1451. Algorothhmic Mass-Factoring of Finite Element Model Analysis

Paper

Abstract

In preliminary design of military aircraft finite element structural analyses are utilized for the redundant structure inherent in low aspect ratio wings. The finite element model analyses pose a problem for current weight prediction techniques. These models are not total representations of the ‘real structure’. Models are generally only skeletal representations of primary load carrying fully effective stiffness material. The theoretical weight, of the modelled optimized structure, may represent only 30% of the actual structural weight. Single factor and normal parametric multipliers do not appear adequate to accurately predict the ‘actual’ or design’ weight. A new viable technique is the algorithmic mass factoring approach applied at the ‘element’ level. General, modelling, design, and manufacturing criteria for a structural concept are used in deriving each algorithm. The algorithms then employ geometry, material properties, and optimized sizing for computation of a set of weight increments to be added to each element. Each increment represents a non-optimum structural weight not included in the idealized model. This technique can be easily programmed to interface with any automated finite element model – structural optimization and analysis program (FEM-SOAP) enabling ‘real-time’ weights data for predicting ‘actual’ or ‘design’ weight and for subsequent structural analysis cycles.