Graduation Design (Dissertation) of Wuhan University of Technology

Automobile suction bumper collision characteristics and protective measures simulation study

School: International Education College

Specialty amp; Class: Auto-mobile 1304

Student name: Chengdu Zhang

Tutor: Weigao Qiao

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Abstract

Statistics show that motor vehicles in the traffic accidents caused by the number of deaths, accounting for the first of all types of deaths. In today's society, the safety of car collision is getting more and more attention. In the process of vehicle collision, the highest probability is the front, first involved in the collision of the front bumper, so the bumper in the collision process of energy absorption characteristics , In order to improve the safety of vehicle collision is of great significance.

In this paper, based on some types of car bumper system size, the use of CATIA three-dimensional modeling function, the establishment of the bumper system and pendulum 3D model. And then through the ANSYS / LS-DYNA grid. And select ANSYS / LS-DYNA for collision simulation. The ANSYS / LS-DYNA front-end processor and solver are used to define the finite element model of the collision. Analyze the dynamic response of the bumper system crash test and evaluate the energy absorption characteristics of the bumper system. The conclusion is consistent with the dynamics of the relevant theory, this paper determines the finite element model of the collision and real reliable simulation results. And then put forward the relevant protective measures to improve the bumper crashworthiness.

The main contents of this paper are as follows:

1) summarizes the development trend of future collision safety technology;

2) introduced the two main research methods of collision safety;

3) Select a car bumper model, and use CATIA to carry out three-dimensional modeling, import ANSYS, use the finite element software ANSYS to define the relevant parameters of the bumper, the grid finite element analysis, and build pendulum model, Determine the constraint and load to simulate the collision;

4) Analyze the results of the simulation, find out the relevant results, the deformation of the bumper, the stress map and the velocity and acceleration of the pendulum hammer, and analyze the bumper failure mode, which can provide scientific basis for the design of the bumper;

5) According to the analysis results to determine the bumper system of the relevant protective measures.

Keywords: collision, simulation, bumper, energy absorption characteristics, crashworthiness, protective measures.

Table of Content

Chapter One Introduction 1

1. 1Purpose and Meaning 1

1. 2Bmper research overview 3

1. 2. 1Introduction of bumper 3

1. 3 Crash test standards 4

1. 4The methods of automobile impact 5

1. 5 Standard of bumper collision protection 8

1. 5. 1 Standard of bumper collision protection in America 8

1. 5. 2The main technical content of ECE R42 (ECE R42) of the European vehicle 10

1. 5. 3 The evaluation criteria of the protective equipment in front of our car GB 17354-1998 11

1. 6 Basic content of research (design) 13

Chapter Two Explicit Nonlinear Finite Element 15

2. 1Finite element overview and development 15

2. 2Calculation of collision collision 16

2. 2. 1The characteristics of the collision process 16

2. 2. 2 Summary of nonlinear finite element 16

2. 3The theory of nonlinear finite element 17

2. 3. 1 The deformation and movement of an object 17

2. 3. 2 Structural discretization and unit dynamics analysis 18

2. 3. 3 Expression of mass matrix 19

2. 3. 4 boundary condition 19

2. 3. 5 Control equation 20

2. 3. 5. 2 momentum equation 21

2. 4Direct Integration 23

2. 4. 1 Implicit integration algorithm 24

2. 4. 2 Explicit integration algorithm 24

2. 5Contact algorithm 25

2. 5. 1 The search rule of contact algorithm 27

2. 5. 2 Areas searching 28