Research Of Multi-scale Modeling Method Based On Mutlti-point Constraints

The size of large structure is huge, but its damage often begins at the node details. In order to satisfy both the overall model of computational efficiency and the node details the calculation precision of traditional, single dimension finite element analysis needs to be improved. Because of the existing single dimension finite element modeling method can’t meet the requirements of efficiency and accuracy at the same time, Multi-scale Modeling method in structure has been more and more attention. In this paper, parallel consistent multi-scale model set up by using the multipoint constraint method. Considering the shortage of the existing interface connection methods, the paper puts forward a revised multi-scale interface connection method and attempt to deduce the coupling connection interface node displacement equation. Realize the multi-scale connection between different units, using ABAQUS finite element software for example verification and comparison and analysis, which proves the rationality of the method in this paper. The specific research results are as follows:Put forward the revised multi-scale interface connection methods are put forward. Analysis of the limitations of using the principle of the coupling nodes ’ displacement coordination method alone and using the theory of the equal coupling nodes’ energy coordination method alone. The revised proposed multi-scale connection methods, Interface connection node displacement and deduces the basic equation, implements the plane beam- plate unit and the multi-scale space beam and entity unit connection. With rectangular section as an example, this paper gives specific expression multi-scale connection equations.Multi-scale numerical simulation of the model based on the correction method. The multi scale model and the multi scale model of the beam and solid element are analyzed respectively. By analyzing the influence of the number of connecting points at the interface points on the accuracy of the correction method, the error variation trend of the multi scale mo del with different connection points is presented. Introduce several commonly multi scale coupling methods, and then analyze the multi scale model of different working conditions by the example of a cantilever beam element. Compared the stress and plastic development of different coupling methods, and pointed out the advantages of the different methods.The rationality and feasibility of the method is proved by comparing with the fine element model. The numerical simulation of the multi-scale model based on the finite element software ABAQUS. Connection method of example, interface node number divided into research and comparative analysis of different connection methods. Using ABAQUS finite element software, the method of numerical example verification, thr ough comparing with the entity unit model, proves the rationality and feasibility of this method. Introduces several commonly used method of multi-scale coupling and cantilever beam element, for example, has carried on the comparative analysis under differ ent working conditions. On the basis of entity unit, comparing the stress changes of different coupling method and plastic development situation, the limitations of the different methods are pointed out, and the superiority of this method.Multi scale model analysis of frame structure based on modified method. Establish the frame structure multi-scale model by the modified method and try to analysis the multi scale frame structure by modal analysis and static elastic plastic loading analysis and dynamic analysis. Compare the dynamic characteristics, calculation time, stress change of key parts, plastic development situation and other indicators of the multi scale model, the fine model and the macroscopic model in order to further prove the accuracy and efficiency of the multi scale model.