Computational Stochastic Structural Analysis (COSSAN)

It is a well known fact that traditional analysis and design procedures of engineering structures neglect the intrinsic, i.e. physical, uncertainties of the parameters and variables, e.g. loading, material, geometrical properties, etc., involved. These procedures are generally labled as deterministic procedures. Stochastic approaches by which, in general, these uncertainties may be treated more realistically are — particularly for dynamic problems — open to criticism with respect to the degree of simplification of the mechanical modeling. In other words, while the load models show a considerable degree of sophistication, in most cases the structural mechanical models are far from reflecting the state of the art. Procedures are generally limited to SDOF or two DOF systems. PΔ effects with large deflections, which are so important, particularly when investigating collapse failure mechanisms, generally cannot be included in the analysis. Moreover, in many cases only second moment properties of the response are provided, which are certainly of limited practical use only for the analyst or designer. It is mainly due to this lack of sophistication of the mechanical modeling, i.e. due to the fact that the mechanical models of the structures for stochastic analysis do not match those which are used in so called deterministic design, that stochastic procedures still lack the recognition they deserve by practicing engineers. Basically stochastic procedures represent a particular way of information processing. While deterministic procedures select “representative” (mean, maximum, minimum, etc.) values to describe the parameters, stochastic methods process the entire information which is available, i.e. instead of arbitrarily selecting one particular value, the entire spectrum of possible values — in terms of probability distributions — is utilized.