Sensitivity Analysis And Optimization Design Principle Based On The Material Parameters From The Injury Test Of Dummy Legs

Road traffic accident has become a worldwide problem,which seriously affects the safety of human life and property.Therefore,people pay more attention to the safety of the automobile nowadays.As the basic and fundamental measure to test and evaluate the car safety,vehicle crash test can detect the car's ability to protect the crew when the collision occurs.The risk of the crash test determines that the test can not rely on a real person,so the crash test dummy is born.The crash test dummy model is based on the appearance and size of the real person,and the internal parts of dummy are equipped with different sensors to collect the collision data,so as to provide the evaluation data for the vehicle crash safety.People usually focus on the damage for head and chest when it comes to car's ability to protect crew.However,in the car crash accident,the leg injury can not be ignored.Although the lower limb injury is not fatal,the recovery process is long.Once becoming disabled,the wounded would suffer a blow.The purpose of this paper is to establish a new finite element dummy leg model,which aims to improve the dummy leg structure,so as to improve the speed and precision of the model.In this paper,three different methods are used to establish the finite element dummy model.The first one is to replace the leg bones and knees with a beam element and a torsion spring.The second is the combination of multi rigid body dummy model,with less rigid parts to simulate the main structure of the leg dummy.The third is mainly based on the finite element method and the actual leg structure,this thesis establishes a new finite element model of the dummy leg and performs knee calibration on the leg model.The results show that the design of the third leg model has a higher precision of knee calibration,so it is identified as the main research object of this paper.For the sake of the uncertainty of the structure parameters.There are many ways to study the uncertainty problem.In this paper,the sensitivity analysis and interval optimization method are proposed,which can describe the structural model more objectively and accurately.Sensitivity analysis is the basis of optimal design which can study the largest variables of impact on target function and is an effective tool for optimization.The interval optimization related mathematics method,nonlinear equations and nonlinear equations have a relatively mature solution.For a class of linear equations,the coefficient matrix of the basic components of unrelated,there is a large number of solving methods.When the interval is optimized,the objective function and the constraint function are interval.In this paper,sensitivity analysis is carried out on the dummy leg main structure parameters,then select high sensitivity parameters to do interval optimization,so that the dummy leg structure can be more reasonable and accurate.The study can provide some reference for automotive passive safety crash simulation analysis.