Crush Can Mounting Bracket for Bumper Beam Stress Reduction
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Solution Overview
Problem
Conventional front bumper systems face issues with stress concentration at the crush can/bumper beam interface, leading to crack initiation and reduced energy absorption capacity, which compromises vehicle safety and performance during collisions.
Innovation Solution
A crush can/bumper beam mounting interface is designed with enhanced load distribution and stress concentration reduction, utilizing a mounting bracket with flanges and perpendicularly protruding bracket members that are welded to the crush can, allowing for better folding behavior and energy absorption by minimizing crack initiation sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional CNC tooling or punch tooling processes are used to form the front portion of the crush can, then a mounting interface is provided, but stress concentration and crack initiation occur due to structural compromise
Solution Approach 1:
The mounting interface is segmented into multiple discrete attachment points (first and second attachment features) distributed across the front portion of the crush can. This segmentation allows loads to be distributed across multiple locations rather than concentrated at a single point, reducing stress concentration while maintaining manufacturability through standard forming processes.
Solution Approach 2:
The front portion of the crush can is designed with locally optimized attachment features that have enhanced load-bearing characteristics. These attachment features incorporate localized geometric modifications (such as reinforced flanges or integrated mounting brackets) that concentrate material and strength precisely where needed for mounting, while the rest of the crush can maintains its optimized folding geometry for energy absorption.
2Loss of energy
If the crush can is designed for complete energy absorption, then maximum collision energy is absorbed, but the bumper beam may detach from the crush can causing runway intrusion
Solution Approach 1:
The crush can is pre-designed with predetermined folding lines and hinge regions that guide the deformation pattern during collision. These preliminary structural features ensure that the crush can folds in a controlled manner along predetermined paths, maintaining attachment integrity with the bumper beam while systematically absorbing collision energy through progressive deformation rather than uncontrolled collapse.
Solution Approach 2:
The mounting interface incorporates built-in compliance and load distribution features that cushion the transition of loads from the bumper beam to the crush can. This preliminary cushioning mechanism prevents sudden load spikes that could cause detachment, allowing the system to absorb energy progressively while maintaining structural connection throughout the collision event.
3Ease of manufacture
If CNC or punch tooling processes are used to create the mounting interface, then the interface is formed, but weak points are created leading to stress concentration during loading
Solution Approach 1:
The mounting interface design incorporates geometric parameter optimizations that mitigate stress concentration. This includes using larger radius fillets at attachment features, optimizing the thickness distribution in mounted regions, and designing attachment flanges with gradual thickness transitions. These parameter changes allow the interface to be formed through conventional tooling while significantly reducing stress concentration factors during subsequent loading.
4Strength
If the bumper beam is rigidly attached to the crush can, then structural strength is improved, but energy absorption capacity is reduced due to restricted folding behavior
Solution Approach 1:
The mounting interface is designed to transition from a rigid connection state during normal operation to a controlled deformation state during collision. The attachment features incorporate elements that remain rigid under static and dynamic service loads but are designed to progressively deform or yield under extreme collision loads, allowing the crush can to fold and absorb energy while maintaining attachment integrity throughout the event.
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 maintains structural integrity by reducing stress concentration points, thereby improving vehicle safety and performance during collisions while maintaining weight and cost neutrality.
Implementation Method 1
The mounting bracket is welded to a front edge of the front portion of the box structure
Data Source
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AI summary
A bumper assembly for a vehicle, the bumper assembly including: a side rail; a bumper beam assembly coupled to the side rail; and a crush can assembly adapted to couple the bumper beam assembly to the side rail, the crush can assembly including: a box structure including a front portion and a rear portion, wherein the rear portion of the box structure is adapted to be coupled to the side rail; and a mounting bracket coupled to the front portion of the box structure, wherein the mounting bracket is adapted to be coupled to the bumper beam assembly. The mounting bracket includes a planar structure that is coupled to the front portion of the box structure and one or more bracket members that protrude substantially perpendicularly from the planar structure, wherein each of the one or more bracket members is adapted to be coupled to the bumper beam assembly.