Shell Structure Force Transmission Point CFRP

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Solution Overview

Problem

Current methods for introducing forces into CFRP components are time-consuming, prone to damage, and suffer from corrosive issues and moisture penetration, limiting their strength and industrial scalability.

Innovation Solution

A shell structure with a force application point featuring a metal fitting part with a flat contact surface, braced directly to the CFRP component, allowing for distributed force introduction without adhesives, using press-in elements or screws for high-strength connections, and a cover for moisture protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lamination process is used to integrate connecting elements into CFRP components, then force introduction capability is achieved, but production time increases and subsequent changes are no longer possible

Engineering Contradiction:
Improveforce introduction capabilityVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention applies preliminary action by creating recesses and providing fastening elements (such as press-in nuts or threaded inserts) during the molding process itself, before the component is completed. This allows force introduction capabilities to be pre-established in the CFRP component without requiring time-consuming post-lamination operations. The fastening elements are integrated into the component structure during manufacturing, enabling subsequent assembly operations to be performed quickly and efficiently.

Inventive Principle:
Principle #10Preliminary action

2Strength

If press-in elements or welding elements are used for screw connections in steel or aluminum bodies, then higher strength class is achieved, but contact corrosion and surface pressure restrictions occur with CFRP components

Engineering Contradiction:
Improvestrength classVSAvoidcontact corrosion and surface pressure damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention applies the intermediary principle by introducing a fastening element as a mediator between the screw connection and the CFRP component. Instead of directly applying high surface pressure from a screw to the CFRP material, the fastening element (such as a press-in nut or threaded insert) serves as an intermediate component that distributes the load over a larger area. This intermediary structure enables high-strength screw connections while preventing contact corrosion and surface pressure damage to the CFRP composite material.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention utilizes composite materials by combining CFRP (carbon fiber reinforced plastic) with metal fastening elements that have different mechanical properties. The CFRP provides corrosion resistance and structural integrity, while the metal fastening elements provide the necessary strength and thread formation capabilities. This composite approach allows the system to achieve high strength class screw connections without the harmful effects of direct metal-to-CFRP contact, as each material performs its optimal function.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If threaded holes are created in fixing structures, then force introduction is enabled, but moisture penetration into the component interior occurs

Engineering Contradiction:
Improveforce introductionVSAvoidmoisture penetration
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention applies preliminary action by creating recesses in the CFRP component during the molding process, before assembly. These recesses allow fastening elements to be integrated in a way that minimizes open pathways for moisture. By pre-structuring the component with integrated fastening elements rather than creating threaded holes after manufacturing, the invention reduces the risk of moisture penetration while maintaining force introduction capabilities.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2945836B1Shell structure comprising force transmission point
Publication Date: 2018.06.06 BAYERISCHE MOTOREN WERKE AG
  • EP2945836B1 patent drawingFigure 1

AI summary

The invention relates to a shell structure (1) having a force transmission point (2), wherein a force transmission structure (3, 4, 5) is provided on the force transmission point (2), wherein the force transmission structure (3, 4, 5) has a fitting element (6) comprising a fastening element (7), wherein the fitting element (6) is connected to the shell structure (1). According to the invention the fitting element (6) has a contact surface (6c) having the shell structure (1) and the contact surface (6c) can be clamped with or is clamped with the shell structure (1).