Composite Stringer Pull-Off Capacity via Perpendicular Laminate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Designing stringers with desired weight and performance characteristics is challenging, often resulting in increased complexity and manufacturing costs, and may require additional stringers to achieve desired performance, which can reduce the ability to withstand forces pulling the stringer away from attached structures.
Innovation Solution
A structural system comprising a composite elongate member with a channel and composite structures oriented perpendicular to the surface, which increases the pull-off capacity by attaching a portion of the stringer to the structure, using a filler structure that conforms to the channel's shape and has matching Young's modulus characteristics to the elongate member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single stringer is used with desired weight, then weight is reduced, but performance characteristics such as pull-off capacity are insufficient
Solution Approach 1:
The stringer is divided into a flange portion and a web portion that are selectively attached to the skin panel, allowing independent optimization of each segment's weight and strength characteristics while achieving desired overall performance
Solution Approach 2:
The stringer utilizes composite material construction with specific fiber orientations (0 degrees and 45 degrees) to achieve high strength-to-weight ratio, enabling the single stringer to meet both weight reduction and pull-off capacity requirements
2Strength
If additional stringers are added to increase pull-off capacity, then strength is improved, but device complexity increases
Solution Approach 1:
By segmenting the stringer into flange and web portions with different attachment configurations, the design achieves enhanced pull-off capacity through optimized load distribution rather than adding more stringers, thereby reducing structural complexity
Solution Approach 2:
The invention introduces dimensional variation through the angled (45 degrees) web portion and multi-directional fiber orientations, enabling enhanced strength characteristics without increasing the number of stringers, thus avoiding complexity increase
3Strength
If stringer design is optimized for performance characteristics, then pull-off capacity is improved, but manufacturing cost increases
Solution Approach 1:
The segmented design allows standardization of flange and web portions that can be manufactured separately and assembled, potentially reducing manufacturing cost while maintaining optimized performance characteristics
Solution Approach 2:
By optimizing fiber orientation parameters (0 degrees and 45 degrees) and material composition, the design achieves desired pull-off capacity with cost-effective material usage, avoiding over-engineering
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An apparatus comprises a composite elongate member (402) having a side (403) configured for attachment to a surface (426) of a structure (404) , a channel (428) on the side (403) extending along a length of the composite elongate member (402), and a number of composite structures (431) configured for placement in the channel (428) and configured to attach a portion of the side (403) of the composite elongate member (402) to the structure (404). The number of composite structures (431) has layers (432) oriented substantially perpendicular to the surface (426) of the structure (404) and is configured to increase a capacity of the composite elongate member (402) to withstand forces that pull the composite elongate member (402) away from the structure (404).