Composite Tube Exhibiting Large Deformation under Bending

Abstract

Polymer matrix composites provide high specific strength and stiffness. However, their brittleness has prevented them from structural applications that require large deformation. One such application is the cross tubes of helicopter landing gears, which, until now, are solely made of high-grade aluminum alloys. This article shows that with strategic placement of fibers at proper orientations in different layers, it is possible to fabricate composite tubes that exhibit large deformation when subjected to bending loads. A composite tube has been designed, fabricated, and tested. This composite tube was able to support the same load and exhibit large deformation as a high-grade aluminum 7075-T6 tube with similar dimensions. Rationale for the strategy of stacking sequence is presented.