The analysis fails with an error that parts of the structure is isolated. How do I fix the problem?
The reason for this erroor is usually that some members are not connected they way you they may appear to be.
To see what portions of the model is isolated, consider the illustration below (displayed by the program directly after the error occurs). The disconnected parts of the model using different colours; ideally, everything should be green.
Note: The above illustration may not be visible if you have 3D rendering enabled. If so, disable 3D rendering by click the 3D button in the picture toolbar.
To explain the principle at work here, consider the following example of two beams:
|The beam elements appear to be connected at node 2, but the analysis fails with an error that suggests that parts of the model is isolated from the rest.|
|Changing the graphics options to not draw elements continuous (i.e. stopping them a short distance away from connecting nodes, reveals that beam 1-3 is not connected to node 2.|
|In this case, the top beam was entered as 1-2-3 (instead of 1-3) and is connecting at the common node.|
To correct the problem, change the input for beam 1-3 to 1-2-3. You can also use the split beam elements at intersections in the beams input toolbar to detect the error at node 2 and then appropriately split beam 1-3.
The above is a simple example using beam elements. The principle applies equally to shell and solid finite elements.
Tip: During the input phase it helps to keep the graphics options set to not draw elements continuous.