Question

Fiber hinges seem to introduce artificial flexibility to the model, though hinges are a plastic mechanism which should not influence elastic behavior. Is it possible to implement fiber hinges without introducing softening?

Answer

This softening behavior may be attributed to calculation of the fiber-hinge response curve, which proceeds directly from the axial response of individual section fibers. During linear response, fiber elasticity is added to element elasticity, causing softening. To avoid elastic softening, users should divide frame members at hinge locations such that a smaller segment is positioned along the hinge length. A large area property modifier should then be assigned to small sections, using the Assign > Frame > Property Modifiers menu.