Vehicle Bumper Beam Asymmetric Attachment Stiffness
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Solution Overview
Problem
Bumper beams with U-shaped cross sections tend to twist during non-vertical collisions, particularly when their attachment portions are narrow vertically and broad horizontally, compromising their crash performance as integrated crash boxes.
Innovation Solution
A bumper beam design featuring two attachment portions with a large web height that decreases towards the center, incorporating hat-shaped side flanges with upwardly bent ends and a central groove, reinforced by a hat-profile member that forms transverse bulkheads when welded, enhancing structural integrity and crash properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the attachment portions are made narrow in the vertical direction and broad in the horizontal direction to reduce size, then the bumper beam can be more compact, but the bumper beam tends to twist during non-vertical collisions
Solution Approach 1:
The attachment portions are designed with asymmetric dimensions where the web height (vertical dimension) is made larger than the flange width (horizontal dimension), reversing the conventional proportioning. This asymmetric geometry provides greater vertical stiffness to resist twisting during non-vertical collisions while maintaining a compact overall size.
Solution Approach 2:
The cross-sectional dimensions of the attachment portions are optimized locally with increased web height specifically at the attachment areas to enhance vertical stiffness where needed, while the central portion of the bumper beam maintains different dimensions for overall structural integrity. This localized quality enhancement addresses twisting resistance without unnecessarily increasing the overall size.
2Strength
If the web height of attachment portions is increased to prevent twisting, then collision resistance improves, but the bumper beam becomes broader and less compact
Solution Approach 1:
The larger web height is applied specifically and locally only to the attachment portions where collision forces are transmitted to the vehicle structure, rather than uniformly increasing the dimensions of the entire bumper beam. This localized reinforcement provides the necessary collision resistance while keeping the overall bumper beam compact.
Solution Approach 2:
The bumper beam is segmented into distinct functional zones: the attachment portions with large web height for collision resistance and the central hat-shaped portion with different dimensions for overall structural integrity. This segmentation allows each zone to be optimized for its specific function without compromising the other.
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 the crash performance of bumper beams by preventing twisting during collisions, eliminating the need for additional crash boxes and ensuring robust attachment to the vehicle.
Implementation Method 1
The side edges 38 are welded by means of weld beads 39, 40 to the webs 13, 14 of the bar
Data Source
Figure 1~6
Figure 3~5
AI summary
A bumper beam for a vehicle has two attachment portions (15, 16) with a U-shaped cross section open towards the vehicle. Each attachment portion has a reinforcing member (29) in the form of a hat-profile located within the attachment portion and across the latter, with its webs (31, 32) welded to the webs (13, 14) of the attachment portion. The side flanges (33, 34) of the hat profile have holes (35, 36) for bolts by means of which the side flanges and thereby the bumper beam can be attached to a structural part of the vehicle and the attachment section has holes (41) to allow fastening bolts of this kind to be fastened through these holes.