The “C-triplex” approach to design of CFRP transport-category airplane structures

The quality of CFRP composites is highly dependent on the manufacturing process. Laminate performance is greatly affected by the void and resin fractions. Thicker structures result in lower quality. Thin composite laminates manufactured at high pressures offer best quality. However, impact and damage tolerance, buckling and concentrated stresses for rivets and bolts require redundancy which increases the thickness. Thick laminate structures lower CFRP mechanical properties. Composite laminates have advantage of good surface smoothness and low tolerances. A thin laminate tailored for the specific application with good monitoring system and support for buckling prevention with impact protection offers good solution. The bearing laminate is encapsulated between two sup porting layers with excellent outside tolerances and smoothness rep resenting the C-triplex concept. Inserts are included in the constructions for bolts or rivets. On the bearing laminate a monitoring tissue is installed for load history and structural integrity. The three layers are arranged in a way to house foam that provides support for buckling and thermal insulation. The C-triplex macro panels are bolted to a titanium or aluminum alloy skeleton of the aircraft body. C-triplex panels contain all ducts for the wires, pipes, and plug? necessary for the body interior.