Mcdonnell Douglas Corporation

The Boeing Company

Stephen Lewis Guymon

Brian Koorosh Hamilton

Ahmed A Hassan

Gregory E Dockter

Thu N Vu

Jian Li

Murray J Hines

A disbond resistant multi-laminate composite product is provided having, a first member; a second member of composite material bonded to the first member; a third member of composite material bonded to at least the second member and being so positioned and arranged such that when the second and third members are stressed at least a portion of the third member will have higher stress than the adjacent second member. The third member preferably has a terminal portion adjacent the second member in which terminal portion the strain energy release rate is higher than in the adjacent second member when the second and third members are stressed. The second and third members are preferably so positioned and arranged such that the third member initiates delamination from the second member before the second member initiates delamination from the first member when the first, second and third members are under stress. A stress level indicator is preferably associated with the third member to measure the stress levels in the third member.

Disbond resistant composite joint and method of forming

An airfoil member () includes a geometric morphing device (). The geometric morphing device () has an inflatable member (). The inflatable member () has an exterior wall () and multiple inflated states. The exterior wall () includes a layer with one or more fibers embedded therein. The exterior wall () controls size, shape, and expansion ability of the geometric morphing device ().

Fiber matrix for a geometric morphing wing

A composite member having increased resistance to delamination includes a reinforcing wrap of fiber-matrix composite material which is encircled about the member so that the edge surfaces of the member are covered by the wrap. The wrap includes fibers which are oriented from about &minus;60&deg; to about &plus;60&deg; relative to the direction along which the reinforcing wrap is wrapped about the member. The fibers of the reinforcing wrap impart increased third-axis or Z-direction strength at the edges of the member where interlaminar tensile stresses are greatest.

Composite member having increased resistance to delamination and method of making same

The present invention relates to an improved helicopter rotor system including a contoured flexure strap having a simplified geometrical configuration. The flexure strap serves to join the rotary hub assembly with the rotor blades and is formed of fiberglass. The primary load carrying fibers of the flexure strap preferably extend in the same direction as the spanwise axis of the flexure strap in order to withstand the centrifugal forces acting on the strap. The inboard end portion of the flexure strap includes two separate ends, with one of the ends extending in a vertically upward direction and the other end in a vertically downward direction. This allows the ends of flexure straps positioned on opposite sides of the rotary hub assembly to overlap one another and be retained in place by a single pin and bolt assembly. A cloth wrap of composite matrix material surrounds portions of the flexure strap to provide redundancy which prevents the fibers in the flexure strap from delamination when subjected to forces arising during operation of the helicopter.

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Mesa, AZ, United States of America

Stephen Lewis Guymon