Patent ID: 6254812
Filing Date: 2001-07-03
Classification: B29C,B29K,B29L,Y10S

Abstract:
A method of forming a composite sine wave spar having a central sine wave web having at least one side and opposing spar caps, comprising the steps of:(a) making a female mold having a forming surface contoured to the desired shape of at least one surface of the sine wave spar;(b) at least partially filling the female mold with an uncured, castable RTV rubber material;(c) lowering a rigid substructure into the female mold to at least partially displace the uncured RTV rubber material so that the RTV rubber material forms to the contour of the interior of the female mold to define the contour of a compliant forming tool mold surface and at the same time forms around at least a portion of the rigid substructure;(d) curing the RTV rubber material to form a compliant forming tool having a compliant covering around at least the portion of the rigid substructure, the covering being a high density elastomer having a durometer hardness of about 75 shore A and being able to withstand elevated temperatures and pressures suitable for curing resin matrix composites in an autoclave supported by the rigid substructure for maintaining dimensional tolerances on the surface of the compliant forming surface;(e) laying up a composite material over the compliant covering of the tool on the mold surface;(f) placing additional tools in a cooperative relationship with the compliant forming tool having the compliant covering wherein the assembled set of tools define the dimensions of the composite sine wave spar; and(g) using the assembled set of tools following step (f) to consolidate and cure the composite material at elevated temperatures and pressures in an autoclave to form the composite sine wave spar to a predetermined dimensional tolerance.