CFRP Pipe-to-Metal Assembly Bonding Without Thermal Peeling

Solution Overview

Problem

The existing manufacturing method for bonding carbon fiber reinforced plastic (CFRP) pipes with metal parts using an adhesive faces issues with peeling due to thermal expansion of the metal parts when heated, leading to a weakened bond.

Innovation Solution

A method where the adhesive is heated internally within the CFRP pipe using a heat source, such as hot wind, without directly heating the metal part, reducing thermal expansion and ensuring a strong bond between the CFRP pipe and the metal part, which may have a higher thermal expansion coefficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the metal part is heated to harden the adhesive, then the adhesive bonding is achieved, but the metal part expands due to thermal expansion causing adhesive peeling

Engineering Contradiction:

Improveadhesive bonding strengthVSAvoidmetal part dimensional stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The heating process is segmented into two distinct phases: first heating the CFRP pipe to cure the adhesive, then heating the metal part separately to achieve its desired shape. This segmentation prevents simultaneous heating of both components, eliminating the thermal expansion issue while maintaining adhesive bonding strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The CFRP pipe is pre-heated and the adhesive is cured before the metal part is heated. This preliminary action ensures the adhesive is already bonded when the metal part undergoes thermal expansion, preventing peeling during the heating process.

Inventive Principle:

Principle #10Preliminary action

2Shape

If the metal part is heated for shaping, then the desired metal part geometry is achieved, but the adhesive peels off due to thermal expansion

Engineering Contradiction:

Improvemetal part geometryVSAvoidadhesive bonding strength

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The heating process is segmented into two distinct phases: first heating the CFRP pipe to cure the adhesive, then heating the metal part separately to achieve its desired shape. This segmentation prevents simultaneous heating of both components, eliminating the thermal expansion issue while maintaining adhesive bonding strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The CFRP pipe is pre-heated and the adhesive is cured before the metal part is heated. This preliminary action ensures the adhesive is already bonded when the metal part undergoes thermal expansion, preventing peeling during the heating process.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the adhesive is heated through the metal part, then the adhesive cures properly, but the metal part expands causing bonding failure

Engineering Contradiction:

Improveadhesive curingVSAvoidbonding precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Instead of heating the adhesive through the metal part, the invention inverts the heating approach by heating the CFRP pipe from its own side. This allows the adhesive to cure through thermal conduction from the CFRP pipe without subjecting the metal part to high temperatures that would cause expansion and bonding failure.

Inventive Principle:

Principle #13The other way round (Inversion)

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

This approach effectively inhibits adhesive peeling and allows for a suitable bond even with metal parts having higher thermal expansion coefficients, reducing manufacturing costs and ensuring a stable assembly.

Implementation Method 1

By a heat source provided in the pipe, a target area is heated without interposing the metal part, the target area being located radially interior to the adhesion area and located on an inner circumferential surface of the pipe

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

since the heat source is provided in the metal part, the metal part is expanded due to a heating of the adhesive

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS11305494B2Manufacturing method of assembly

Publication Date: 2022.04.19 FUTABA IND CO LTD

AI summary

In a manufacturing method of an assembly, the assembly including a metal part and a pipe, the pipe including a material containing a resin, an adhesive is first adhered to an outer circumferential surface of the pipe and a metal part covering at least a portion of an outer circumferential surface of the pipe. Here, an area to which the adhesive is adhered on the outer circumferential surface of the pipe is defined as an adhesion area. Next, by a heat source provided inside the pipe, a target area is heated without interposing the metal part. The target area is located radially interior to the adhesion area and located on an inner circumferential surface of the pipe.