Study On Parallel Computing Method Of3-D Seismic Response Analysis Of Large-scale Structure

With the development of science and technology and the rapid expansionof economies, a large number of large-scale structures are built around theworld. There are two technical challenges in the earthquake response analysisof these large-scale structures:(1) the number of elements of the finite elementmodels of these structures and the number of degrees of freedom are so huge;(2) these structures are affected by higher order mode and a large number ofequations are needed to better analyze the structural response. In order to solvethe problems of these structures accurately, parallel computing tools can beused. In this dissertation, seismic response analysis of large-scale structure isstudied based on the application of parallel computing techniques. The researchmainly includes the following aspects:1. Current research of all kinds of domain decomposition methods arestudied, and C/C++programs of some methods are compiled. The merits anddemerits of each method are summarized, and the applicable scope of eachmethod is also studied.2. A variety of domain decomposition algorithms are analyzed, and thenthe advantages and disadvantages of the commonly used algorithms aresummarized.3. Sub-structure analysis method is studied carefully, and correspondingC/C++program is compiled where ANSYS is used for the preprocessor to getthe structural stiffness matrix and load matrix. Then static analysis of thesimple cantilever beam which is divided into two substructures is solved usingsubstructural parallel computing algorithms. Detailed study of this methodprovides the basis for subsequent study.4. BDD (Balancing Domain Decomposition) method is studied detailedly.BDD method is a substructure method, and the structure is split into severalnon-overlapping sub-structures. The node of each sub-structure is divided intointerface boundary nodes and the remaining internal nodes. Firstly, Staticcondensation of the degree of freedom in each sub-structure is carried out, and then equations of degree of freedom of the interface nodes are formulated.Secondly preconditioning conjugate gradient method are applied using BDDpreconditioner to solve the equations. Information between interface nodesmust be exchanged in the solving process. Finally displacement and stress ofeach node can be acquired.5. Based on domain decomposition algorithm, parallel computing methodsof static and dynamic analysis of large-scale structure are researched. Thisdomain decomposition has been implemented within a finite element code forlinear implicit transient dynamic analysis, and time integration is performedusing Newmark-β constant average acceleration method. The example showsthat the compiled program can be used for parallel computing analysis oflarge-scale structure.6. Based on domain decomposition algorithm, parallel computing methodsof static and dynamic nonlinear analysis of large-scale structure are alsoresearched. In the nonlinear equations, Newton-Raphson iteration method isused within each load increment or each time step, and conjugate gradientmethod is used for the corresponding iterative calculation in each iteration stepof the Newton–Raphson. Based on ADVENTURE the corresponding dynamicnonlinear parallel computing program is also compiled, and the example showsthat it can be used for large-scale dynamic nonlinear analysis of large-structure.7. Parallel computing analysis of Pantheon in Itali is implemented usingthe above methods on massive parallel processors. The finite element model ofthis structure is divided into about1,329,027four-node tetrahedral elements.The results show that about eleven minutes are needed when96processors areused.