes and morphologies were found in the chemical vapor infiltration(CVI) 2D C/SiC torque tubes with different thickness. To characterize the density and porosity of the ceramic matrix composite(CMC)...Different failure modes and morphologies were found in the chemical vapor infiltration(CVI) 2D C/SiC torque tubes with different thickness. To characterize the density and porosity of the ceramic matrix composite(CMC) torque tube, a CT test was conducted. The archimedes drainage method was used to measure the density and porosity, and by adopting FEM software, the stress distribution and failure strength of the ceramic matrix composite torque tubes were calculated. A universal material test machine was used to implement torsional tests. Different torsional behaviors of CMC torque tubes with two different thicknesses were showed in the stress-strain curves. To analyze the predominant failure factors, SEM was used to observe the failure morphologies and cracks. 5 mm thickness CMC torque tube has reasonable fracture morphologies and a higher maximum shear strength and modulus.展开更多
Experiment on seamless tubes of aluminum alloy A6063 with initial thickness deviation of 0-20% was conducted through a free hydraulic bulging with tube ends free. The influence of initial thickness deviation on the cr...Experiment on seamless tubes of aluminum alloy A6063 with initial thickness deviation of 0-20% was conducted through a free hydraulic bulging with tube ends free. The influence of initial thickness deviation on the cross-section profile, thickness distribution, maximum internal pressure and maximum radial expansion was investigated. FEM simulation was also performed in order to examine and help explaining the experimental results. The results indicate that the internal pressure and maximum internal pressure appear to be little influenced by the initial thickness deviation, and that the cross-section profile of the bulged tube changes diversely and can not be a perfect circle. The results also suggest that the increase in initial thickness deviation may lead to a remarkable decrease in maximum radial expansion, and a rapid increase in thickness deviation and the center eccentricity of the inner and outer profiles.展开更多
Tube spinning technology is one of the effective methods of manufacturing large diameter thin-walled shapes. In this research, effects of major parameters of thermo mechanical tube spinning process such as preform'...Tube spinning technology is one of the effective methods of manufacturing large diameter thin-walled shapes. In this research, effects of major parameters of thermo mechanical tube spinning process such as preform's thickness, percentage of thickness reduction, mandrel rotational speed, feed rate, solution treatment time and aging treatment time on the wall thickness changes and process time in thermo-mechanical tube spinning process for fabrication of 2024 aluminum spun tubes using design of experiments (DOE), are studied. The statistical results are verified through some experiments. Results of experimental evaluation are analyzed by variance analysis and mathematic models are obtained. Finally using these models, input parameters for optimum production are achieved.展开更多
By elastic mechanics, the deformation of single throttle-slice for shock absorber was analyzed, the formula of its deformation was established. According to the relation of the deformation of multi-throttle-slices wit...By elastic mechanics, the deformation of single throttle-slice for shock absorber was analyzed, the formula of its deformation was established. According to the relation of the deformation of multi-throttle-slices with the pressure on each slice, the analytic formula of equivalent thickness of multi-throttle-slices was established. Followed is a practical example for the computation of the equivalent thickness of multi-throttle-slices, compared the computed results with that simulated by ANSYS. The results show that the computation method of equivalent thickness of multi-throttle-slices is accurate enough.展开更多
基金supported by the National Natural Science Foundation of China(No.11772041)
文摘In this paper, the mechanical responses of a thick-walled functionally graded hollow cylinder subject to a uniform magnetic field and inner-pressurized loads are studied. Rather than directly assume the material constants as some specific function forms displayed in pre-studies, we firstly give the volume fractions of different constituents of the functionally graded material(FGM) cylinder and then determine the expressions of the material constants. With the use of the Voigt method, the corresponding analytical solutions of displacements in the radial direction, the strain and stress components, and the perturbation magnetic field vector are derived. In the numerical part, the effects of the volume fraction on the displacement, strain and stress components, and the magnetic perturbation field vector are investigated. Moreover, by some appropriate choices of the material constants, we find that the obtained results in this paper can reduce to some special cases given in the previous studies.
基金Funded by the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(No.135-QP-2015)the Creative Research Foundation of Science and Technology on Thermostructural Composite Materials Laboratory(No.6142911010304)+1 种基金Natural Science Basic Research Plan in Shanxi Province of China(No.2017JM5110)China Postdoctoral Science Foundation(No.2015M570853)
文摘Different failure modes and morphologies were found in the chemical vapor infiltration(CVI) 2D C/SiC torque tubes with different thickness. To characterize the density and porosity of the ceramic matrix composite(CMC) torque tube, a CT test was conducted. The archimedes drainage method was used to measure the density and porosity, and by adopting FEM software, the stress distribution and failure strength of the ceramic matrix composite torque tubes were calculated. A universal material test machine was used to implement torsional tests. Different torsional behaviors of CMC torque tubes with two different thicknesses were showed in the stress-strain curves. To analyze the predominant failure factors, SEM was used to observe the failure morphologies and cracks. 5 mm thickness CMC torque tube has reasonable fracture morphologies and a higher maximum shear strength and modulus.
基金Project(0135023) supported by the Science Foundation of Guangxi Province, China
文摘Experiment on seamless tubes of aluminum alloy A6063 with initial thickness deviation of 0-20% was conducted through a free hydraulic bulging with tube ends free. The influence of initial thickness deviation on the cross-section profile, thickness distribution, maximum internal pressure and maximum radial expansion was investigated. FEM simulation was also performed in order to examine and help explaining the experimental results. The results indicate that the internal pressure and maximum internal pressure appear to be little influenced by the initial thickness deviation, and that the cross-section profile of the bulged tube changes diversely and can not be a perfect circle. The results also suggest that the increase in initial thickness deviation may lead to a remarkable decrease in maximum radial expansion, and a rapid increase in thickness deviation and the center eccentricity of the inner and outer profiles.
文摘Tube spinning technology is one of the effective methods of manufacturing large diameter thin-walled shapes. In this research, effects of major parameters of thermo mechanical tube spinning process such as preform's thickness, percentage of thickness reduction, mandrel rotational speed, feed rate, solution treatment time and aging treatment time on the wall thickness changes and process time in thermo-mechanical tube spinning process for fabrication of 2024 aluminum spun tubes using design of experiments (DOE), are studied. The statistical results are verified through some experiments. Results of experimental evaluation are analyzed by variance analysis and mathematic models are obtained. Finally using these models, input parameters for optimum production are achieved.
文摘By elastic mechanics, the deformation of single throttle-slice for shock absorber was analyzed, the formula of its deformation was established. According to the relation of the deformation of multi-throttle-slices with the pressure on each slice, the analytic formula of equivalent thickness of multi-throttle-slices was established. Followed is a practical example for the computation of the equivalent thickness of multi-throttle-slices, compared the computed results with that simulated by ANSYS. The results show that the computation method of equivalent thickness of multi-throttle-slices is accurate enough.
