Fiber-Composite Sandwich Panel Insert for Fastener Load Strength

Solution Overview

Problem

Metal sandwich panel inserts used in aerospace applications are heavy, impacting fuel economy, while conventional plastics lack sufficient compressive strength to withstand fastener loads, leading to potential failure.

Innovation Solution

A fiber-composite sandwich-panel insert with axially aligned fibers in the tubular body and spirally aligned fibers in the tapered head, manufactured via a compression-molding process using a preform charge with a spiral alignment, to withstand both compressive and hoop/tangential stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal sandwich panel inserts are used to withstand fastener loads, then compressive strength is sufficient, but weight increases impacting fuel economy

Engineering Contradiction:

Improvecompressive strengthVSAvoidinsert weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining carbon fiber reinforcement with a polymer matrix to create an insert that achieves metal-level compressive strength while maintaining significantly lower weight. The carbon fiber composite structure provides both the necessary mechanical strength and weight reduction for aerospace applications.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent implements local quality by varying the fiber orientation throughout the insert structure. Axially aligned fibers are used in the tubular body to resist compressive loads, while spirally aligned fibers are used in the tapered head region to resist the combination of compressive axial stress and hoop/tangential stresses, optimizing strength distribution according to local stress requirements.

Inventive Principle:

Principle #3Local quality

2Strength

If axially aligned fibers are used throughout the SPI to address compressive stress, then compressive strength is improved, but the SPI fails to withstand non-axial stresses in the head region

Engineering Contradiction:

Improvecompressive strengthVSAvoidhead region integrity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent implements local quality by varying the fiber orientation throughout the insert structure. Axially aligned fibers are used in the tubular body to resist compressive loads, while spirally aligned fibers are used in the tapered head region to resist the combination of compressive axial stress and hoop/tangential stresses, optimizing strength distribution according to local stress requirements.

Inventive Principle:

Principle #3Local quality

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 fiber-composite insert provides a lightweight solution that maintains structural integrity under fastener loads, preventing local crushing and enhancing fuel efficiency.

Implementation Method 1

manufactured via a compression-molding process

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

compression-molding process

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentUS20250251000A1Composite inserts and manufacturing method therefor

Publication Date: 2025.08.07 ARRIS COMPOSITES INC

AI summary

A fiber-composite sandwich-panel insert is a monolithic structure having a tubular body and a tapered head, wherein an axially aligned bore extends completely through the sandwich panel insert, the monolithic structure comprising a plurality of fibers in a resin matrix, wherein a first group of the plurality of fibers are disposed in the tubular body and have an axial alignment therein, and a second group of the plurality of fibers are disposed at least partially in the tapered head and have a spiral alignment therein.