by zhouxinwei » Tue Aug 15, 2017 1:16 am
Assuming we are using node-face constraint formulation (TrngFaceNodeBondList) to model the interaction between the steel sheet and concrete.
To clarify: my previous comment (slave nodes moved to master surface) applies when the user specifies SlavesOnSurface when defines TrngFaceNodeBondList.
With keyword MasterSlaveWithRotations, the formulation allows a certain gap between slave nodes and master surface. This is the one we suggest to use in the following example.
In reality, let's image a concrete slab sits in XY plane, a steel sheet (thickness of T) sits on top of it, we apply an evenly distributed force on the top surface of steel sheet along XY plane in shear.
In MARS model, if the steel sheet is modeled as shell elements, the mid-surface is T/2 away from the concrete. When we directly apply forces on the shell elements, these forces are applied on the nodes which are on the mid-plane of the elements. As a result, this gives the correct resultant force, however, to account for the eccentricity effect (and resulting moments), we need to create another load list to apply moments on the shell elements. Keyword NodalLoadList can be used to apply force or moment. It's recommended to make the steel sheet as master surface, and concrete nodes as the slave nodes.