Metal–Organic Matrix Composite Assembly with Blind-Hole Force Distribution
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Solution Overview
Problem
The assembly of metal and organic matrix composite material parts, particularly in components like rocket engine combustion chamber jackets, is often inadequate, leading to unsuitable force distribution and potential bending deformations.
Innovation Solution
A structure where a metal fastening element is fastened to a metal part, sandwiching a second connecting portion of the organic matrix composite material, with blind holes configured to enhance force absorption and distribution, using additive manufacturing techniques to form the fastening element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional assembly methods are used to join metal and organic matrix composite parts, then the assembly can be manufactured, but the force distribution is inadequate and bending deformations occur
Solution Approach 1:
The connecting portion is divided into multiple functional zones: a first zone for force transfer, a second zone with blind holes for additional anchoring, and a third zone for stress distribution. This segmentation allows each zone to handle specific mechanical loads, improving overall force distribution and preventing bending deformations in the composite material.
Solution Approach 2:
The connection structure extends into the thickness dimension of the composite material by creating blind holes that penetrate through the connecting portion. This three-dimensional approach distributes forces across multiple planes and depths, rather than relying solely on surface-level attachment, thereby improving force distribution and mechanical strength.
2Weight of moving object
If the connecting portion is made thinner to reduce weight, then weight is reduced, but the area for absorbing forces is reduced and bending deformations increase
Solution Approach 1:
By creating blind holes that extend through the thickness of the connecting portion, the structure gains additional force absorption capacity in the depth dimension. This allows the connecting portion to maintain reduced thickness (weight reduction) while the holes provide extra surface area for force distribution and anchoring, preventing bending deformations.
Solution Approach 2:
The connecting portion incorporates a porous structure with blind holes that increase the internal surface area available for force absorption. This porous architecture allows the material to maintain low weight while providing extensive surface area for stress distribution and mechanical interlocking with the fastening element.
3Strength
If the connecting portion is made thicker to increase stiffness, then bending deformations are reduced, but the weight increases
Solution Approach 1:
The connecting portion is segmented into multiple zones with different thicknesses and functions. The first zone maintains adequate thickness for force transfer, while the second zone with blind holes provides stiffness through the hole structure rather than uniform thickness. This segmentation achieves the required stiffness without uniformly increasing the thickness and weight of the entire connecting portion.
Solution Approach 2:
The connecting portion utilizes a composite structure combining solid material regions with hollow blind hole regions. This composite architecture provides high stiffness-to-weight ratio, as the blind holes create moment of inertia that resists bending while removing material that would otherwise add weight, achieving stiffness without proportional weight increase.
4Strength
If multiple fastening elements are used to improve force distribution, then the assembly strength increases, but the complexity of the assembly structure increases
Solution Approach 1:
The connecting portion is segmented into multiple zones that can accommodate multiple fastening elements at different locations and depths. This segmentation allows force distribution across multiple attachment points without requiring a complex overall structure, as each zone independently handles local loading while contributing to global assembly strength.
Data Source
AI summary
The invention relates to a piece comprising a first metal part and a second part made of an organic matrix composite material, in which the first part has a first connecting portion and the second part has a second connecting portion, the second connecting portion having at least one blind hole, the second connecting portion being totally or partially sandwiched between the first connecting portion and a metal fastening element, the fastening element being fastened to the first part on a portion other than the first connecting portion and extending into the at least one blind hole, whereby the first part and the second part are fastened to one another.