Week 11 Car Crash simulation

A) TITLE:- Car body frontal crash dynamic explicit simulation using ansys workbench 2019 V3.

B) OBJECTIVE :- To simulate the car body frontal crash motion for analysing different parameters like equivalnet stress , total deformation, equivalent plastic strain etc. through parametric method.

C) MODELING :- The model consisting of a wall and carbody has been imported into the dynamic explicit module.

D) ANALYSIS :-

1)The wall is assigned with structural steel material while the car body is assigned with stainless steel NL material.

2) no contacts has been considered. only te frictionless body interactions are considered.

3) In order to reduce the computational time , two symmetry regions have been considered. first region has considered for wall and second for car body.

4) Meshing of the body is very important in this study. for wall tetrahedron meshing OF 100 mm with patch conforming method is applied. for car body all triangles is used. also the front surfaces which actually come in conatct with wall during crash are finely meshed with 75 mm element size and rest of the body is meshed with 175 mm mesh size.

5)The analysis is carried out for a very short duration of 0.001 sec.

6) In actual practice the car will crash on the wall. but in simulation instead of moving car the wall has given a dispacement of 500 mm towards the car and the car back side surfaces are made fixed. the results are obtained for three different thicknesses of car body through parametric analysis and are summarized below:-

E) RESULTS :-

I)CASE 1 :- CAR BODY THICKNESS 0.3 MM

II)CASE 2 :- CAR BODY THICKNESS 0.5 MM

III)CASE 3 :- CAR BODY THICKNESS 0.7 MM

The results obtained from the parametric analysis are summarized below:-

F) DISCUSSIONS:-

I) The total deformation found to be same ( 720 mm) in all the three cases.

II) the equivalnet stress is found to be maximum with case-3 (2101.3 MPa).

III) As the car body strikes to the wall there is plastic deformation of the body. the equivalnet plastic strain is maximum for case-3 ( 1.33) .

• it can be observed from the results that , with incarease in car body thickness the resistance offered by body for deformation has also increased. hence the equivalnet stress has increased resulting into increase in equivalent plastic strain.
• the results has been found out successfully through parametric study.