Folded Tubular Strut End for Higher Connection Stiffness
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Solution Overview
Problem
Conventional struts in automotive vehicles face challenges in achieving sufficient bending stiffness in the connection area, often requiring costly inserts or inefficient forming methods that do not effectively distribute kinetic forces.
Innovation Solution
A strut design featuring an elongated tubular beam with a folded and flattened connecting end portion, where diametrically opposite inward fold lines meet at the longitudinal centerline, creating four material layers, and cold-formed to increase width and thickness, enhancing stiffness without inserts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional struts use straight tubular structures with traditional forming, then manufacturing is simple and cost-effective, but bending stiffness in the connection area is insufficient
Solution Approach 1:
The end portion of the tubular structure is segmented into four distinct material layers through folding, where each layer contributes to the overall stiffness. The fold lines divide the circular cross-section into quadrants, creating a multi-layered structure that resists bending more effectively than a single-layer structure.
Solution Approach 2:
The connection area is extended in the transverse dimension by increasing the width to greater than one quarter of the external circumference. This dimensional change creates a broader connection surface that improves bending stiffness and load distribution without requiring additional components.
2Strength
If inserts are added to increase connection area stiffness, then bending stiffness improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The folding process merges multiple layers of the tubular structure's own material to create the stiffened connection area. Instead of adding separate insert components, the structure utilizes its own material folded into four layers, achieving the stiffening effect through self-integration.
Solution Approach 2:
The tubular structure serves its own stiffening needs through the folding process, where the material itself is reconfigured to provide the required connection area stiffness. The structure uses its own geometric transformation rather than requiring external reinforcement components.
3Strength
If the end portion is folded and flattened to create four material layers, then bending stiffness increases, but manufacturing complexity increases
Solution Approach 1:
The folding and flattening process is performed as a preliminary forming operation on the tubular structure before final assembly. By pre-configuring the end portion into four layers during the forming stage, the structure achieves the required stiffness characteristics before entering the assembly process.
Solution Approach 2:
The geometric parameters of the end portion are changed through controlled folding and flattening, transforming the circular cross-section into a multi-layered flat structure. This parameter change increases the moment of inertia and section modulus, thereby improving bending stiffness.
4Strength
If cold-forming is applied to increase end portion width beyond C/4, then bending stiffness improves, but manufacturing complexity increases
Solution Approach 1:
Cold-forming is applied locally to the end portion of the tubular structure to increase its width to greater than one quarter of the external circumference. This localized quality change concentrates the stiffness enhancement where it is most needed for connection purposes, rather than uniformly thickening the entire structure.
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 design significantly improves bending stiffness in the connection area, allowing for efficient distribution of kinetic forces and improved load-carrying capabilities, while maintaining cost-effectiveness and manufacturing efficiency.
Implementation Method 1
The end portion of the tubular structure may have been cold-formed prior to, or after, being folded and flattened
Implementation Method 2
The connecting end portion may be comprised of a folded and flattened end portion of the tubular structure, in which diametrically opposite inward fold lines meet
Data Source
AI summary
A strut including an elongated beam portion and a connecting end portion. The elongated beam portion is a tubular structure having an external circumference, the connecting end portion is integral with the elongated beam portion, has a folded and flattened end portion of the tubular structure, and where diametrically opposite inward fold lines meet between flattened parts the end portion of the tubular structure. The resulting connecting end portion includes four material layers and the connecting end portion has a width transverse to a longitudinal centerline of the connecting end portion.