Door Impact Beam Bead for Cross-Section Collapse Prevention

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Solution Overview

Problem

Existing door impact beams, particularly those with hat-shaped or U-shaped cross-sectional designs, face issues with cross-section collapse during collisions, leading to load loss and potential fracture, especially when made from high-tensile steel sheets with low elongation, which compromises their energy absorption performance.

Innovation Solution

A door impact beam with a molded body made of a thin steel sheet featuring a hat-shaped cross-sectional shape and a bead projecting outwardly in the longitudinal direction from the groove bottom portion to distribute deformation and prevent cross-section collapse, thereby enhancing energy absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a hat-shaped open cross-sectional shape is used to reduce size and weight, then the door impact beam can be disposed in a narrow space, but cross-section collapse occurs during collision leading to load loss

Engineering Contradiction:
Improvecross-section sizeVSAvoidcross-section stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by discontinuing the center portion of the groove bottom portion to create a specific local structure. This discontinuation prevents cross-section collapse during collision while maintaining the overall hat-shaped open cross-sectional geometry. The local modification allows the beam to absorb impact energy through controlled deformation without catastrophic failure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The groove bottom portion is segmented by discontinuing its center portion, creating distinct regions that can deform independently during impact. This segmentation prevents the entire cross-section from collapsing uniformly, allowing for progressive energy absorption while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

2Strength

If high-tensile steel sheet with small elongation is used to increase strength, then the door impact beam can withstand higher loads, but fracture occurs due to concentrated distortion

Engineering Contradiction:
Improveload bearing capacityVSAvoidfracture resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

By discontinuing the center portion of the groove bottom, the patent creates a local structure that promotes distributed deformation. This local modification prevents stress concentration in high-tensile steel sheets with small elongation, allowing the material to deform plastically without fracturing while maintaining high load-bearing capacity.

Inventive Principle:
Principle #3Local quality

3Reliability

If the groove bottom portion is discontinued to prevent collapse, then cross-section stability improves, but load loss occurs reducing energy absorption performance

Engineering Contradiction:
Improvecross-section stabilityVSAvoidcollision energy absorption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The discontinuation of the groove bottom center portion segments the structure to prevent catastrophic collapse while creating controlled deformation zones. These segmented regions absorb collision energy through progressive bending and deformation, converting impact energy into plastic work rather than allowing sudden structural failure that would result in energy loss.

Inventive Principle:
Principle #1Segmentation

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 solution effectively suppresses load loss and fracture by distributing impact stress, allowing for efficient collision energy absorption and improved performance even in high-tensile steel sheets, while maintaining a reduced size and weight.

Implementation Method 1

a bead 13 which projects in a shape having a curved surface toward the outside of the open cross-sectional shape is formed toward a longitudinal direction in a part of the groove bottom portion 4

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3162602B1Door impact beam
Publication Date: 2020.01.08 NIPPON STEEL CORPORATION
  • EP3162602B1 patent drawingFigure 1
  • EP3162602B1 patent drawingFigure 2(a)~2(d)
  • EP3162602B1 patent drawingFigure 3A

AI summary

A main body (2) has door attaching portions respectively formed on both end sides of a long longitudinal direction thereof and a bending deformation generation portion (3) disposed between the door attaching portions, and the bending deformation generation portion (3) has a groove bottom portion (4), two edge line portions (5a, 5b), two vertical wall portions (6a, 6b), two curved portions (7a, 7b), and two flanges (8a, 8b). There is provided a bead (13) which is formed toward the longitudinal direction of the main body (2) in a part of the groove bottom portion (4) in a manner to project in a shape having a curved surface toward the outside of a cross-sectional shape of the bending deformation generation portion (3) so as to oppose an impact load acting on a door impact beam (1).