Author(s)

PETR PROCHAZKA, MARTIN VALEK

Abstract

In this paper, design of trusses supporting a protective wall is discussed. The wall is assumed as sufficiently bearable and fully distributes the load caused by explosion. The problem of the assessment is narrowed to the optimal design for minimum overall mass of the trusses. The reason why the problem of such a protective system is often focused on the optimal shape of trusses is the fact that their members may be considered as a system of springs, which are a suitable means of dissipating energy induced by the effect of load due to explosion. The explosion is initiated in space or directly on the surface of the wall. In our case, vertical walls are considered in 2D; simple generalization of the proposed procedure described below can lead to the optimization of trusses that are curved both in the plane and in space. The algorithms put forward can be applied well for these generalized cases of geometry of the trusses. For various load scenarios, depending on the center of explosion, the optimal shape of truss columns are found using a nonlinear programming, based on the extended Simplex method. An important circumstance is the introduction of buckling effect in the compressed members. The joints are fixed in the plane of the truss and the joint connections are selected in such a way that the minimum mass of the whole truss is attained. The approach leading to the optimal shape is briefly described. It is taken into account that the optimal structure of the truss is achieved exclusively for a statically determinate structure, which always exhibits better results than the indeterminate one. Several typical examples accompany the proposed theory.

Keywords

protective walls, reinforcing trusses, overall mass optimization, nonlinear programming