Embedded Mounting in Thermoplastic Hollow Plates for Smooth Airflow

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Solution Overview

Problem

Existing joining members for resin structures protrude from the surfaces of joined components, disrupting airflow in jet engines when mounted to inner walls.

Innovation Solution

A hollow structure with a thermoplastic resin core layer and skin layers, incorporating a mounting member welded to the core layer's side walls and skin layers, ensuring the mounting member is not exposed from the outer surface, and using spin welding to secure the member within the structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a joining member with a shaft length greater than or equal to the combined thickness of two structures is used, then the joining member can securely join the two structures, but the head and end of the shaft protrude from the surfaces of the joined structures, disrupting airflow in jet engines

Engineering Contradiction:
Improvejoining strengthVSAvoidairflow disruption
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The mounting member is nested within the hollow plate structure, with its columnar body inserted through the hollow plate and welded to the inner surfaces of the skin layers. This nesting approach allows the mounting member to perform its joining function while remaining concealed within the structure, preventing protrusion and airflow disruption.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The mounting member extends in the thickness direction of the hollow plate, utilizing the Z-dimension (depth) rather than protruding in the X or Y dimensions (surface plane). This dimensional reorientation allows secure mounting while maintaining a flat outer surface that does not disrupt airflow.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the mounting member is inserted deeply to ensure secure mounting, then the mounting strength is improved, but the mounting member may become exposed from the outer surface, creating surface irregularities

Engineering Contradiction:
Improvemounting reliabilityVSAvoidsurface flatness
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The columnar body of the mounting member is nested within the hollow plate, with its length carefully controlled to ensure it does not protrude beyond the outer surface of the skin layer. The mounting member is positioned and welded within the thickness of the hollow plate, achieving secure mounting while preserving surface flatness.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The length parameter of the columnar body is optimized to be sufficient for secure welding to the inner surfaces of the skin layers, but not excessive to cause protrusion. This parameter control ensures both mounting reliability and surface flatness are achieved simultaneously.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the mounting member is welded to the side walls of the core layer, then the mounting member is firmly fixed to the hollow plate, but the welding process may affect the structural integrity of the core layer

Engineering Contradiction:
Improvefixing strengthVSAvoidstructural integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The welding parameters (temperature, time, pressure) are controlled to achieve sufficient bonding strength between the mounting member and the core layer side walls, while preventing excessive heat input that could damage the thermoplastic resin structure or compromise the integrity of the cell walls.

Inventive Principle:
Principle #35Parameter changes

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 solution suppresses airflow turbulence and ensures stable mounting by integrating the mounting member within the structure, maintaining a flat surface for airflow and enhancing structural integrity.

Implementation Method 1

the body is welded to the side walls of the core layer

Methodology Applied
Scientific EffectFriction welding: Friction Welding

Implementation Method 2

by frictional heat generated between the hollow plate and the mounting member by moving the mounting member from a first main surface toward a second main surface of the hollow plate while generating relative rotation between the hollow plate and the mounting member

Methodology Applied
Scientific EffectFrictional heat generation: Friction

Implementation Method 3

the resin in the fiber-reinforced plastic is thermally fused and joined to the joining member

Methodology Applied
Scientific EffectThermal fusion: Melting

Data Source

PatentEP4691753A1Hollow structure body and method for manufacturing hollow structure body
Publication Date: 2026.02.11 IHI CORP
  • EP4691753A1 patent drawingFigure 1~2
  • EP4691753A1 patent drawingFigure 3~5
  • EP4691753A1 patent drawingFigure 6

AI summary

A hollow structure (10) includes a hollow plate (11) made of thermoplastic resin in which cells are arranged and a mounting member (30) configured to be securely mounted to an inner wall (4) of a jet engine for an aircraft. The hollow plate (11) includes a core layer (20) having side walls to define cells, a first skin layer (24) laminated on a first main surface of the core layer (20), and a second skin layer (25) laminated on a second main surface of the core layer (20). The mounting member (30) includes a columnar body (31) extending in the thickness direction of the hollow plate (11). A side surface of the body (31) is welded to the side wall of the core layer (20). The body (31) is not exposed from an outer surface of the first skin layer (24).