A THEORY OF NO-TENSION DISCRETIZED STRUCTURAL SYSTEMS

The paper deals with an idealization of masonry walls, modelled as a no-tension system, and has three purposes: accomodating in the constitutive law the very essential features of a specific class of materials; exploiting the constitutive simplicity in a unifying theory for a category of boundary value and limit analysis problems; providing a basis for robust and mathematically sound solution procedures suitable for preliminary design. Assuming a piecewise linear approximation of the yield surface in the stress space it is shown that the discretized boundary value problem is governed by extremum properties which reduce its solution to quadratic programming. The basic pair of extremum theorems are shown to generate the (static and kinematic) limit theorems, which reduce the problem of determining collapse states and collapse mechanisms to linear programming. Thus the essential features and pattern of the theory of structural plasticity are recovered in the present context of nondissipative, path-independent (holonomic) structural models. © 1990.