Vehicle Bumper Crossmember Geometry for Offset Crash Load Redirection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bumper arrangements for motor vehicles do not effectively distribute impact forces during crashes, leading to peak loads and inadequate protection in offset collisions, as they lack optimal design features to engage and redirect impacting objects away from the passenger compartment.
Innovation Solution
A bumper arrangement featuring a hollow crossmember with obliquely downwardly oriented end portions, crash boxes strategically placed between the central and end regions, and a top-hat profile design that engages the wheel and wheel suspension to redirect impact forces, providing additional load paths and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the crossmember is designed with a conventional horizontal profile, then the structural simplicity is maintained, but the impact forces are not effectively distributed during crashes leading to peak loads
Solution Approach 1:
The crossmember is designed with asymmetric end portions that slope obliquely downwards at angles between 10-30 degrees relative to the longitudinal axis. This asymmetric geometry creates favorable force distribution during crashes by directing impact forces away from the passenger compartment while maintaining structural integrity. The oblique orientation of end portions optimizes the load path without requiring complex additional components.
Solution Approach 2:
The crossmember profile extends into the vertical dimension with end portions sloping downwards, creating a three-dimensional load distribution system. This vertical component adds another dimension to force management, allowing impact energies to be distributed through both horizontal and vertical load paths, thereby reducing peak loads on the passenger compartment.
2Reliability
If the end portions are designed to slope obliquely downwards, then impact forces are redirected away from the passenger compartment, but the manufacturing complexity increases
Solution Approach 1:
The slope angle of the end portions is optimized within a specific range of 10-30 degrees relative to the longitudinal axis. This parameter optimization ensures effective force redirection while maintaining manufacturability. The defined angle range balances crash protection performance with manufacturing feasibility, allowing standard fabrication processes to produce the oblique geometry efficiently.
3Strength
If the crossmember end portions are positioned to engage the wheel, then additional load paths are created for crash energy absorption, but the design complexity increases
Solution Approach 1:
The crossmember's oblique end portions automatically engage with the wheel structure during crashes, utilizing the existing wheel and suspension system as integral parts of the crash energy management system. This self-service approach creates additional load paths without requiring separate energy-absorbing components, as the wheel-suspension assembly naturally participates in absorbing and distributing crash forces.
Solution Approach 2:
The wheel and suspension system serves dual functions: normal vehicle operation and crash energy absorption. The oblique crossmember end portions are designed to engage this existing multi-functional system, allowing the wheel-suspension assembly to contribute to crash protection while maintaining its primary vehicle function, thereby avoiding additional dedicated components.
4Weight of moving object
If the hollow profile depth is reduced in the end portion by maximum 30%, then the weight is reduced and crash behavior is improved, but the structural strength may be compromised
Solution Approach 1:
The hollow profile depth is locally optimized along the crossmember length, with end portions having reduced depth (up to 30% less than the central portion) and the central portion maintaining full depth for maximum strength. This local quality variation allows weight reduction in less critical end regions while preserving structural integrity in the central load-bearing area, achieving optimal strength-to-weight ratio.
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 ensures even distribution of impact forces, preventing intrusion into the passenger compartment by redirecting impacts laterally and providing enhanced crash energy absorption and protection through engagement with the wheel and wheel suspension, thereby improving crash behavior and reducing peak loads.
Implementation Method 1
the crash boxes hold, for example, in the manner of a concertina and thus convert crash energy into deformation work
Data Source
AI summary
A bumper arrangement for a motor vehicle, having a crossmember which is able to be coupled to a motor vehicle by means of crash boxes. The crossmember is designed as a hollow profile which is open on one side. An opening of the hollow profile faces forwards. The crossmember is designed in its end portions to run with an orientation obliquely downwards with respect to the vertical direction.