# inverse problem

## How to study a inverse problem? Know the orbit, solve the constraint condition.

Dear all,

Now I face a noval problem, and I do not know how to deal with it, even cannot begin the first step.

As we know, the formulation of a classical mechanical question  is given the initial condition and the constraint condition, and solve the unknown orbit. Now I face a inverse problem. I know the initial condition and the orbit, and would like to solve the unknown constraint condition.

Is there anyone could give some seggestion, I don't know how to do it. Thanks.

Best.

## Inverse problem in beam bending, elastic-ideally plastic material

Dear iMechanica,

suppose you have a beam with a square cross-section, manufactured from an elastic-ideally plastic material.

Now apply a load that rises linearly in time, but is locally constant along the beam length. Upon sagging, the beam will develop a plastic zone beginning in the top and surface regions at mid-length.
This is the "straight" problem solved in Prager, Hodge: Theory of perfectly plastic solids, publisher: Springer