Honeycomb Panel Shear Pin Assembly for Reduced Fastener Count

Solution Overview

Problem

The existing methods for securing aircraft floor structures using honeycomb core sandwich panels require a large number of fasteners to accommodate both tension and shear load requirements, which increases installation time, labor, and exposure to environmental stressors, while also being inefficient in reducing the number of fasteners needed.

Innovation Solution

A shear pin assembly is designed to secure to the bottom face sheet of a honeycomb core sandwich panel, engaging a support structure without passing through the top face sheet, thereby reducing the number of fasteners needed and providing sufficient shear resistance by transferring shear forces directly to the support structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If threaded fasteners extend through both top and bottom face sheets to accommodate shear load requirements, then shear securement is sufficient, but the number of fasteners increases and installation time increases

Engineering Contradiction:

Improveshear securementVSAvoidinstallation time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The fastening system is segmented into two distinct types: threaded fasteners that extend through both face sheets for tension load accommodation, and shear pins that extend only through the bottom face sheet for shear load accommodation. This segmentation allows each fastening element to be optimized for its specific function, reducing the total number of fasteners needed while maintaining sufficient shear securement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shear pin assembly extracts the shear-resisting function from the threaded fastener system. By providing dedicated shear pins that engage the support structure and bottom face sheet, the threaded fasteners can be reduced in number since they no longer need to independently handle both tension and shear loads simultaneously.

Inventive Principle:

Principle #2Taking out (Extraction)

2Strength

If a larger number of fasteners are employed to accommodate shear load requirements, then shear securement is sufficient, but labor requirements increase

Engineering Contradiction:

Improveshear securementVSAvoidlabor requirements

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The fastening system is segmented into two distinct types: threaded fasteners that extend through both face sheets for tension load accommodation, and shear pins that extend only through the bottom face sheet for shear load accommodation. This segmentation allows each fastening element to be optimized for its specific function, reducing the total number of fasteners needed while maintaining sufficient shear securement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shear pin assembly extracts the shear-resisting function from the threaded fastener system. By providing dedicated shear pins that engage the support structure and bottom face sheet, the threaded fasteners can be reduced in number since they no longer need to independently handle both tension and shear loads simultaneously.

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If more fasteners extend through the top face sheet, then tension securement is sufficient, but exposure to environmental stressors increases

Engineering Contradiction:

Improvetension securementVSAvoidenvironmental stressors

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The shear pin assembly extracts the shear-resisting function from the threaded fastener system. By providing dedicated shear pins that engage the support structure and bottom face sheet, the threaded fasteners can be reduced in number since they no longer need to independently handle both tension and shear loads simultaneously.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Different fastening elements are applied at different locations with different functions: threaded fasteners are positioned to accommodate tension loads, while shear pins are positioned to accommodate shear loads. This local differentiation optimizes the fastening system by placing each type of fastener only where its specific function is needed, reducing overall fastener count and environmental exposure.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11572907B2Shear pin for panel structural support

Publication Date: 2023.02.07 THE BOEING CO

AI summary

A shear pin assembly for securing to a face sheet of a honeycomb core sandwich panel structure and to engage a support structure, which includes a head member having a first width dimension and a neck section secured to the head member with the neck section having a second width dimension less than the first width dimension. Further included is a flange secured to the neck section with the flange extending in a direction away from the neck section and a pin member which extends from the flange in a direction away from the head member.