Improved Mounting Point Stress Redistribution of Primary Loads in Composite Structures

Innovative concepts and solutions will be developed to improve stress redistribution at the mounting sites of primary loads in laminated composite structures through design modification of the structure and the joints. The best approaches will exploit new developments in materials and processing technology in advanced composites and adhesives, and make ingenious use of the strong anisotropy in stiffness and strength and flexibility in forming optimal structural shapes. Through thickness tapering, edge inclination, changes in ply orientation and stacking sequence, and use of toughened adhesives, composite structural components and adhesive joints will be designed for superior strength, improved performance and load transfer efficiency. Recent innovations in mechanical fastening of metallic componeents will be considered for use in composite structures. Highly efficient and versatile analysis methods will be developed for rapid evaluation of severe interlaminar stresses in edge regions, and to obtain optimal design parameter values that achieve weight savings and/or strength enhancement. Fracture-mechanics-based interlaminar failure criteria will be applied to assure structural integrity under service and fatigue loads. The feasibility of the proposed solutions will be further evaluated on the basis of damage tolerance, long term behavior, maintenance and cost considerations.