Grooved Composite-Metal Rod Joint With Hoop Reinforcement

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Solution Overview

Problem

The challenge is to create a reliable and cost-effective load transfer mechanism between composite and metallic materials, particularly in aerospace applications, where composite materials are expensive to manufacture due to labor-intensive machined metallic parts and complex shapes in joint areas.

Innovation Solution

A method involving forming grooves in both the metallic and composite components, inserting the metallic component into the composite component, and applying a composite hoop reinforcement circumferentially to form a joint, which includes machining and using forming tips to shape the grooves and reinforce the interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional machined metallic parts and complex composite shapes are used for joints, then load transfer reliability is improved, but manufacturing cost and labor intensity increase significantly

Engineering Contradiction:

Improveload transfer reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The joint structure is segmented into distinct functional zones: a metallic component with an external groove, a composite component with an internal groove, and a reinforcement element. These segments are assembled together to create the complete joint, allowing each part to be manufactured separately using simpler, less expensive processes while maintaining overall reliability through their coordinated interaction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a hybrid composite structure combining metallic and composite materials in a single joint assembly. The metallic component provides ductility and toughness, while the composite component provides high strength-to-weight ratio and stiffness. This composite approach enables reliable load transfer while reducing the need for complex machining operations on either material.

Inventive Principle:

Principle #40Composite materials

2Strength

If complex shapes are created in joint areas of composite parts, then load transfer capability is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improveload transfer capabilityVSAvoidjoint area complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The complex joint functionality is achieved by segmenting the structure into modular components with relatively simple individual geometries. The metallic component has a simple external groove, the composite component has a matching internal groove, and they are joined with a reinforcement element. This segmentation avoids the need to create complex monolithic shapes in either component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The joint structure employs nesting where the metallic component with its external groove is inserted into the composite component with its internal groove, creating a nested configuration. The reinforcement element is then placed within this nested structure. This nesting approach achieves complex load transfer functionality through simple, nested geometries rather than complex monolithic shapes.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Productivity

If grooves are formed in both metallic and composite components, then load transfer efficiency is improved, but manufacturing steps increase

Engineering Contradiction:

Improveload transfer efficiencyVSAvoidnumber of manufacturing steps

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The grooves in both the metallic and composite components are formed as preliminary features before the final assembly operation. This preliminary action allows the grooves to be created using optimized processes for each material type, and then the components are simply joined together in a single assembly step, rather than requiring complex post-assembly operations to create the load transfer features.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The grooves act as intermediary features that facilitate the connection between the metallic and composite components. By preparing these intermediary grooves in advance on both components, the actual joining operation becomes a simple matter of fitting the components together, with the grooves providing the mechanical interlock that enables efficient load transfer without requiring additional complex manufacturing steps.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP4241968B1Composite/metal joints for composite rods

Publication Date: 2025.10.22 GOODRICH CORP

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AI summary

A method of forming a joint between a composite component (18) and a metallic component (12) is disclosed. The method includes forming a first groove in an outer surface of the metallic component (12) on a first end of the metallic component. The first groove extends circumferentially on the outer surface relative to a center axis of the metallic component, and the first groove extends radially inward from the outer surface relative the center axis. The method further includes inserting the first end of the metallic component (12) into a first end of the composite component (18). A second groove on the composite component (18) over the first groove of the metallic component (12) such that the composite component (18) extends radially inward into the first groove of the metallic component. A composite hoop reinforcement is then applied in the second groove in a circumferential direction and the composite component (18), and the composite hoop reinforcement are solidified.