System, method, and apparatus for metallic-composite joint with compliant, non-corrosive interface
AssigneeLockheed Martin Corporation
InventorJohn Barnes
Life of this patent
Estimating the term…
Abstract
A metallic-composite joint is formed by inserting a metallic member into a slot of a pi-shaped composite preform. The preform is formed from woven carbon fiber in a binder of resin and may or may not be cured prior to assembly. An inert compliant layer is located between the legs of the preform and the metallic member. The resin binder or an adhesive is used to bond the compliant layer to the preform. The compliant layer has a coefficient of thermal expansion that more closely matches that of the preform. The properties of the compliant layer also avoid galvanic corrosion between the carbon in the preform and the metallic member.
Claims29
A structural assembly, comprising:
- a preform having a slot formed therein;
- a metallic member formed from a metallic material and located in the slot of the preform;
- a composite member formed from a composite material and joined to the preform;
- and
- a compliant member located in the slot of the preform between the metallic member and the preform, the compliant member having a coefficient of thermal expansion that is similar to that of the preform to reduce the risk of separation therebetween when subjected to thermal stresses, such that the compliant member acts as a ductile layer to absorb a greater thermal expansion of the metallic member against a lesser thermal expansion of the composite member as thermal energy is applied thereto.
A joint for dissimilar materials, comprising:
- a preform formed from a composite material and having a pi-shape in cross-section, including a base and legs projecting from the base to define a slot between the base and the legs;
- a metallic member formed from a metallic material and located in the slot of the preform;
- a composite member formed from a composite material and joined to the base of the preform;
- a compliant member located in the slot of the preform between the metallic member and the preform, the compliant member having a coefficient of thermal expansion that is similar to that of the preform to reduce the risk of separation therebetween when subjected to thermal stresses, such that the compliant member acts as a ductile layer to absorb a greater thermal expansion of the metallic member against a lesser thermal expansion of the composite member as thermal energy is applied thereto;
- and wherein
- the compliant member is inert and acts as a barrier to galvanic corrosion that might otherwise occur between carbon in the preform and the metallic member.
A method of fabricating a joint, comprising:
- (a) providing a preform having a slot;
- (b) joining a composite member to the preform;
- (c) positioning a compliant member on a metallic member to form a sub-assembly;
- and
- (d) locating the sub-assembly in the slot of the preform such that the compliant member is located between the preform and the metallic member, the compliant member having a coefficient of thermal expansion that is similar to that of the preform to reduce a risk of separation therebetween when subjected to thermal stresses, such that the compliant member acts as a ductile layer to absorb a greater thermal expansion of the metallic member against a lesser thermal expansion of the composite member as thermal energy is applied thereto.
Dependencies are inferred from the claim text.