Inversion Identification Method And Software Programming Of Finite Element Material Model And Parameters For Post-foundation Relationship Of Anti-collision Structure

Reasonable pile foundation relationship is the key to ensure that anti-collision structure can play a role in road safety accidents.The research on how to select the appropriate material model and how to calibrate the parameter model is the focus of pile foundation research.In view of the shortcomings of the current research on material model and parameter inversion identification of pile foundation with anti-collision structure,a new inversion identification method is studied in this paper.This method can not only complete the selection of material model,but also calibrate the selected material parameter model.Then,the shortcomings of the anti-collision structure soil material model are explored,and the soil model which meets the needs of impact load analysis is studied.Finally,the rapid modeling method of material model is studied,and an effective inversion recognition tool is developed,so as to realize the integration and automation of inversion recognition method.The main contents of this paper are as follows:1)Research on double-layer optimal inversion identification method based on collision test.According to the shortcomings of the inversion identification method of pile foundation relationship of anti-collision structure,The Dynamic Time Warping distance algorithm is taken as the objective function,and then combined with the intelligent optimization algorithm(LSSVM?PSO?GA et al.),A double-layer optimal inversion identification method for material model parameters is proposed.This method has the following three innovations:on the basis of the test,the actual situation of large deformation,large strain and large rotation of pile foundation with anti-collision structure is fully considered.The Dynamic Time Warping distance algorithm is used to measure the similarity between the practical physical experiment and the finite element simulation model,and the amplitude,phase and shape errors of the two curves are considered synthetically.In the inversion method of material model and model parameters,the coupling between material model and parameters is considered,and the optimal material model and parameters can be obtained by inversion of the two parameters.Based on the real vehicle collision test data,the double-layer optimal inversion identification method can be used to invert and evaluate the material models and parameters of pile foundation with large deformation,large strain and large rotation under impact load.2)Study on primary selection and parametric method of soil material model.According to the literature and test reports,from the point of view of mechanical properties and similarity theory of pile foundation relationship of anti-collision structure,the mechanical properties of soil need to consider strain rate effect and strain hard-softened effect.Therefore,Five kinds of soil material models which meet the requirements are selected from the existing LSDYNA material models.In order to make the double-layer optimization inversion process of multiple material models and parameters more systematic and efficient,an automatic parametric modeling method based on*.dyn binary file is proposed.Based on the original finite element model and the external program written by MATLAB language,the finite element model can be parametrized according to the experimental scheme in order to improve the efficiency of inversion analysis and provide a feasible method for software programming.3)Research on double-layer inversion recognition tool of material model and parameters.Based on the double-layer optimal inversion identification method of collision test,the theoretical research of five material models and parametric methods selected preliminarily is carried out.On the platform of Matlab,the inversion identification software of finite element material model parameters of pile foundation with anti-collision structure is developed.4)Verification of inversion identification method and application of tools.By using the research methods and tools,the concrete problems of pile foundation relationship of anti-collision structure are applied.Through verification and analysis,the maximum error of the inversion result is 2.58%,and the inversion method has high accuracy.In the process of inversion analysis,according to the number of parameters and the upper and lower bounds of the material model,the arrangement table of the experimental scheme can be created.Then according to the parametric modeling method,the software automatically modifies the finite element model parameters according to the table and calculates them.Then the time history data are quantitatively analyzed,and then the target parameters are inversely identified,and the optimal model MAT 272 and parameter ro=1.514e-9,fc=0.09855 of the five material models are obtained.The theoretical modeling and platform construction of the inversion method can provide a theoretical and application basis for a series of problems of material model and parameter calibration,and provide research ideas for perfecting the essential safety construction of road anti-collision structure.