Bumper Beam Transverse Dents for Cracking Reduction
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Solution Overview
Problem
Bumper beams with a hat profile often suffer from energy absorption inefficiencies and a high risk of cracking during collisions due to stress concentrations at the bent edges, particularly at fastening areas where the side flanges lack bent edges.
Innovation Solution
Incorporating transverse dents at the beginning of the bent edges on the side flanges of the bumper beam, which can flatten upon impact, reducing local tension and minimizing the risk of cracking, while maintaining the structural integrity and deformation properties through an open hat profile design with a central flange, webs, and side flanges made from high-strength steel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the side flanges have bent edges along a major part of their length to increase stiffness and deformation properties, then the beam becomes stiffer with better deformation properties, but stress concentrations occur at the bent edges particularly at fastening areas where cracking risk increases
Solution Approach 1:
The patent applies preliminary action by pre-forming transverse dents at the beginning of the bent edges before the collision occurs. These dents are strategically positioned to preemptively address the stress concentration issue. During impact, the dents flatten out first, absorbing and redistributing the stress before it can concentrate at the bent edges, thereby preventing cracking while maintaining the stiffness benefits of the bent edges.
Solution Approach 2:
The patent applies local quality by creating localized transverse dents only at specific critical locations (the beginning of bent edges near fastening portions) rather than modifying the entire side flange structure. This localized modification allows the bent edges to maintain their stiffness-enhancing function while the dents provide localized stress relief exactly where cracking is most likely to occur.
2Use of energy by moving object
If the side flanges have bent edges to improve energy absorption, then the deformation properties are enhanced, but the local tension in sensitive areas increases leading to potential structural failure
Solution Approach 1:
The patent converts the harmful stress concentration effect into a beneficial energy absorption mechanism. The transverse dents are designed to flatten out during collision, transforming the potentially harmful localized tension into a controlled deformation process that absorbs energy. The dents act as sacrificial features that yield in a controlled manner, converting the stress concentration problem into an energy absorption advantage.
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 solution enhances energy absorption and reduces the risk of cracking by distributing stress and allowing for controlled deformation, achieving a balance between structural strength and crash resistance.
Implementation Method 1
These dents can easily flatten out when the beam is bent in a collision so that the local tension in these sensitive areas of the side flanges is reduced
Data Source
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. In the area between the fastening areas, the side flanges have bent edges (26, 27) and in association with the beginning of the bent edges, they have transverse dents (29). These dents will easily be flattened out when the beam is bent in a collision so that the local tension in these sensitive areas is reduced. Thereby, the risk of cracking is reduced.