Crash Box With Alternating Porous Metal Layers
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Solution Overview
Problem
The existing crash box designs, which apply heat to form a soft part for deformation, face issues with thermal conduction leading to an indefinite boundary and reduced ability to absorb impact energy reliably due to less effective bellows shape deformation.
Innovation Solution
A crash box design featuring alternately formed metal layers with varying bubble volumes, where a bulk layer and a porous layer with a higher bubble content are stacked axially, and manufactured using a 3D forming process with controlled laser irradiation to create distinct deformation properties, allowing for efficient impact energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat is applied to a part of the crash box to form a soft part, then the soft part serves as a starting point for bellows-shape deformation, but thermal conduction causes the boundary between the soft part and surrounding parts to become indefinite, reducing deformation effectiveness
Solution Approach 1:
The crash box is divided into multiple layers with different bubble volume ratios (first layer: 30-70% bubbles, second layer: 70-95% bubbles), creating distinct segments with different deformation characteristics. This segmentation allows clear boundary definition between soft and hard parts without thermal conduction issues, enabling reliable bellows-shape deformation initiation at specific locations.
Solution Approach 2:
The invention uses composite structure with alternating layers of metal foam having different porosity (bubble volume ratios). The first layer (lower porosity) and second layer (higher porosity) are bonded together to form a composite material structure that combines different mechanical properties, allowing controlled deformation while maintaining clear boundaries between regions.
2Ease of operation
If a soft part is formed by heat treatment, then deformation can start at that part, but the thermal conduction to surrounding parts makes the boundary indefinite and reduces bellows shape deformation effectiveness
Solution Approach 1:
The crash box is divided into multiple layers with different bubble volume ratios (first layer: 30-70% bubbles, second layer: 70-95% bubbles), creating distinct segments with different deformation characteristics. This segmentation allows clear boundary definition between soft and hard parts without thermal conduction issues, enabling reliable bellows-shape deformation initiation at specific locations.
Solution Approach 2:
The invention changes the physical parameter of bubble volume ratio to create different deformation characteristics in different layers. By controlling the bubble volume ratio (30-70% for first layer, 70-95% for second layer), the material transitions from harder to softer regions, enabling controlled deformation initiation without thermal treatment and maintaining sharp boundaries.
3Ease of manufacture
If uniform metal structure is used throughout the crash box, then manufacturing is simpler, but the ability to control deformation into bellows shape and absorb impact energy is reduced
Solution Approach 1:
The invention uses composite structure with alternating layers of metal foam having different porosity (bubble volume ratios). The first layer (lower porosity) and second layer (higher porosity) are bonded together to form a composite material structure that combines different mechanical properties, allowing controlled deformation while maintaining clear boundaries between regions.
Solution Approach 2:
Different regions of the crash box are given different local qualities through varying bubble volume ratios. The first layer has 30-70% bubbles while the second layer has 70-95% bubbles, creating local variations in material properties that enable controlled deformation behavior and reliable impact energy absorption at specific locations.
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 enables reliable deformation into a bellows shape and enhanced impact energy absorption, reducing the risk of damage and improving energy absorption efficiency compared to traditional methods.
Implementation Method 1
a first step of forming a first layer by irradiating a metal powder with a laser and thereby curing the metal powder
Implementation Method 2
forming a first layer by irradiating a metal powder with a laser and thereby curing the metal powder
Implementation Method 3
a second step of forming a second layer by irradiating a metal powder with a laser and thereby curing the metal powder by using a smaller amount of heat-input energy for the laser than that used in the first step
Data Source
AI summary
A crash box capable of easily deforming into a bellows shape and absorbing impact energy more reliably, and its manufacturing method are provided. The present disclosure is applied to a crash box which is partly deformed in an axial direction to absorb impact energy when the crash box receives an impact in the axial direction. A first layer made of metal and a second layer made of metal containing a larger volume of bubbles than that of the first layer are alternately formed in the axial direction in the crash box according to the present disclosure.