You could create the frame with square legs, and create the collagen in the shape of the deformed legs. Create Bonded Contact between the collagen and the legs and use Contact Step Control to set the bonded contact to be dead in step 1 and be alive in steps 2 and 3.
Step 1 ramps on a force on the tip of each leg to bend it toward the center.
Step 2 maintains that force and makes the contact come alive.
Step 3 ramps that force to zero. The legs will spring back and pull the collagen with them.
You could simulate the frame without the collagen and apply the end forces, then export the deformed shape for use in SpaceClaim to construct the shape of the collagen.