Research On Mesh Generation Technology And Its Application For Geotechnical Finite Element

With the development of finite element simulation technology,the application of numerical simulation technology has become increasingly widespread,especially in various industries where physical model test and research conditions are not allowed or relatively difficult.In the field of geotechnical engineering,geological phenomena such as faults,stratum pinchouts,and folds often occur in areas with complex structures.In traditional finite element calculation and analysis,complex strata are generally simplified and then calculated by dividing meshes in finite element software,but the final calculation results may deviate from the actual situation.Based on this,it is particularly important to study the finite element mesh generation algorithm that can effectively handle complex strata,so that it is no longer necessary to simplify the strata,and the resulting calculation results are more realistic.Therefore,based on the MATLAB platform,this article developed a quadrilateral grid generation program based on template method.Then,taking common geological profile maps in geotechnical engineering as the object,the grid generation of the entire formation was achieved,and the multi-dimensional quality evaluation of the generated quadrilateral grid was conducted.Then,a certain slope of the Guozigou backup pipeline project on the West Second and Third Line was taken as the research object,Firstly,a quadrilateral grid generation program based on template method is used to divide the slope into structured grids,and the divided grid node data is imported into ABAQUS for finite element numerical simulation;Secondly,use ABAQUS finite element software to establish a model and calculate and analyze it;Finally,two modeling methods were compared,and the program was verified by comparing the calculation results and calculation diagrams,proving its reliability and stability.The main research content of this article is as follows:(1)The partition method of single square parent element is described in detail.The number of nodes and grid template are analyzed;First,according to the node conditions of the four sides of the parent cell,an appropriate number of nodes are generated,and the template method is implemented on the parent cell(a square with a side length of 1),where we save the location information of the nodes and the adjacency matrix.Next,the template method implemented on the parent element is further mapped to any quadrilateral.(2)Based on the method of single square parent cell division,the coordinated division of multiple square parent cells is realized.This paper mainly studies the pretreatment of engineering profile,the alignment of boundary nodes and the scale division.(3)Based on the developed quadrilateral grid generation program,the grid generation of the entire stratum was achieved using common geological profiles in geotechnical engineering as the object,and compared with the grid generated by ABAQUS finite element software,highlighting the advantages of the program in the field of geotechnical grid generation.It can be seen that the grid based on program partitioning is more in line with the actual situation,while the grid based on ABAQUS partitioning is relatively simple.The difference in grid division will directly affect the accuracy of subsequent finite element calculations,leading to errors between the final calculation results and the actual situation,which is not accurate enough.(4)The quadrilateral mesh generated by the program is evaluated in multi-dimension.The grid generated by the program is evaluated qualitatively and quantitatively by three evaluation indicators: grid aspect ratio,deflection coefficient and element twist.Through analysis,it is concluded that the grid generated by the program has high quality.(5)The program calculation results are analyzed from three aspects: stress,strain,and displacement.Through comparison with the control group model,it can be seen that the maximum difference in stress,strain,and displacement between the data file import model that is gridded through the program and the control group model that is automatically gridded by ABAQUS software is 35.4%.The reason for the difference is,on the one hand,whether to simplify the model;On the other hand,it is due to the large mesh size divided by the program,which fails to fully reflect the stress concentration part.However,from the perspective of the magnitude of the difference,meshing through software has considerable reliability,and can greatly save the time of finite element preprocessing.