Composite Thread Profile for Strength-Preserving Joints
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Solution Overview
Problem
Existing methods for creating threaded joints in composite materials weaken the material by cutting fibers, and current solutions fail to maintain material strength when the joint is subjected to stress in either tension or compression.
Innovation Solution
A threaded joint design featuring a symmetrical thread profile with specific geometric features, including crest and root regions with rounded transitions and flat flanks, which maintains material strength and allows for the use of adhesives or lubricants to enhance the joining process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional thread cutting is used to create threaded joints in composite materials, then threads can be formed for joining, but the fiber continuity is disrupted and material strength is weakened
Solution Approach 1:
The patent extracts the thread formation process from traditional cutting methods and replaces it with a forming approach using a mandrel. The mandrel is inserted into a hollow composite part, and material is deposited around it to form threads, thereby eliminating the harmful cutting action while preserving fiber continuity and material strength.
Solution Approach 2:
The patent replaces the mechanical cutting system with a material deposition system. Instead of removing material through cutting, the invention uses a mandrel-based forming process where material is deposited around the mandrel to create threads, substituting a destructive mechanical process with a constructive forming process that maintains material integrity.
2Adaptability or versatility
If threaded joints are created in composite materials, then joining capability is achieved, but the joint strength under tension and compression stress is insufficient
Solution Approach 1:
The patent changes the geometric parameters of the thread profile to optimize performance. Specific parameters including thread angle, crest radius, root radius, and flank geometry are carefully controlled to ensure the threaded joint can withstand both tensile and compressive loads effectively while maintaining material strength.
3Shape
If fiber cutting is performed to create threads, then thread geometry is achieved, but fiber continuity is lost and structural integrity is compromised
Solution Approach 1:
The patent extracts the mandrel from the final product and replaces the cutting-based thread formation with a deposition-based approach. The mandrel serves only as a temporary form during manufacturing, allowing threads to be formed without cutting or disrupting the fiber reinforcement continuity in the composite material.
Data Source
AI summary
An optimized thread profile (140) for joining composite materials is presented. This thread profile (140) maintains a certain material strength when used as part of a composite threaded joint (101). The thread profile (140) comprises a repeating pattern of four components: a crest region (150), a first flank (162), a root region (170) and a second flank (164). The thread profile (140) is symmetrical, that is, the dimensions of the four components do not change throughout the length of the thread profile. The crest (152) has a flat profile and the root (172) has a rounded profile. When a shaft (120) is affixed to a joining shaft (110) using this optimized thread profile (140), the flat profiles of the crest (152) of the shaft (120) and corresponding rounded profiles of the root (172) of the joining shaft (110) create a gap to accommodate a substance such as an adhesive or a lubricant. Similarly, the flat profiles of the crest (152) of the joining shaft (110) and corresponding rounded profiles of the root (172) of the shaft (120) create a gap to accommodate a substance.