Frontal crash simulation of car body

Frontal crash simulation of car body

This explicit dynamic simulation consists of a half-model of a car body (assigned non-linear behavior to observe permanent deformation) crashing into a rigid wall for a given displacement in a fixed time period and parametrizing body thickness to observe variations in the outcomes

Geometry

Fig: Half-model of car body and wall

For material selections, the body is assigned non-linear stainless steel and the wall is assigned structural steel. To observe comprehensive results, the side face and the interacting edges of the surface body of the car are assigned symmetry regions; also for solving purposes, the body interaction between the body and the wall is allowed to be frictionless.

Meshing

Fig: Mesh generation

For comfortable solving and keeping academic limits in mind, the mesh is generated using the following methods:

1. Wall: Patch conforming/tetrahedrons
2. Face sizing for non-interacting faces: size = 350mm
3. Triangular shell elements all over the car body surface
4. Rear faces (fixed) face sizing: size = 350mm

Setup and boundary conditions

The rear faces, side door and roof are assigned fixed support and the rear face of the wall is assigned a displacement of 500mm toward the car. A single time step with an end time of 0.001 sec is assigned. The simulation is parametrized for 3 different thicknesses of the car body shown in the post processing section.

Post Processing

The results, locations of maximum stresses, strain and total deformations are observed as shown below:

Fig: Equivalent stress

Fig: Equivalent strain

Fig: Total Deformation

Fig: Directional deformation

Parametric outputs (all max)

Design Point	Thickness	Total def	Eq stress	Eq strain	Direc. Def (X)
1	0.3mm	938.61mm	8759.8 MPa	0.048	50.36mm
2	0.45mm	937.41mm	8752 MPa	0.048	49.021mm
3	0.6mm	935.57mm	8737.1 MPa	0.048	48.92mm

Conclusion

For increasing thickness, it is observed that the stresses and deformations decrease which contributes to the fact that the overall increase in stiffness leads to increases resistance towards deformation and thus makes it relatively a safer choice from a design point.