Airship Load Patch with T-Tape Attachment
Solution Overview
Problem
Conventional load patches for high-altitude pressurized airships cause significant strain concentrations on the fabric skin, leading to potential tears due to resistance to expansion and changes in atmospheric pressure, making them unsuitable for high-altitude operations.
Innovation Solution
A load patch design featuring a triangularly-shaped body with inelastic filaments sandwiched between elastic sheets and a T-shaped attachment tape that limits contact with the fabric skin, distributing loads radially and allowing transverse compliance to accommodate expansion while preventing lengthwise stretching, thereby reducing strain concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional load patches are adhesively bonded directly to the fabric skin, then attachment strength is improved, but strain concentrations develop around the lamination area causing potential fabric skin tears
Solution Approach 1:
The load patch is divided into multiple discrete components: a triangular patch body, radial reinforcement elements extending from the apex, and a separate attachment loop assembly. This segmentation allows each component to perform its specific function - the patch body distributes loads, the radial elements reinforce stress paths, and the attachment loop secures moorings - while minimizing strain concentrations on the fabric skin by reducing the bonded lamination area to only the essential attachment points rather than a large continuous bonded region
Solution Approach 2:
The load patch employs composite construction combining multiple materials with different properties: the patch body uses woven fabric or laminate materials for load distribution, radial reinforcement elements use high-strength rigid or semi-rigid materials to channel stresses, and the attachment loop uses flexible but strong materials. This composite approach creates a multi-functional assembly that efficiently manages stresses while minimizing the area in direct adhesive contact with the fabric skin, thereby reducing strain concentrations that could cause tears
2Strength
If the entire surface of the load patch is adhesively bonded to the fabric skin to define a lamination area, then load distribution is improved, but resistance to expansion during inflation generates large strains
Solution Approach 1:
Instead of bonding the entire load patch surface to the fabric skin, the invention applies adhesive bonding only at critical locations - specifically at the attachment loop assembly and at key anchor points on the patch body. This partial bonding approach provides sufficient load transfer and distribution while leaving most of the patch and fabric skin unbonded, allowing the fabric skin to expand freely during inflation without resistance from a large lamination area, thus minimizing strain generation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The load patch effectively disperses applied loads and limits strain concentrations along the fabric skin, reducing the risk of tears and enhancing the integrity of high-altitude airships by minimizing the lamination area and distributing stresses efficiently.
Implementation Method 1
a first elastic sheet having a first and a second surface, a second elastic sheet having a first and a second surface
Implementation Method 2
a plurality of inelastic filaments interposed between the first surface of the first and second elastic sheets
Data Source
AI summary
A load patch for attaching concentrated loads to a flexible inflated structure such as a high-altitude airship is stiff in the direction of the applied load so as to carry the load, and is attached to the inflated structure for a very short distance through T-tape so as to minimize strain concentration in the inflated structure due to the stretching of the inflated structure. Since the load patch must be attached for a long length transverse to the load to distribute the applied load, it is transversely compliant to minimize strain concentration in the inflated structure due to stretching of the inflated structure.