MATLAB: What does deflection mean in Structural Mechanics PDE Toolbox

Question

Let us consider a rectangular structure of length L under strain (x-direction) is elongated by ∆L.

a) Is deflection in this case ∆L, ∆L per L or its bending?

b) If left and right edges of the rectangle are stretched outward, should I use Dirichlet Boundary condition on top and bottom edges or

Neumann Boundary condition on the botton edge.

c) I could export the mesh and solve PDE. How do I plot deflection in horizontal and vertical cuts of the structure?

Thanks in advance.

Answer 1

a) Results output from PDE Toolbox contains Displacements wstruct array ith ux, uy, and uz as fields, these values are displacement from the reference state. These values are sort to (in 1-D) in each direction at each node.

b) You need to decide what BCs represents the physical problem. If you are modelling streaching by pulling of the rectangle with lateral edges free to deflect the just don't assign any BCs on them. In addition you can fix left end and then apply the Dirchlet BC on the right end to simulation pulling, otherwise your model is not fully constrained for rigid motion.

c) Refer to interpolateDisplacement function to get the displacement at you desired locations.