Frangible Front Bumper Mount for Pedestrian Impact Mitigation

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Solution Overview

Problem

Existing vehicle bumper supports, particularly those with rigid elements, pose a risk of significant injury to pedestrians in frontal collisions by creating pressure points, and solutions like adding shock absorbers are costly and add weight to the vehicle.

Innovation Solution

A vehicle front bumper support with a first and second wall connected non-parallelly, featuring frangible lines that break under impact to reduce force transmission to pedestrians, maintaining rigidity without additional parts or weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid bumper support is used to maintain bumper skin shape and support accessories, then structural strength and stability are improved, but pedestrian protection deteriorates due to pressure points created during collision

Engineering Contradiction:
Improvestructural strengthVSAvoidpedestrian injury risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The bumper support is segmented into a first wall and a second wall connected at an angle, creating distinct functional zones. The first wall provides structural support while the second wall with frangible lines controls force transmission during pedestrian impact, separating the support function from the harmful rigid contact.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bumper support incorporates frangible lines with controlled mechanical properties that change the structural parameters during impact. These lines are designed to rupture at specific force thresholds, transforming the rigid structure into a controlled deformation system that reduces peak forces on pedestrians while maintaining normal rigidity during non-collision conditions.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a shock absorber is added behind the bumper skin to improve pedestrian protection, then pedestrian safety is improved, but vehicle cost and weight increase

Engineering Contradiction:
Improvepedestrian protectionVSAvoidvehicle weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The bumper support structure serves its own dual function: it provides structural support during normal operation and automatically activates pedestrian protection through its frangible lines during collision. The structure itself performs the energy absorption function that would otherwise require separate shock absorbers, eliminating the need for additional components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The support function and energy absorption function are merged into a single integrated bumper support structure. The frangible lines are incorporated directly into the support walls, combining the structural support role with the collision mitigation role, eliminating the need for separate shock absorbers and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If the second wall is made more rigid to support accessories and bumper skin, then structural stability is improved, but force transmission to pedestrians increases during impact

Engineering Contradiction:
Improvestructural stabilityVSAvoidforce transmission to pedestrian
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The second wall exhibits local quality variations through the incorporation of frangible lines at specific locations. These lines create zones of controlled weakness that allow force redistribution during impact, while the remaining portions of the wall maintain sufficient rigidity for structural support and accessory mounting.

Inventive Principle:
Principle #3Local quality

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 reduces pedestrian injury risk by controlled rupture of the bumper support, ensuring effective support of the bumper skin and accessories while avoiding added mass and cost.

Implementation Method 1

the second wall has a first frangible line extending in the same transverse direction as the junction between the first and second walls... in the event of a collision with a pedestrian, the bumper support will break at the first frangible line under the forces generated by the impact

Methodology Applied
Scientific EffectFracture Mechanics: Fracture Mechanics

Data Source

PatentEP4217239B1Bumper mount with programmed rupture
Publication Date: 2026.01.28 STELLANTIS AUTO SAS
  • EP4217239B1 patent drawingFigure 1~2
  • EP4217239B1 patent drawingFigure 3~4

AI summary

Front bumper mount (1) of a vehicle (100), comprising a first wall (11) connected to a second wall (12) not aligned with the first wall (11), the junction between said two walls (11, 12) extending in a transverse direction (Y) to the mount, the first wall (11) being intended to be arranged behind a bumper skin (101) of a vehicle (100), the second wall (12) to be extended under a hood nose (102) when the mount (1) is fitted to a vehicle (100), characterised in that the second wall (12) comprises a first frangible line (121) extending in the same transverse direction as the junction between the first (11) and the second wall (12).