Corrugated Composite Fastener Element for Bending Stiffness
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Solution Overview
Problem
Fastener elements made of fiber-composite materials face limitations in bending stiffness due to shear forces caused by bending moments, which reduce their ability to transmit loads effectively.
Innovation Solution
The fastener element features a corrugated structure with angled side walls and connection parts that reduce in height towards the load area, maximizing tension in continuous reinforcement fibers and minimizing shear forces by optimizing the load path, thereby enhancing shear and bending stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a corrugated structure is used to increase bending stiffness, then bending stiffness is improved, but shear forces between fibers increase which limits the bending stiffness
Solution Approach 1:
The side walls of the corrugations are designed with varying height along the longitudinal direction, creating a gradient structure that changes the shear distribution. This parameter variation optimizes the balance between bending stiffness and shear force reduction, allowing the fastener to withstand bending moments more effectively while minimizing fiber shear
Solution Approach 2:
The fastener element uses fiber-reinforced composite material with specifically oriented reinforcement fibers that extend continuously through the corrugated structure. This composite construction allows the material to resist both bending and shear forces by utilizing the anisotropic properties of the fiber composite, where fiber orientation is optimized to carry tensile loads while the matrix resists shear
2Weight of moving object
If the fastener element is made lightweight using composite material, then weight is reduced, but resistance to bending moment and shear forces is compromised
Solution Approach 1:
The corrugation height is varied along the longitudinal direction rather than being uniform, creating an optimized weight distribution. The side walls have maximum height at the support region and reduce towards the load application point, minimizing material usage where bending moments are lowest while maintaining structural integrity where needed
Solution Approach 2:
High-strength fiber-reinforced composite materials are used to achieve high specific strength (strength-to-weight ratio). The continuous fiber reinforcement provides exceptional tensile strength to resist bending moments, while the lightweight composite matrix keeps the overall weight low compared to traditional metallic fasteners
Data Source
Figure 1a~1c
Figure 2a~2c
Figure 3
AI summary
The invention relates to a fastener element (1) fixed at one axial end region (3) with the machine part (2), with a load (F) acting at the other axial end region (4) in a load area (5), wherein the fastener element (1) comprises a plurality of base parts (6) extending in the longitudinal direction (L) and having the load area (5) and connected to each other by corrugations, said fastener element being made of a composite material comprising continuous reinforcement fibers (15) at least partly extending from the machine part (2) to the axial end region (4) remote from the machine part. The height (H) of the corrugations (7) is substantially constant along a first extension (Li), the load area (5) is arranged along a second extension (L2)in which the height (h) of the corrugations is reduced and becomes zero.