Novel Concepts for Constraint Treatments and Approximations in Efficient Structural Synthesis

The paper presents some new concepts for efficient treatment of large number of constraints. The ideas are based on finding effective ways of reducing the number of active constraints without degrading thei r overall behavioral characteristics or a ltering the essential nature of the original design problem. This has led to a set o f t hree distinct and new concepts which are discussed here. The paper first presents a generalized concept of "dial -inu form of constraint approximation, which can supply a hierarchy of conforming constraint approximati on -- forms for increasing conservativeness and/or accuracy. It contains two tuning parameters, which can be used to control the quality o f the constraint approximations for most structural types (truss, frame, panel, reinforced, etc. ) and finite elements (membrane, bending, shear, plate, shell, etc.) of interest. Second, the paper presents a concept of partitioning the mixed constraint set according to their types into distinct subsets. This allows control of the constraint behaviors in a logical manner. Third, the paper introduces a concept of e ffectively collapsing the constraints which occur in packets of high concentrations. A d eterminate truss, an indeterminate truss and a thin beam are used as examples.

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