Optimization of truss structures by a stochastic method

This paper presents an original stochastic method of optimization (PGSL) for optimum design of truss struc- tures. PGSL (Probabilistic Global Search Lausanne , developed at the Swiss Federal Institute of Techn ology at Lausanne) has been interfaced with a finite element code, the n applied and tested on several size optimization p roblems of plane truss structures. This method uses a probability distribu tion function (PDF) to sample the search space and select the best struc- ture. A PDF represents the probability of finding a good solution at any given point in the search dom ain. The better solu- tions are more likely to be found in the neighbourh ood of good solutions; hence, probabilities are inc reased in regions where good solutions are found. The main advantage of this method is to avoid the sensitivity analysis and to converge to the global optimum.