On the stiffness characteristics of nonmonolithic elastic structures. Part I. Theory

The paper analyses the effect of dry joints on the stiffness characteristics of elastic structures. Particular attention is paid to cases with frictional contact sliding because of the indefiniteness of the solution. For this reason a generalized friction law is introduced, where also the displacement discontinuities at the joints are subjected to conical restraints. This law permits a separation of the dissipative component q and an auxiliary nondissipative dilatational component b of the friction angle u. An analysis based on purely nondissipative friction provides unique solutions and thus a framework for the estimate of solutions corresponding to dissipative friction. The main emphasis is laid upon assessment of bounds for the stiffness characteristics of structures. This constitutes an elastic counterpart and complement to an analogous treatment of the stability of rigid body assemblages [Int. J. Solids Struct. 32 (2) (1995) 203]