Week 11 Car Crash simulation
Objective: To perform a parametric analysis of a frontal car crash setup and determine the effect of varying the thickness of the model on the equipment stress and total deformation
case 1- 0.3mm
case 2- 0.5mm
case 3- 1.0mm
procedure: create explicit dynamic in Ansys workbench and in engineering data select stainless steel NL and structural steel
stainless steel
structural steel
Import the geometry and check in space claim for any irregularities. Then open Ansys mechanical and rename the component as carbody and wall then assign the stainless steel NL material to the car body and structural steel material to the cases to the wall.
symmetry definition: the entire setup mentioned above represent just half the model the analysis is carried out on a half model to reduce computation time. To get result for the full model, two symmetry regions are defined about which the result of the half model are duplicated.
body interaction - No contact are defined instead a body interaction is introduced, the parameter of which are set as shown below.
mesh - the wall is meshed using tetrahedron and by patch conforming method and carbody by using default mesh size.
Analysis setting - set end time as 1e-3, with max number of cycles as 1e+7, maximum error set to 0.1.
fixed support - Rear surfaces of the car body are provided a fixed support
displacement - wall is provided a displacement of 500mm in Z-direction
parameter definiton - instead of running seperate simulation to get the result, a parametric option is used. The thickness of the car body is set as the input parameter.
for output parameter, the total deformation and equivalent stress and equivalent stress on the car body are set as the output parameter
Run the simulation and result obtained.
Result -
The project interface page appears as below, with a parameter set option. double clicking that option open up the result of the simulation.
the result page from the parameter set page appears below:
case1 - 0.3mm
total deformation - 1042mm
equivalent stress Max - 10764Mpa
equivalent stress car body - 3890.6Mpa
energy conversion plot
case2 - 0.5mm
total deformation - 1037.9mm
equivalent stress Max - 10721Mpa
equivalent stress car body - 4494.6Mpa
energy conversion plot
case3 - 1.0mm
total deformation - 1026.9mm
equivalent stress Max - 10604Mpa
equivalent stress car body - 3784.6Mpa
energy conversion plot
conclusion:
Maximum deformation is developed for case1-0.3mm because of lowest stiffness or rigidity to resist deformation.
Maximum stress is developed for case1-0.3mm because it has minimum thickness so induces maximum stresses due to less resisting area. the model experience the highest von-mises stress when the thickness of the shell is the least.