Design optimization of composite plates: Part I - Design criteria for strength, stiffness, and manufacturing complexity of composite laminates

Design criteria are essential for describing the objectives of optimization, Strength, stiffness, and manufacturing are addressed. The mechanical criteria, for strength and stiffness, provide with the magnitude by which the thickness of a given laminate must be scaled in order to just meet all requirements. For first-ply-failure strength, a quartic failure criterion was derived from the quadratic Tsai-Wu criterion, for unsymmetric and symmetric laminates subject to mixed loadsets. For stiffness, maximum displacement constraints can be selectively set on all components and modulus. Combined strength and stiffness control is also analyzed. While developed for single elements, these criteria are also suited for designing entire laminated plates. Assessing manufacturing complexity without undertaking a detailed cost analysis is achieved by an index which interprets numerically qualitative issues such as simple and complex layups. The new manufacturing complexity index takes into account variations in thickness, the steepness of plydrops and the number of zones across a structure.