Extruded Bumper Cross Member With Separated Flanges for Impact Stiffness
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Solution Overview
Problem
Existing bumper cross members for motor vehicles lack efficient stress absorption and structural enhancement while maintaining a low weight, and their production methods are often costly and require additional manufacturing steps.
Innovation Solution
A bumper cross member produced from an extruded hollow profile with separated flanges in the central zone, where the flanges are bent towards the impact side, increasing their distance from the rear wall and forming an arch shape, enhancing stress absorption and structural stiffness without additional weight, and produced through a single-piece extrusion process with cost-efficient methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If flanges are directly connected to the walls along their entire length, then the structural integrity is maintained, but the stress absorption capability and section modulus are reduced
Solution Approach 1:
The flanges are segmented from the side walls through separation cuts in the central zone, creating a partially separated structure. This segmentation allows the flanges to be positioned at a distance from the rear wall in the central zone while remaining connected at the end zones, thereby increasing the section modulus and stress absorption capability without completely compromising structural integrity.
Solution Approach 2:
The flanges are bent towards the impact side, creating an arch shape that increases the distance between the flanges and the rear wall in the central zone. This dimensional change in the longitudinal direction enhances the section modulus against bending while maintaining connection at the end zones.
2Strength
If additional manufacturing steps are used to enhance structural features, then the structural integrity and stress absorption are improved, but the production cost and complexity increase
Solution Approach 1:
The separation cuts and flange bending operations are integrated into the single-piece extrusion process. The hollow profile is extruded with pre-formed flanges, and the separation cuts are made during or after extrusion without requiring separate assembly steps or welding operations, thereby reducing production cost and complexity while achieving the enhanced structural features.
Solution Approach 2:
The extrusion process itself creates the flanges and separation structures in a single operation. The hollow profile is formed with the flanges already positioned and shaped, eliminating the need for additional manufacturing steps to add these structural features.
3Strength
If the flanges are separated completely from the rear wall, then the section modulus and stress absorption are maximized, but the structural integrity and weight increase
Solution Approach 1:
The flanges are partially separated from the side walls through separation cuts that extend only through the thickness of the wall, not completely detaching the flanges. This partial segmentation creates the arch shape and increases the section modulus while maintaining connection at the end zones, avoiding the need for additional material and weight increase.
Data Source
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AI summary
A bumper cross member for a motor vehicle is produced from an extruded hollow profile and has a front side forming an impact side, a rear side in opposition to the front side, end zones configured for connection to the motor vehicle, a central zone extending between the end zones and bent toward the impact side, and top and bottom sides connecting the rear side with the front side. Each of the top and bottom sides has a projecting flange which is separated from the rear side by a separation cut configured to end shy of the end zones so that the flanges are connected with the bumper cross member in the end zones.