CN-122021214-A - High-speed body impact simulation method based on grid-free smooth particle Galerkin algorithm

CN122021214ACN 122021214 ACN122021214 ACN 122021214ACN-122021214-A

Abstract

The invention relates to a high-speed body impact simulation method based on a grid-free smooth particle Galerkin algorithm, which comprises the steps of establishing a geometric model of a high-speed body and a target plate body, setting the target plate body as a flexible body, adopting SPG to carry out particle dispersion on an area within N times of the diameter of the high-speed body from an impact point to form a high-strain area, adopting a finite element method to divide a grid on an area below N times of the diameter of the high-speed body from the impact point to form a low-strain area, adopting a common node constraint connection between SPG particles and finite element grids, setting the high-speed body as the flexible body, adopting SPG to carry out particle dispersion, adopting a flexible body-flexible body SPG particle contact model between the high-speed body and the target plate body, adopting SPG particles and a finite element grid as a point-surface contact mode, and calculating the generation rate of aerosol in the impact process according to the total mass and kinetic energy change curve of the high-speed body. The full-flow behavior precise characterization of the flexible body impact deformation-material fracture crushing-aerosol conversion in high-speed impact is realized.

Inventors

CUI JINJIANG
YUE QI
CHEN HONGXU
KANG JING
LIAN BING
CHEN HAILONG
WU FEIFEI
CHEN JIACHEN
SU ZIQIANG
HAO YIJIE
DONG YUYANG

Assignees

中国辐射防护研究院

Dates

Publication Date: 20260512
Application Date: 20251229

Claims (10)

1. A high-speed body impact simulation method based on a grid-free smooth particle Galerkin algorithm is characterized by comprising the following steps: establishing a geometric model of the high-speed body and the target plate body; The target plate body is set as a flexible body, particles are dispersed by adopting SPG in a region with the diameter being N times of the diameter of the high-speed body from an impact point to form a high-strain region, and the region with the diameter being N times of the diameter of the high-speed body from the impact point is subjected to grid division by adopting a finite element method to form a low-strain region; Setting the high-speed body as a flexible body, and adopting SPG to carry out particle dispersion; The contact between the high-speed body and the target plate body adopts a flexible body-flexible body SPG particle contact model, and is controlled by the control_SPG; Setting boundary conditions, namely setting boundary conditions on the other sides of the target plate body except the impact surface and the opposite sides of the impact surface, setting an initial speed of a high-speed body to form a certain angle with the impact surface of the target plate body, and setting a calculation domain boundary as a non-reflection boundary condition; Setting calculation parameters and starting simulation calculation; extracting stress distribution, high-speed body speed time-course curve, mass change curve and kinetic energy change curve of the target plate body, and generating animation and stress cloud picture of the impact process; and calculating the aerosol generation rate in the impact process according to the total mass and kinetic energy change curve of the high-speed body.
2.A method according to claim 1, wherein the calculation of the aerosol-generating rate comprises: In the formula, For the time-by-time aerosol occurrence, For the rate of change of the kinetic energy of the high-speed body, Critical energy for aerosol generation, M being the total mass of the high-speed body.
3. The method of claim 1, wherein the target plate body is a 1/4 model of an actual target plate, the 1/4 model symmetry boundary is symmetrically constrained by spc_set, and one sliding degree of freedom perpendicular to the symmetry plane and two rotational degrees of freedom parallel to the symmetry plane are fixed respectively; For the rest of the sides except the impact surface and the opposite sides of the target plate body, SPC_SET is used for fixing constraint, and all six rotation and sliding degrees of freedom are fixed at the fixing boundary.
4. The method of claim 1, wherein the high-speed body uses a Johnson-cook elastoplastic metal model and a Gruneisen state equation and sets an erosion failure threshold; The target plate body adopts an elastoplastic model with fracture properties, an equivalent plastic strain failure threshold and a bond breaking stretch/compression rate are defined, and the target plate body is controlled by an ADD_ EROSION keyword.
5. The method of claim 1, wherein the high speed body has an SPG inter-particle distance of 0.05-0.2mm and the smooth length is 2 times the inter-particle distance.
6. The method of claim 1, wherein the high strain region has an SPG inter-particle distance of 0.05-0.2mm, the smooth length is 2 times the inter-particle distance, and the SPG particles are controlled by the x SECTION _sol_spg.
7. The method of claim 1, wherein the mesh size of the low strain region is graded from inside to outside to 0.5-2 mm.
8. The method of claim 1, wherein the contact setting between the high speed body and the target plate body comprises setting a penalty function to 1.0 to 1.2 times the respective Young's modulus, setting a dynamic friction and static friction coefficient to 0.1, and closing a sliding scale factor and a maximum surface contact scale factor.
9. The method according to claim 1, wherein the setting of the calculation parameters comprises: Calculating an adaptive time step based on CFL conditions: Wherein, the As a safety factor, d min is the minimum inter-particle distance, c s is the speed of sound, v max is the maximum particle velocity; Introducing a secondary artificial viscosity term to inhibit oscillation, and carrying out artificial viscosity and stress correction; The global hourglass was set to the Flanagan-Belytschko solid hourglass model.
10. The method of claim 1, wherein the high-speed body is made of radioactive metal and is in the shape of a rod or sphere, and the target plate body is a rectangular plate made of steel.

