Optimal Design of Variable Stiffness Composite Structures using Lamination Parameters

Fiber reinforced composite materials have gained widespread acceptance for a multitude of applications in the aerospace, automotive, maritime and wind-energy industries. Automated fiber placement technologies have developed rapidly over the past two decades, driven primarily by a need to reduce manufacturing costs and improve product consistency...

Structural Performance of Fiber-Placed, Variable-Stiffness Composite Conical and Cylindrical Shells

The use of fiber-reinforced composites in aerospace structures has increased dramatically over the past decades. The high specific strength and stiffness, the tailorability, and the possibilities to integrate parts and reduce the number of fasteners give composites an advantage over metals. Automation of the production process enables large...

Methodological problems in QFD and directions for future development

Application of genetic algorithms to the design of airfoil pressure distributions

NLR participates in the ECARF (European Computation Aerodynamics Research Project) "Optimum Design" project, developing an algorithm for multi-point airfoil design. Within the ECARP project a test case has been defined for two-point design with the aid of well-specified target pressure distributions. It appears that optimization of pressure...

Similarity transformations between minimal representations of convex polyhedral sets

A system of linear inhomogeneous inequalities determines a convex polyhedral set of feasible solutions. It is investigated under which conditions convex polyhedral sets can be represented also by a system that contains equalities as well as inequalities. Different representations of the same convex polyhedral set are related by elementary...

SAMID, an interactive system for aircraft drag minimization studies. Mathematical models and methods

An interactive computer program system has been developed that can be used in aircraft drag minimization studies. It comprises algorithms for choosing the spanwise distributions of lift, pitching moment, chord and thicknessto-chord ratio of lifting elements. The choices are optimal in that they minimize induced plus viscous drag while satisfying...

Critical evaluation of a finite element method for the calculation of transonic flow based on constrained minimization

The method of Glowinski, Periaux and Pironneau for the calculation of transonic flow, which is based on the constrained minimization of a cost function, is critically evaluated for a case in which the transonic small perturbation equation is used. The resulting minimization problem is discretized in finite element form and solved using a...