STIFFNESS ASSOCIATED WITH QUASI-CONCENTRATED LOADS

This paper analyses the effect on their associate displacements of qua si-concentrated loads like those used frequently for stiffness or work measurements. The use of point forces is widely extended when testing structures, and is the common way of applying external loads. Strictl y speaking, these loads do not act at a point: they spread over a very small area on the surface, acting as quasi-concentrated loads. Displa cements are computed on the basis of linear elasticity, and their depe ndence on the contact area is shown explicitly. The results are applie d to the three point bending of beams and to the numerical modelling o f concentrated loads. The paper closes with some practical recommendat ions for computing the displacements.