Example

 

A simple example shows how to use this post-analysis toolkit. Figure1 shows the modeling.

 

Figure 1  An example for the Eigen Movement

 

A rigid body is supported by four spring-dampler forces. The left side two springs (Spring1 and 2) are stiffer than the right side (Spring3 and 4).

All spring are set with Y direction. The stiffness of the left side is stiffer than the right side. Therefore, the displacement of the left side will be smaller than the right side.

After the eigenvalue analysis, we can check the 4th mode moves along the Y-axis with absolute eigen vector and eigen animation result.

 

Figure 2  The absolute eigenvector result on the OUT file

 

The marker 1, 2, 3, and 4 are selected in order to check the displacement on the Eigen Movement Dialog. The marker 1, 2, 3, and 4 is connected the Spring 1, 2, 3, and 4, respectively.

Therefore, we can expect followings

1.  The displacements of the left side two markers (the marker 1 and 2) are the same.

2.  The displacements of the right side two markers (the marker 3 and 4) are the same.

3.  The displacemet of the left side is smaller than the right side.

 

The below figure shows the result. And the expectations are confirmed.

 

Figure 3  Result of the Eigen Movement