Problem description

Custom Connections may be applied between two plate sections in the (green) Staged Construction mode in PLAXIS 3D. A plate section is referred to here as an individual (selectable) plate part found after Intersection.

When dealing with more than two plate sections (connected with a Custom Connection) the user should be aware of the relevance of the order of selection of the Custom and the Reference part (see also related item). The first plate section selected becomes the Custom part and the second selected plate section becomes the Reference part. Now also see the example figure below. In this example the Custom and Reference part have been applied/selected in an inconsistent manner. As a result an unexpected local fixity between the plate sections (meaning no free rotations or translations allowed) is introduced since the nodes at this location are merged.

Figure 1. Custom and Reference part have been defined in an inconsistent manner

Solution

When using the 3D2012 versions try to apply the Custom Connections in a consistent manner. After your calculation always inspect your Output results. Note from the figure above that when observing the Connection (the yellow line) in Output it directly becomes clear that the Connection is not continuous indicating the aforementioned problem is present. In this case go back to the Input program and reverse the Custom and Reference part. This may be done conveniently by using the “invert connected parts” option from the pop up menu after right clicking on the Connection.

Note that this behaviour has been improved in the 3D2013 versions, so for the relatively simple case as shown here the Custom Connection is always applied in an expected manner (regardless of the way Custom and Reference part have been applied). For more complex cases however we recommend the user carefully inspects the Output results to see if the Custom Connections have been applied as expected.