What Boundary Condition to be applied for a Plane surface to remain as plane after loading..?

[AravindanS]

Hi all. I am Aravindan. I'm facing an issue in a ABAQUS problem. "I have a cube with a spherical empty shell in middle. So I took 1/8th model as shown in figure. So, along the three faces where sphere is cut, I have applied symmetry BC. But on the remaining three sides, I dont want the surface to undergo inclination while loading. i.e., I want the surface to remain planar as parellel to original surface; but it must be allowed to move along X due to tension effect and along Y and Z because of poisson effect. So I cannot use any symmetry BC. I have also tried selecting those planes and gave All rotations BC = 0; But it took it for each element and made the element to remain parellel.. But the elements-to-elements on that surface got offset as shown"

- So this is my problem. I want my surface to remain planar, even after loading. What BC can i apply..??? Is there any option to provide customized BC like all nodes in that plane has to undergo equal displacement along one direction...??

 

[AravindanS]

In equation, I selected the all the nodes on the plane except central node and named them as a set-1. Then I select the unselected node as Set-2. from interaction->select equation-> co-efficient -1 for set1 and 1 for set2; and gave my DOF of interest, and got the result plane remaining as plane.

But is it possible that, can I ask ABAQUS to dynamically select the node with average displacement on that plane (without that constraint) as Masternode(Set-2),simulaneously solve the model with constraints(like step-1, find the node with avg displacement in tha tplane; step-2 Select that node as master node in equation)so that I hope i can get justify my method of equation. Is there any way to solve this.??