Frangible Hood Bumper Energy Absorption
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Solution Overview
Problem
Conventional hood bumpers are ineffective in managing impact energy during collisions, primarily transmitting force to pedestrians and causing severe injuries, as they lack energy absorption capabilities due to solid connections that do not absorb energy under direct impact.
Innovation Solution
A hood bumper design featuring a tower with spaced legs and a base with frangible transition pieces and an energy management protrusion that allows for energy absorption by fracturing under predetermined force, enabling the bumper to break away and manage impact energy without additional devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional solid connections are used in hood bumper assemblies, then structural strength is maintained, but energy absorption capability is lost
Solution Approach 1:
The hood bumper assembly is divided into multiple segments including a base, tower, and frangible transition pieces. These segments are connected through frangible areas that allow controlled separation during impact, enabling energy absorption while maintaining structural integrity during normal operation
Solution Approach 2:
The frangible transition pieces are designed with specific geometric parameters and material properties that allow them to fracture at predetermined forces. The transition pieces include frangible areas with reduced cross-sectional area or weakened bonds that change the force required to break them, enabling energy management through controlled failure
2Adaptability or versatility
If threaded connections are used for height adjustment, then adjustability is improved, but energy absorption during impact is reduced
Solution Approach 1:
The threaded connection is segmented into adjustable height components while the frangible transition pieces provide a separate energy absorption mechanism. This allows the threaded connection to perform its adjustment function without being required to absorb impact energy
Solution Approach 2:
The energy absorption function is extracted from the threaded connection and assigned to the frangible transition pieces. This separation of functions allows the threaded connection to focus on adjustability while the frangible pieces handle energy absorption through controlled fracture
3Loss of energy
If frangible areas are designed to fracture at predetermined force, then energy absorption is improved, but structural integrity is reduced
Solution Approach 1:
The frangible transition pieces have localized frangible areas with specific geometric features or material properties that make them susceptible to fracture at predetermined forces. These local weaknesses are strategically placed while the rest of the structure maintains full structural integrity
Solution Approach 2:
The frangible areas are pre-designed and pre-positioned in the transition pieces before impact occurs. The controlled fracture paths are established during manufacturing, allowing predictable energy absorption behavior when impact forces exceed the predetermined threshold
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 effectively absorbs and manages impact energy by fracturing transition pieces and engaging the energy management protrusion, reducing the force transmitted to pedestrians and enhancing vehicle safety during collisions.
Implementation Method 1
each transition piece includes a frangible area that is configured to fracture when a predetermined force is applied to the frangible area
Implementation Method 2
an energy management protrusion extending from the base floor, where the energy management protrusion extends toward the cavity between the tower legs
Data Source
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AI summary
A hood bumper device for an automotive vehicle hood is disclosed that can absorb energy from an impact to the hood. The hood bumper device can fracture under a first predetermined force and then continue to absorb additional energy as the descent of a portion of the device is slowed.