OS-E: 0180 3-Point Bending using RBODY

Demonstrates RBODY which is used in this nonlinear large displacement implicit analysis involving contacts using OptiStruct.

Figure 1. FE Model with Loadcases and Loadstep

Model Files

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

The model file used in this example includes:


Model Description

This model consists of a steel beam resting on two steel supports and crushed from the middle using another steel cylinder. Sliding contacts are defined between the cylinders and the steel beams. The cylinders are defined as RBODY and the centroid nodes are defined as the reference node, on which the load and boundary conditions can be applied. A load of 500N is applied on the centroid node (reference node) of the big cylinder, the big cylinder can move only in the x direction and the two small cylinders are constrained in all the DOFs. Here a nonlinear implicit analysis is run.

The shell element properties are:
FE Model
Steel Beam and Cylinder
First order shell elements
The MAT1 material properties are:
Steel Beam and Cylinder
Young's Modulus
210 GPa
Poisson's Ratio
Initial Density
7.9 x 10-6 kg/mm3


Figure 2 shows the deformed shape of the steel beam after it is pushed down by the cylinder.

Figure 2. Deformed Shape of Steel Beam
Figure 3 shows the stresses in the rigid bodies after the load is applied.

Figure 3. Stress on the Rigid Body as Zero