Stefan Jendo

Multicriterion reliability-oriented optimization of structural systems by stochastic programming

Papers deals with multicriterion reliability-oriented optimization of truss structures by stochastic programming. Deterministic approach to structural optimization appears to be insufficient when loads acting upon a structure and material properties of the structure elements have a random nature. The aim of this paper is to show importance of random modelling of the structure and influence of random parameters on an optimal solution. Usually, quality of engineering structure design is considered in terms of displacements, total cost and reliability. Therefore, optimization problem has been formulated and then solved in order to show interaction between displacement and a total cost objective function. The examples of 4-bar and 25-bar truss structures illustrate our considerations. The results of optimization are presented in the form of diagrams.

Multicriterion Discrete Optimization of Space Trusses with Serviceability Constraints

The paper deals with discussion of discrete optimization problem in structural space-truss design. The cross-sectional areas of truss bars are taken as design variables. A catalogue of circular hollow sections for truss bars and a numbers of the series of types of cross-sections of bars are taken as discrete decision variables. The stress, local stability, displacement (design) constraints as well as technological and computational constraints are taken into account. The mass of truss bars including mass of joints as well as exploitation and maintenance costs are chosen as optimization criteria. A numbers of the series of types of cross-sections of bars t is also taken as a criterion of optimization. The sets of non-dominated (efficient) and compromise (Pareto optimal) solutions and the preferable solution for space truss are found. The results are presented in the form of diagrams.

Multicriterion Optimization of Large Scale Mechanical Systems

The paper deals with discussion of optimization problems in engineering structural design. The following questions are discussed: continuous or discrete optimization, single-or multicriteria optimization, one-or multilevel optimization. The paper is illustrated with example of multicriterion discrete optimization of large scale truss systems.

Multiobjective Reliability-Based Optimization of Plastic Frames

We consider here a general formulation of multicriteria reliability-based optimization where two mutually conflicting criteria, minimum cost (weight) and maximum reliability of structural system, are used. There exist a few procedures which allow us to handle the multicriteria optimization problem. One of them is transformation of the multicriteria problem to a single-criterion optimization problem using the utility function method. The paper is illustrated by an example of plastic frame optimization with random parameters (loads and material properties).