A mixed finite element solution of contact stresses in meshing gears is investigated with the consideration of coupled thermo-elastic deformation and impact behavior. A simulation procedure of finite element solution ...A mixed finite element solution of contact stresses in meshing gears is investigated with the consideration of coupled thermo-elastic deformation and impact behavior. A simulation procedure of finite element solution of meshing gears is developed. The versatility of the procedure for both numerical accuracy and computational efficiency is verified by numerical analysis of meshing gear teeth.展开更多
According to spatial conjugate principle and theory of elastic contact, a method to pre-control transmission properties and contact mark of point meshing gear is presented, while the deformation of tooth surface is un...According to spatial conjugate principle and theory of elastic contact, a method to pre-control transmission properties and contact mark of point meshing gear is presented, while the deformation of tooth surface is under consideration. A new approach to improve the quality of spiral bevel gear is illustrated emphatically.展开更多
An efficient MPI/OpenMP hybrid parallel Radial Basis Function (RBF) strategy for both continuous and discontinuous large-scale mesh deformation is proposed to reduce the computational cost and memory consumption.Unlik...An efficient MPI/OpenMP hybrid parallel Radial Basis Function (RBF) strategy for both continuous and discontinuous large-scale mesh deformation is proposed to reduce the computational cost and memory consumption.Unlike the conventional parallel methods in which all processors use the same surface displacement and implement the same operation,the present method employs different surface points sets and influence radius for each volume point movement,accompanied with efficient geometry searching strategy.The deformed surface points,also called Control Points (CPs),are stored in each processor.The displacement of spatial points is interpolated by using only 20-50 nearest control points,and the local influence radius is set to 5-20 times the maximum displacement of control points.To shorten the searching time for the nearest control point clouds,an Alternating Digital Tree (ADT) algorithm for 3D complex geometry is designed based on an iterative bisection technique.Besides,an MPI/OpenMP hybrid parallel approach is developed to reduce the memory cost in each High-Performance Computing (HPC) node for large-scale applications.Three 3D cases,including the ONERA-M6 wing and a commercial transport airplane standard model with up to 2.5 billion hybrid elements,are used to test the present mesh deformation method.The robustness and high parallel efficiency are demonstrated by a wing deflection case with a maximum bending angle of 450 and more than 80% parallel efficiency with 1024 MPI processors.In addition,the availability for both continuous and discontinuous surface deformation is verified by interpolating the projecting displacement with opposite directions surface points to the spatial points.展开更多
Deployable high-frequency mesh reflector antennas for future communications and obser- vations are required to obtain high gain and high directivity. In order to support these new missions, reflectors with high surfac...Deployable high-frequency mesh reflector antennas for future communications and obser- vations are required to obtain high gain and high directivity. In order to support these new missions, reflectors with high surface accuracy are widely required. The form-finding analysis of deployable mesh reflector antennas becomes more vital which aims to determine the initial surface profile formed by the equilibrium prestress distribution in cables to satisfy the surface accuracy requirement. In this paper, two form-finding methods for mesh reflector antennas, both of which include two steps, are pro- posed. The first step is to investigate the prestress design only for the cable net structure as the circum- ferential nodes connected to the supporting truss are assumed fixed. The second step is to optimize the prestress distribution of the boundary cables connected directly to the supporting truss considering the elastic deformation of the antenna structure. Some numerical examples are carried out and the simulation results demonstrate the proposed form-finding methods can warrant the deformed antenna reflector surface matches the one by design and the cable tension forces fall in a specified range.展开更多
In applications such as parallel mesh refinement,it remains a challenging issue to ensure the refined surface respects the original Computer-Aided Design(CAD)model accurately.In this paper,an ultralight geometry proce...In applications such as parallel mesh refinement,it remains a challenging issue to ensure the refined surface respects the original Computer-Aided Design(CAD)model accurately.In this paper,an ultralight geometry processing library is developed to resolve this issue effectively and efficiently.Here,we say the kernel is ultralight because it has a very small set of data-structures and algorithms by comparison with industrial-level geometry kernels.Within the library,a simplified surface boundary representation(B-rep)and a radial edge structure are developed respectively to depict the geometry model and the surface mesh,plus hash tables that record the connections between the geometry model and the surface mesh.Based on these data structures,a set of efficient algorithms are developed,which initializes the connection tables,projects a point back to the original geometry,etc.With these data-structure and algorithmic infrastructures set up,the callings of eight well-designed Application Programming Interfaces(APIs)are powerful enough to enable the parallel mesh refinement algorithm outputs a mesh respecting the input CAD model accurately.Numerical experiments will be finally presented to evaluate the performance of the overall parallel mesh refinement algorithm and the algorithms in relation with the developed library.展开更多
文摘A mixed finite element solution of contact stresses in meshing gears is investigated with the consideration of coupled thermo-elastic deformation and impact behavior. A simulation procedure of finite element solution of meshing gears is developed. The versatility of the procedure for both numerical accuracy and computational efficiency is verified by numerical analysis of meshing gear teeth.
