Composite Crash Box With Angled Ribs For Uniform Energy Absorption
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Solution Overview
Problem
Current crash absorber structures in vehicles, primarily made of steel, experience stepwise energy absorption during axial impacts, leading to uncontrolled failure and high repair costs, while alternative materials like fiber-reinforced plastics are expensive and prone to buckling, lacking a uniform rate of force absorption.
Innovation Solution
A structure with angled ribs, corrugated or zigzag-shaped ribs, and multiple layers with varying compressibility and failure properties, designed to absorb energy uniformly through controlled failure, providing robustness against both axial and transverse forces by redistributing force across interconnected ribs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel crash boxes are used, then high strength and reliability are achieved, but weight increases and fuel consumption rises
Solution Approach 1:
The patent employs fiber-reinforced plastic composite materials to manufacture crash boxes, combining polymer matrices with reinforcing fibers (glass, carbon, or natural fibers). This composite approach achieves strength comparable to steel while significantly reducing weight, directly resolving the contradiction between strength and weight.
2Strength
If transverse ribs are used for reinforcement, then structural strength is improved, but energy absorption becomes stepwise and uncontrolled
Solution Approach 1:
The patent introduces longitudinal ribs running axially along the crash box, adding a new dimensional element to the traditional transverse rib structure. This axial reinforcement creates continuous load paths that prevent stepwise failure, enabling controlled energy absorption while maintaining structural strength.
Solution Approach 2:
The patent employs corrugated or zigzag-shaped axial ribs instead of straight ribs. This curvature introduces progressive deformation zones that distribute energy absorption continuously along the axial direction, preventing sudden stepwise failure and achieving controlled failure modes.
3Ease of manufacture
If short-glassfiber-reinforced plastics are used, then cost is reduced, but buckling resistance decreases for long installed lengths
Solution Approach 1:
The patent segments the reinforcement function between short glass fibers dispersed in the polymer matrix and the structural geometry (axial ribs). The short fibers provide local reinforcement and crack bridging, while the axial ribs provide global structural stability, enabling long installed lengths without buckling while maintaining cost-effectiveness of short-fiber reinforcement.
Solution Approach 2:
The patent uses short-glassfiber-reinforced plastic composites with optimized fiber length, concentration, and orientation. Combined with the axial rib structure, this composite material system achieves sufficient buckling resistance for long installed lengths while maintaining the cost advantages of short-fiber processing over continuous fiber techniques.
4Use of energy by moving object
If continuous-fiber-reinforced components are used, then energy absorption capability is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent employs short-glassfiber-reinforced plastics instead of expensive continuous fiber composites. The short fibers provide sufficient reinforcement for crash box applications, and the material can be processed using cost-effective injection molding techniques, significantly reducing manufacturing cost while maintaining adequate energy absorption capability.
Solution Approach 2:
The patent optimizes the composite material formulation using short glass fibers at specific concentrations and lengths, combined with appropriate polymer matrices. This composite approach achieves the required energy absorption performance through the synergistic effect of fiber reinforcement and structural design, without incurring the high costs of continuous fiber processing.
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 structure achieves a uniform rate of force absorption and controlled failure, reducing repair costs and improving energy absorption efficiency, while being cost-effective and robust against non-ideal impact stresses.
Implementation Method 1
the structure has ribs for reinforcement, where the ribs have been arranged with respect to one another at an angle with respect to the axial direction in such a way that on failure of a rib a force acting on the structure is immediately absorbed axially by another rib
Implementation Method 2
the structure has ribs running axially, the ribs being in essence corrugated or of zigzag shape
Implementation Method 3
the structure comprises, in the direction of impact, at least two layers, each of which has different compressibility properties and different failure properties
Data Source
AI summary
A structure for absorbing energy from impacts thereon, the structure being plastically deformable by an impact, with, if appropriate, the possibility that it is at least to some extent disrupted. The structure can include a) ribs for reinforcement, the ribs arranged with respect to one another at an angle with respect to the axial direction such that on failure of a rib a force acting on the structure is immediately absorbed axially by another rib, b) ribs running axially, the ribs being in essence corrugated or of zigzag shape, c) at least one rib running axially in a first plane and connected to at least two ribs running axially in a second plane rotated with respect to the first plane. The structure includes, in the direction of impact, at least two layers, each of which has different compressibility properties and different failure properties.