Description

High-speed body impact simulation method based on grid-free smooth particle Galerkin algorithm Technical Field The invention relates to the technical field of high-speed body impact simulation, in particular to a high-speed body impact simulation method based on a grid-free smooth particle Galerkin algorithm. Background In the fields of aerospace, nuclear facility retirement, national defense engineering and the like, the research of extreme mechanical behaviors caused by high-speed body impact is very important, and the application scene of the method comprises key scenes such as spacecraft protection design, superhard material impact resistance evaluation and the like. Particularly in the field of radioactive materials, the dispersion of aerosols generated by high-speed body impact can seriously affect the environment and personnel safety. When a high-speed body impacts a target, complex physical processes of extremely plastic deformation, dynamic crack propagation, geometric distortion and even phase transformation of materials can be initiated in an ultra-short time (< 0.1 ms). The traditional method faces some challenges aiming at the problems, including grid division by a Finite Element Method (FEM), the problems of grid distortion, singular stress and calculation divergence are easy to occur under the large deformation problem due to the requirement of preset failure criteria, even the problems of negative volume and node stall are caused, the grid is required to be heavily constructed in the calculation process, the calculation efficiency is reduced, and additional interpolation errors are introduced. Limited volume methods (FVM) have difficulty tracking interface changes, and limited difference methods (FDM) have poor adaptability to complex geometries, and none of these processes can be accurately described. In contrast, the gridless Lagrangian algorithm is a good path to solve the high-speed body impact simulation problem, and fully adapts to the large deformation problem by using discrete ions instead of grids. The smooth particle galerkin algorithm (SPG) is a typical representation of this method. SPG simulates material failure through an inter-particle bond connection model, namely when the relative displacement between particles exceeds a threshold value, bonds are broken to form a free surface, and the particles still participate in subsequent kinetic calculation, so that the conservation of mass and momentum is ensured. Compared with the traditional smooth particle fluid dynamics (SPH) method, the SPG is optimized through Euler shape functions and self-adaptive smooth length, and is more suitable for simulation of the crushing process under high strain rate. The algorithm disperses the material domain into particles carrying the properties of mass, speed, stress and the like, and realizes calculation through kernel function interpolation. However, the existing SPG suffers from the problems of limited computational efficiency bottleneck, difficult parameter setting, relatively poor computational stability, and failure to analyze the subsequent aerosol generation of the impact. In order to avoid the problems as far as possible, an effective set of calculation example establishment method and a reasonable calculation parameter set are required to be constructed aiming at a high-speed body impact simulation calculation scene, so that the possibility of occurrence of calculation abnormality is reduced. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a high-speed body impact simulation method based on a grid-free smooth particle Galerkin algorithm, which solves the technical problem that the whole flow behavior of flexible body impact and deformation-material fracture crushing-aerosol conversion in the process of impacting a target plate body by the high-speed body cannot be accurately described by the existing method. The technical scheme adopted by the invention is as follows: The invention provides a high-speed body impact simulation method based on a grid-free smooth particle Galerkin algorithm, which comprises the following steps: establishing a geometric model of the high-speed body and the target plate body; The target plate body is set as a flexible body, particles are dispersed by adopting SPG in a region with the diameter being N times of the diameter of the high-speed body from an impact point to form a high-strain region, and the region with the diameter being N times of the diameter of the high-speed body from the impact point is subjected to grid division by adopting a finite element method to form a low-strain region; Setting the high-speed body as a flexible body, and adopting SPG to carry out particle dispersion; The contact between the high-speed body and the target plate body adopts a flexible body-flexible body SPG particle contact model, and is controlled by the control_SPG; Setting boundary conditions, namely setting boundary conditions