文摘According to spatial conjugate principle and theory of elastic contact, a method to pre-control transmission properties and contact mark of point meshing gear is presented, while the deformation of tooth surface is under consideration. A new approach to improve the quality of spiral bevel gear is illustrated emphatically.
基金supported by the National Key Research and Development Program of China (No.2016YFB0200701)the National Natural Science Foundation of China (Nos. 11532016 and 91530325)
文摘An efficient MPI/OpenMP hybrid parallel Radial Basis Function (RBF) strategy for both continuous and discontinuous large-scale mesh deformation is proposed to reduce the computational cost and memory consumption.Unlike the conventional parallel methods in which all processors use the same surface displacement and implement the same operation,the present method employs different surface points sets and influence radius for each volume point movement,accompanied with efficient geometry searching strategy.The deformed surface points,also called Control Points (CPs),are stored in each processor.The displacement of spatial points is interpolated by using only 20-50 nearest control points,and the local influence radius is set to 5-20 times the maximum displacement of control points.To shorten the searching time for the nearest control point clouds,an Alternating Digital Tree (ADT) algorithm for 3D complex geometry is designed based on an iterative bisection technique.Besides,an MPI/OpenMP hybrid parallel approach is developed to reduce the memory cost in each High-Performance Computing (HPC) node for large-scale applications.Three 3D cases,including the ONERA-M6 wing and a commercial transport airplane standard model with up to 2.5 billion hybrid elements,are used to test the present mesh deformation method.The robustness and high parallel efficiency are demonstrated by a wing deflection case with a maximum bending angle of 450 and more than 80% parallel efficiency with 1024 MPI processors.In addition,the availability for both continuous and discontinuous surface deformation is verified by interpolating the projecting displacement with opposite directions surface points to the spatial points.
基金supported by National Natural Science Foundation of China (Grant No.51375360)
文摘Deployable high-frequency mesh reflector antennas for future communications and obser- vations are required to obtain high gain and high directivity. In order to support these new missions, reflectors with high surface accuracy are widely required. The form-finding analysis of deployable mesh reflector antennas becomes more vital which aims to determine the initial surface profile formed by the equilibrium prestress distribution in cables to satisfy the surface accuracy requirement. In this paper, two form-finding methods for mesh reflector antennas, both of which include two steps, are pro- posed. The first step is to investigate the prestress design only for the cable net structure as the circum- ferential nodes connected to the supporting truss are assumed fixed. The second step is to optimize the prestress distribution of the boundary cables connected directly to the supporting truss considering the elastic deformation of the antenna structure. Some numerical examples are carried out and the simulation results demonstrate the proposed form-finding methods can warrant the deformed antenna reflector surface matches the one by design and the cable tension forces fall in a specified range.
文摘In applications such as parallel mesh refinement,it remains a challenging issue to ensure the refined surface respects the original Computer-Aided Design(CAD)model accurately.In this paper,an ultralight geometry processing library is developed to resolve this issue effectively and efficiently.Here,we say the kernel is ultralight because it has a very small set of data-structures and algorithms by comparison with industrial-level geometry kernels.Within the library,a simplified surface boundary representation(B-rep)and a radial edge structure are developed respectively to depict the geometry model and the surface mesh,plus hash tables that record the connections between the geometry model and the surface mesh.Based on these data structures,a set of efficient algorithms are developed,which initializes the connection tables,projects a point back to the original geometry,etc.With these data-structure and algorithmic infrastructures set up,the callings of eight well-designed Application Programming Interfaces(APIs)are powerful enough to enable the parallel mesh refinement algorithm outputs a mesh respecting the input CAD model accurately.Numerical experiments will be finally presented to evaluate the performance of the overall parallel mesh refinement algorithm and the algorithms in relation with the developed library.
