Variable Stiffness Belly Pan for Pedestrian Protection and Damage Control
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Solution Overview
Problem
Existing motor vehicle designs face challenges in balancing energy absorption and dissipation in low-speed frontal collisions, particularly in minimizing damage while ensuring pedestrian safety by achieving a delicate balance in front fascia stiffness.
Innovation Solution
A belly pan with a body and integrated stiffeners having distinct peak section forces in different zones (forwardmost, intermediate, and rearwardmost) is designed, where the stiffness increases gradually, allowing for controlled energy absorption and dissipation, using materials like polypropylene or steel, to minimize damage and enhance pedestrian safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the front fascia is made soft to reduce pedestrian injury risk, then pedestrian safety is improved, but vehicle damage in low-speed collisions increases
Solution Approach 1:
The belly pan is designed with spatially varying stiffness characteristics, featuring a forwardmost zone with lower stiffness (peak section force F1 of 3-5 kN) for pedestrian safety, and rearward zones with progressively higher stiffness (F2 of 10.5-12.5 kN, F3 of 15-17 kN) for damage resistance. This local differentiation allows the same component to serve both protective functions.
Solution Approach 2:
The belly pan is divided into three distinct zones along its length, each with tailored stiffness properties. The forwardmost zone, intermediate zone, and rearwardmost zone are segmented to progressively manage energy absorption, allowing the structure to deform controllably in different regions during impact while maintaining overall structural integrity.
2Strength
If the front fascia is made stiff to minimize vehicle damage, then vehicle damage resistance is improved, but pedestrian safety deteriorates
Solution Approach 1:
The belly pan implements local quality by positioning stiffer materials and thicker sections in the rearward zones (F2: 10.5-12.5 kN, F3: 15-17 kN) where structural support is needed, while maintaining softer characteristics in the forwardmost zone (F1: 3-5 kN) that directly contacts pedestrians during impact.
Solution Approach 2:
The stiffness parameters of the belly pan are precisely controlled through variation in material properties and geometric dimensions across different zones. The peak section forces are tuned to specific ranges (F1: 3-5 kN, F2: 10.5-12.5 kN, F3: 15-17 kN) to achieve the desired balance between pedestrian protection and damage resistance.
3Ease of manufacture
If the belly pan uses uniform stiffness throughout, then manufacturing is simplified, but energy absorption control deteriorates
Solution Approach 1:
Rather than using uniform stiffness, the belly pan employs local quality with three distinct stiffness zones. This approach maintains manufacturing feasibility through integrated molding while achieving superior energy absorption control through spatially differentiated mechanical properties.
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 belly pan effectively manages energy absorption and dissipation, reducing pedestrian injury risks and minimizing vehicle damage and repair costs by providing a controlled crushable structure that absorbs impact energy while maintaining structural integrity.
Implementation Method 1
there is a fundamental challenge of managing energy absorption and dissipation
Implementation Method 2
there is a fundamental challenge of managing energy absorption and dissipation
Implementation Method 3
the belly pan has a body including a stiffener having a forwardmost zone with a peak section force F1, an intermediate zone with a peak section force F2 and a rearwardmost zone with a peak section force F3 wherein F1<F2<F3
Data Source
AI summary
A belly pan is provided for a motor vehicle. The belly pan includes a body having at least one stiffener with a forwardmost zone of peak section force F1, an intermediate zone of peak section force F2 and a rearwardmost zone of peak section force F3 where F1<F2<F3. Advantageously, the belly pan functions to provide pedestrian protection while simultaneously limiting vehicle damage resulting from a low-speed collision.