Bow-formed Bumper Beam with Variable Web Height
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Solution Overview
Problem
Conventional bumper beams are either too rigid to absorb energy effectively in crashes against barriers or too weak to withstand impacts from thin poles, leading to localized collapse and buckling, especially when hit close to the vehicle's center.
Innovation Solution
A bow-formed bumper beam with a reduced web height towards the center, an open hat profile, and bent side flanges that can be fastened directly to vehicle supporting elements, made from high-strength steel or aluminum, featuring an elongate depression to enhance strength against local buckling while allowing for deformation in crashes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the bumper beam is made strong and stiff to withstand thin pole impacts, then it resists localized collapse and buckling, but it delays collapse in barrier crashes and fails to absorb energy effectively
Solution Approach 1:
The bumper beam features variable web height along its length, with the central portion having a reduced web height compared to the end portions. This creates different structural characteristics in different regions: the end portions maintain high strength for pole impacts, while the central portion allows controlled deformation for barrier crashes, enabling the beam to absorb energy effectively in both scenarios.
2Loss of energy
If the web height is reduced towards the center to improve energy absorption, then the beam yields better in barrier crashes, but it becomes weaker and more prone to local buckling
Solution Approach 1:
The web height parameter is varied along the length of the bumper beam, creating a gradient structure where the central portion has reduced height (allowing deformation) while the end portions maintain full height (providing strength). This parameter change enables the beam to exhibit different mechanical behaviors in different regions, balancing energy absorption with buckling resistance.
3Strength
If the bumper beam has a uniform strong structure, then it withstands thin pole impacts, but it creates high moment at midspan and buckles when hit close to the vehicle center
Solution Approach 1:
The bumper beam features variable web height along its length, with the central portion having a reduced web height compared to the end portions. This creates different structural characteristics in different regions: the end portions maintain high strength for pole impacts, while the central portion allows controlled deformation for barrier crashes, enabling the beam to absorb energy effectively in both scenarios.
Data Source
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AI summary
A bow-formed bumper beam for a vehicle has a hat profile with a central flange (11), two webs (12,13), and side flanges (14,15). The beam has fastening portions (20,21) at its sides where the side flanges form fastening areas (30-33) for fastening the beam to the vehicle with the central flange facing outwards. The profile height of the beam decreases continuously from the fastening portions towards the centre so that the profile height is less than two third of the highest profile height at the fastening portions. The central flange is wider at its centre than at its fastening portions and has a stiffener in the form of an elongate depression (16) that extends from the centre of the beam towards the fastening portions. In the area between the fastening portions, the side flanges have bent edges (26,27) and in association with the beginning of the bent edges, the side flanges have transverse dents.