# OS-E: 0150 Large Displacement Analysis of Chassis

Demonstrates the use of 2D plate (shell) elements with large displacement analysis.

## Model Files

Refer to Access the Model Files to download the required model file(s).

The model file used in this example includes:

SHELL_LGDISP.fem

## Model Description

- Front torsional stiffness
- Rear torsional stiffness
- Vertical bending stiffness

Rail and Cross members modeled with shell elements, 7 are connected via rigid elements.

Displacements (translations and rotations), which are large enough to render small
deformation theory invalid; therefore, the initial stiffness matrix is not suitable to
represent the problem. This may result in either small or large (finite) strains. Large
displacements are those that are greater than the characteristic dimension of the model
(thickness of the beam plate or shell). This is always a nonlinear problem. A typical rule
of thumb, if strains exceed 5%, always switch `LGDISP`=1.

`LGDISP`=1, then the recent stiffness that is taken to the next increment is already updated. Therefore, by having this on, the deformed geometry or an updated stiffness matrix will be taken into the next step.

**FE Model**- Element Types
- CQUAD4

**MAT1**- Young’s Modulus
- 2.1E5 MPA
- Poisson's Ratio
- 0.3
- Density
- 7.85E-9

**MATS1**- YIELD Point
- 350