Study On The Coupling Mechanism Between Highly Nonlinear Solitary Waves And Elastic-plastic Bodies

Solitary wave,as a good information carrier,is widely used in ihe field of nondestructive testing.In recent year,one-dimensional particle chains composed of clastic particles or granular crystals have been widely used for proportion characteristies of waves.One-dimensional particle chain is a special medium,it makes the particle chain produce a stress wave after being hit,which is called highly nonlinear solitary wave.This kind of wave has strong stability,good controllability and good information transmission function,which makes it possible to be applied to the field of nondestructive testing.By analyzing the feedback information brought by the flight time and amplitude curve of rebound solitary wave,the purpose of structural detection is achieved.The researech contents are as follows:1.Research on the motion trait of one-dimensional particle chain:the propagation characteristics of solitary waves in one-dimensional particle chain and the interaction between particles in one-dimensional particle chain are studied,from Hertz’s contact law,the relationship between the contact force and the compression of two particles after contact is derived.Using Hertz’s contact law and Newton’s second law,and differential equations of each particles in the particle chain are deduced.Analyze the contact interaction between particles in one-dimensional particle chain and the characteristics of solitary wave propagation in one-dimensional particle chain.2.Study on the coupling effect between one-dimensional particle chain and elastic-plastic body:Based on the elastic-plastic contact model established by Stronge,considering the strain rate effect caused by plastic deformation of materials in the contact zone,and Hill’s equilibrium equation of plastic zone of spherical shell,and considering the dynamic yield conditions of dynamic yield stress and strain rate effect,the relationship between contact force and compression in each deformation stage is derived,and then the elastic-plastic contact characteristics are described to solve the contact problem between one-dimensional particle chain and elastic-plastic body.Differential equation of motion of the coupling effect between the last one of the particle chain and the elastic-plastic body is derived,and numerical solution adopts fourth-order Runge-Kutta method to explore the sensitivity of solitary waves to the elastic modulus and strain rate coefficient of the elastic-plastic body and the yield stress of the material.3.Study on the coupling effect of one-dimensional particle chain and elastic-plastic beam:The contact force and deformation relations of elastic-plastic beam at each stage are obtained through the bending moment equilibrium condition of beam,the orthogonal relation between strain increment and flow criterion and the elastic bending theory,combined with the differential equations of one-dimensional particle chain motion,the complete differential equations of the coupling effect of highly nonlinear solitary waves and elastic-plastic beams are obtained.The fourth-order Runge-Kutta method be used to solve the calculation,analyze the influence of physical properties such as length,thickness and elastic modulus of elastic-plastic beam on rebound wave,and determine the influence of plastic deformation.4.The purpose is to verify the correctness of the numerical calculation results,this chapter uses ANSYS FEM software to simulate the above-mentioned one-dimensional particle chain model,and studies the behavior of propagation and reflection of highly nonlinear solitary waves in one-dimensional spherical particle chain.The whole model consists of 25 spherical particles and a cylindrical magnesium alloy structure.After defining the physical properties of the structure,the finite element mesh is divided and the initial conditions are set and calculated.After comparing the results of finite element calculation with those of solitary wave theory,it verifies the effectiveness of the model,and then in comparison with the previous numerical results,the error of the primary rebound amplitude is 1.5%,and the error of the second rebound amplitude is 3.73%,so the correctness of the calculation results in this paper is verified.In addition,in order to explore the influence of different plastic yield stresses on rebound wave,the finite element calculation of different elastic-plastic materials and one-dimensional particle chain system is carried out.This study investigates the accuracy of the computational results presented in this paper through theoretical deduction and numerical calculations,comparing them with finite element analysis results.It provides a theoretical foundation for utilizing highly nonlinear solitary waves in the nondestructive testing of elastic-plastic materials,thus expanding the practical application prospects for this novel testing method.