Thermoplastic Mechanical Interlock Bonding for Shear-Resistant Joints
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Solution Overview
Problem
The challenge in the automotive, aviation, and shipbuilding industries is to securely bond lightweight materials, such as fiber composites and polymers, which are prone to adhesive failures due to embrittling, making it difficult to control the reliability and increasing manufacturing costs.
Innovation Solution
A method involving a thermoplastic connector that becomes flowable when energy is applied, allowing it to lock into a pre-made or generated opening in a first object, creating a mechanically stable and resistant bond suitable for withstanding shearing forces, while being cost-effective and efficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive bonds are used to bond lightweight materials, then the bond can be light and strong, but the reliability cannot be controlled long-term and manufacturing costs rise
Solution Approach 1:
The patent replaces the chemical adhesive bonding system with a mechanical locking system. A protruding section on the second object extends into an opening in the first object, creating a mechanical interlock that eliminates the need for adhesives. This mechanical system provides both strength and long-term reliability control without the degradation issues of adhesive bonds.
Solution Approach 2:
The bonding system is divided into separate mechanical components: a protruding section on the second object and a corresponding opening in the first object. This segmentation allows for independent manufacturing and assembly, improving reliability control while maintaining bond strength.
2Strength
If adhesive bonds are used to bond lightweight materials, then the bond can be light and strong, but manufacturing costs and time increase due to material cost and slow hardening processes
Solution Approach 1:
The patent replaces the chemical adhesive bonding process with a mechanical insertion process. The protruding section is simply inserted into the opening, eliminating the need for adhesive application, waiting for hardening, and associated quality control steps. This dramatically improves manufacturing efficiency while maintaining bond strength.
Solution Approach 2:
The protruding section and opening are prepared in advance during component manufacturing, so that during assembly, the bonding action is already partially complete. This preliminary preparation eliminates time-consuming steps in the final assembly process.
3Strength
If mechanical bonding methods are used, then the bond is mechanically stable and resistant to shearing forces, but the complexity of the bonding system increases
Solution Approach 1:
The patent applies mechanical interlocking only at the specific location where the protruding section meets the opening, rather than requiring a complex overall bonding system. This localized approach provides shear resistance without increasing overall system complexity.
Solution Approach 2:
The bonding system combines the first object, second object, and connector into a composite assembly where the mechanical interlock integrates these components into a unified structure that resists shearing forces without requiring additional complex bonding mechanisms.
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 method provides a strong, reliable mechanical bond resistant to shearing forces, reducing manufacturing costs and time, and ensuring the bond's stability over time.
Implementation Method 1
causing a flow portion of the thermoplastic material to become flowable and flows relative to the first object and relative to the protruding section; and causing the flow portion to resolidify
Data Source
AI summary
A method of bonding a second object to a first object includes: providing the first object, which includes a thermoplastic liquefiable material in a solid state; providing the second object, which includes a surface portion that has a coupling structure with an undercut such that the second object can make a positive-fit connection with the first object; and pressing the second object against the first object with a tool that is in physical contact with a coupling-in structure of the second object while mechanical vibrations are coupled into the tool. The step of pressing and coupling vibrations into the tool continues until a flow portion of the thermoplastic material of the first object is liquefied and flows into the coupling structures of the second object. Thereafter, the thermoplastic material of the first object is permitted to re-solidify to yield a positive-fit connection between the first and second objects.