Abstract:

Deformation reinforcement theory (DRT) advances stability criterion for elastoplastic structures and suggests effective reinforcement to prevent instability. The core of DRT is the principle of minimum plastic complementary energy (PCE): elastoplastic structures deform trending to the state of minimum PCE, or to take full advantage of their bearing capacities while to minimize the required reinforcement. This principle is rederived and the principle of minimum complementary energy for stable states is given. It is shown that DRT promotes finite element method by revealing the physical meanings of the unbalanced force and the modified Newton-Raphson algorithm. By comparison with the rigid body limit equilibrium method, the engineering significance of DRT is illuminated: the traditional action-resistance system in engineering design is extended to action-resistance-reinforcement system, where reinforcement fully described the difference of action and resistance.

Key words: structural stability, deformation reinforcement theory, elastoplasticity, finite elements