Motor Vehicle Crash Box Bead Orientation for Energy Absorption

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Solution Overview

Problem

Existing crash boxes for motor vehicles face inefficiencies in energy absorption and deformation prediction during impacts, leading to fluctuating forces and suboptimal design, particularly due to material accumulation and interference issues with traditional bead configurations.

Innovation Solution

The crash box design features beads that vary in orientation between projecting and retracting along the edge, facilitating an accordion-like deformation and allowing for more precise energy absorption, enabling longer beads that span the entire width of the deforming body, thus guiding plastic deformation and regulating energy absorption more accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If traditional bead configurations are used in crash boxes, then energy absorption capacity is improved, but material accumulation and interference occur during crushing leading to fluctuating forces and reduced design predictability

Engineering Contradiction:
Improveenergy absorption capacityVSAvoiddeformation predictability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The bead configuration is designed to dynamically change orientation during crushing - transitioning from projecting to retracting at the edge. This dynamic adaptation allows the bead to guide deformation smoothly without causing material accumulation or interference, maintaining predictable deformation patterns while preserving energy absorption capacity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bead's geometric parameters are specifically optimized - its length spans the entire width of the deforming body, and its orientation varies continuously from projecting to retracting. These parameter changes enable the bead to regulate energy absorption more precisely while avoiding the harmful effects of material accumulation that plague traditional fixed-orientation beads.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If beads of greater length are used to guide plastic deformation more precisely, then energy absorption regulation is improved, but material accumulation and interference occur at the edges with traditional configurations

Engineering Contradiction:
Improvedeformation guidance precisionVSAvoidmaterial accumulation and interference
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The bead's orientation is designed to be dynamic rather than static - it transitions from projecting to retracting as crushing progresses. This dynamic behavior allows long beads to guide deformation precisely along their entire length without causing material accumulation at the edges, resolving the contradiction between deformation guidance precision and harmful material interference.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the bead remains projecting or retracted throughout crushing, then structural simplicity is maintained, but material accumulation and interference occur reducing crash box efficiency

Engineering Contradiction:
Improvebead configuration simplicityVSAvoidcrash box efficiency
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

Rather than maintaining a simple fixed orientation, the bead is designed to dynamically change its orientation from projecting to retracting during crushing. This dynamic complexity is necessary to prevent material accumulation and interference, thereby maintaining high crash box efficiency throughout the deformation process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bead's orientation parameter changes continuously during crushing - transitioning from projecting to retracting. This parameter change is essential to eliminate material accumulation and interference, preserving energy absorption efficiency despite the increased configurational complexity.

Inventive Principle:
Principle #35Parameter changes

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

This design results in a more constant and efficient force absorption during impacts, allowing for improved prediction and optimization of deformation patterns, enhancing the overall efficiency and accuracy of the crash box's energy management.

Implementation Method 1

which bead is shaped such as to guide the plastic deformation of the deforming body and to regulate the amount of energy required in order to produce a certain degree of deformation of the deforming body

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

the kinetic energy at the moment of impact is converted into deformation energy of the crash box in order to safeguard the integrity of the vehicle structure

Methodology Applied
Scientific EffectEnergy conversion through deformation: Deformation

Data Source

PatentEP2688771B1Bumper for motor vehicle
Publication Date: 2016.03.16 IMPERO PASQUALE
  • EP2688771B1 patent drawingFigure 1~2
  • EP2688771B1 patent drawingFigure 3A~4B
  • EP2688771B1 patent drawingFigure 3C~4D

AI summary

A shock absorber for motor vehicles, comprising: a deforming body (2) comprising a first portion (3) and a second portion (4) which are fixed to one another such as to identify a tubular member (5) which has a first axis and comprises a first wall (6) and a second wall (7) adjacent to one another, which intersect to identify an edge (8), each portion (3, 4) comprising a half-shell (9) and two fixing tabs (10) arranged respectively at opposite ends of the half-shell (9), at least a portion (3, 4) comprising at least a bead (11, 12) which develops along a perpendicular development with respect to the first axis. The bead (11, 12) develops continuously at least along a part of the first wall (6) and at least along a part of the second wall (7) of the tubular member (5), following at least the edge (8) identified between the first wall (6) and the second wall (7), the bead (11, 12), when it follows the first wall (6), being orientated projecting with respect to the zone of the external surface of the first wall (6) which surrounds the bead (11, 12), the bead (11, 12), when following the second wall (7), being orientated retracted with respect to the zone of the external surface of the second wall (7) which surrounds the bead (11, 12), the bead (11, 12), at the edge (8), varying orientation thereof between projecting and retracted.