Hat Stringer Closeout Fitting Reinforcement
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Solution Overview
Problem
Hat stringers in structural components, such as aircraft, face reduced load-carrying capacity due to run-out trims and additional holes for vent systems, leading to structural integrity issues and increased manufacturing complexity.
Innovation Solution
A closeout fitting for hat stringers comprising a cover and insert that couples to the stringer's surface, limiting torsional and bending deformations and providing a vent connector to maintain structural integrity and simplify the coupling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a run-out trim is applied to the hat stringer to accommodate structural joint fittings, then the hat stringer can be coupled to other structural components, but the load-carrying capacity of the hat stringer decreases due to reduced structural integrity at the trimmed location
Solution Approach 1:
The closeout fitting is divided into separate components (cover and insert) that can be independently manufactured and then assembled together to form a complete reinforcement structure at the hat stringer terminus
Solution Approach 2:
The closeout fitting combines metal components (cover and insert) with the composite hat stringer structure to create a hybrid assembly that leverages the strengths of both material types - the metal provides reinforcement at the trimmed location while the composite maintains its lightweight properties
2Adaptability or versatility
If additional holes are drilled through the hat stringer to accommodate vent system connections, then the vent path can be established, but the structural integrity of the hat stringer decreases
Solution Approach 1:
The cover acts as an intermediary component that provides vent system connection capability without requiring holes to be drilled through the hat stringer itself, thereby maintaining the structural integrity of the original component while still enabling venting functionality
3Reliability
If multiple tasks are performed to seal the vent path proximate the run-out trim during the coupling process, then the vent path can be sealed, but the time and cost of the larger coupling process increases
Solution Approach 1:
The vent path sealing function is merged into the closeout fitting assembly process itself - as the cover and insert are installed to complete the hat stringer terminus, the vent path is simultaneously sealed, eliminating the need for separate sealing operations and reducing overall process time
Solution Approach 2:
The closeout fitting is designed with pre-configured sealing features that are already in place before installation, so that when the fitting is assembled to the hat stringer, the vent path sealing is automatically achieved without requiring additional sealing tasks during the coupling process
Data Source
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AI summary
A closeout fitting (100) for a hat stringer (50) includes a cover (130) that has a fitting surface (134). The fitting surface is substantially complementary to at least a portion of an outer surface of the hat stringer. The cover is configured to couple against the hat stringer outer surface. The cover also includes a first portion (132) configured to extend across a gap defined in a cap portion of the hat stringer. The closeout fitting also includes an insert (102). The insert includes a first outer perimeter surface (103) that is substantially complementary to at least a portion of an interior surface of a channel defined by the hat stringer. The insert is configured to couple against the channel interior surface proximate the hat stringer closeout portion. The insert and the cover are formed with a suitable stiffness to limit a deformation of the hat stringer proximate the closeout portion.