Optimization of a Totally Fiber-Reinforced Plastic Composite Sandwich Construction of Helicopter Floor for Weight Saving, Fuel Saving and Higher Safety

Abstract

The application of fiber-reinforced plastic (FRP) composites as structural elements of air vehicles provides weight saving, which results in a reduction in fuel consumption, fuel cost, and air pollution, and a higher speed. The goal of this research was to elaborate a new optimization method for a totally FRP composite construction for helicopter floors. During the optimization, 46 different layer combinations of 4 different FRP layers (woven glass fibers with phenolic resin; woven glass fibers with epoxy resin; woven carbon fibers with epoxy resin; hybrid composite) and FRP honeycomb core structural elements were investigated. The face sheets were composed of a different number of layers with cross-ply, angle-ply, and multidirectional fiber orientations. During the optimization, nine design constraints were considered: deflection; face sheet stress (bending load, end loading); stiffness; buckling; core shear stress; skin wrinkling; intracell buckling; and shear crimping. The single-objective weight optimization was solved by applying the Interior Point Algorithm of the Matlab software, the Generalized Reduced Gradient (GRG) Nonlinear Algorithm of the Excel Solver software, and the Laminator software. The Digimat-HC software solved the numerical models for the optimum sandwich plates of helicopter floors. The main contribution is developing a new method for optimizing a totally FRP composite sandwich structure—due to its material constituents and construction—that is more advantageous than traditional helicopter floors. A case study validated this fact.

Modal Analysis of Optimized Trapezoidal Stiffened Plates under Lateral Pressure and Uniaxial Compression

“…Its results show that the trapezoidal stiffeners are more cost-effective than open section ribs, e.g., the cost savings can reach 40%, although the higher strength steel is 8-10% more expensive. These procedures can be also applied to many other problems in engineering practice; for example, for composite sandwich structures [6,21] and plastic composite sandwich construction in aircraft structures [7].…”

“…Structural optimization is a good basis not only for achieving weight and cost savings but also for helping designers select the most suitable structure version. Papers [6,7] elaborated a new optimization method for a totally FRP composite construction in which the single-objective weight optimization was solved by applying the Interior Point Algorithm of the Matlab software, the Generalized Reduced Gradient (GRG) Nonlinear Algorithm of the Excel Solver software, and the Laminator software. The Digimat-HC software solved the numerical models for the optimum structure.…”

Numerical Studies on Failure Mechanisms of All-Composite Sandwich Structure with Honeycomb Core under Compression and Impact Loading Conditions

“…The honeycomb sandwich structure can achieve high material utilization efficiency and reduce structural weight under the condition of meeting the design requirements of strength and stiffness [ 1 , 2 , 3 , 4 , 5 , 6 ]. Therefore, it is widely used in aerospace, rail transit, shipbuilding, construction industry, etc.…”