The Parallel Algorithm Of Extended Multiscale Finite Element Method For Coupling Thermal-mechanical Problems

As a typical problem in cross-discipline,coupling thermal-mechanical problems exist in the fields of aerospace,automobile manufacturing,and electronic circuits widely.It is a process in which the stress field and the temperature field affect each other.To clarify the state and response under the influence of temperature and stress,coupling thermal-mechanical problem of heterogeneous materials needs to be computed and analyzed.However,most of the existing computing-programs are based on the finite element method and adopt the continuity assumption,which cost a lot of time and computer resources to solve the large-scale coupling thermal-mechanical problem of heterogeneous materials.Based on the Extended multiscale finite element method(EMs FEM)and parallel model,this paper combines the domain decomposition algorithm and the Portable,Extensible Toolkit for Scientific Computation(PETSc)computing library,transplants the PETSc library to EMs FEM,and develops the EMs FEM parallel algorithm.The key research content of this paper can be divided into two parts:Firstly,the parallel algorithm for EMs FEM static analysis is developed.To realize the load balance of each core,the domain decomposition algorithm is used to divide the units into each process that ensures each process to perform parallel-computing synchronously.To reduce the communication overhead between the cores,the PETSc parallel-computing library is transplanted to EMs FEM and the PETSc solver is used to solve the linear FEM equations directly.The basic process includes the reading of input files,the formation of macro/micro finite element equations,the introduction of boundary conditions and the parallel solving of equations.The accuracy and efficiency of the EMs FEM parallel algorithm are verified by three numerical examples of fixed beam bending,concentrated force on the fin cooler,and cylindrical stretching.Secondly,the parallel algorithm for steady-state coupling thermo-mechanical analysis of EMs FEM is developed.The accuracy of parallel algorithm of EMs FEM for coupling thermalmechanical problems is verified by two numerical examples of the fin cooler and the cylinder.By running different cores to calculate and compare calculation times,the results show the high efficiency of the algorithm.The results also show that using the domain decomposition algorithm and the parallel mode of PETSc library can achieve the balance of load.At the same time,it has a good parallel efficiency that ranges from 0.62 to 1.