# In SDT, what are the boundary conditions for a plate that is simply supported if &fcy; represents the rotation of the transverse normal about an in-plane axis and w is the transverse deflection?

In SDT, what are the boundary conditions for a plate that is simply supported if &fcy; represents the rotation of the transverse normal about an in-plane axis and w is the transverse deflection?

(a) w=0,$\frac{\partial w}{\partial n}$=0

(b) w=0,&fcy;=0

(c) w=0,$\frac{\partial w}{\partial n}$≠0

(d) w=0, Mnn=0

I have been asked this question during an interview.

This interesting question is from Shear Deformable Plate Model in division Bending of Elastic Plates of Finite Element Method

by (185k points)
selected by

The correct answer is (d) w=0, Mnn=0

Easiest explanation: Plate problems are geometrically similar to the plane stress problems except that plates are also subjected to transverse loads. In SDT, a clamped plate has no deflection and rotation of the transverse normal about any in-plane axis, i.e., w=&fcy;=0. In a simply supported end, rotation is not restricted; thusthe reactive moment is zero, i.e., w= Mnn=0. A free end does not have reactive moment and the shear force, i.e., Mnn=Qn=0.

+1 vote
+1 vote
+1 vote
+1 vote
+1 vote
+1 vote
+1 vote
+1 vote
+1 vote