Bumper Beam Inner Plate Structure for Delayed Buckling

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Solution Overview

Problem

Existing bumper beams face challenges in achieving high energy absorption efficiency due to difficulties in suppressing buckling of upper and lower wall sections and limited improvement in energy absorption efficiency.

Innovation Solution

A bumper beam design comprising a first member with a plate section, wall sections, and flange sections, a second member that closes the gap between the flange sections, and an inner plate joined to the wall sections, which is disposed substantially in parallel with the second member. This configuration enhances the maximum permissible load and delays buckling, thereby increasing energy absorption efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the plate thickness of the bumper beam is reduced to achieve weight reduction, then the weight decreases, but the strength of the bumper beam deteriorates

Engineering Contradiction:
Improveweight of bumper beamVSAvoidstrength of bumper beam
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The bumper beam employs a composite structure combining a thin-walled box-shaped main body with strategically placed reinforcing members. The main body is formed by joining multiple press-formed parts (front end press-formed part, rear end press-formed part, and side press-formed parts) to create a box-shaped cross-section. Reinforcing members are positioned at specific locations (front lower, rear lower, and web sections) to compensate for the reduced thickness, achieving both weight reduction and maintained strength through this composite approach.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If a reinforcing member is disposed in the fore-and-aft direction to reduce weight, then weight reduction is achieved, but the ability to suppress buckling of upper and lower wall sections deteriorates

Engineering Contradiction:
Improveweight of bumper beamVSAvoidbuckling suppression capability
Core Design Contradiction:
Weight of moving objectVSStability of the object's composition

Solution Approach 1:

Rather than using a single continuous reinforcing member, the invention employs multiple discrete reinforcing members positioned at specific critical locations where buckling is most likely to occur. These include front and rear lower reinforcing members at the ends and web reinforcing members at intermediate positions. This localized reinforcement strategy provides targeted buckling suppression while minimizing weight, as each reinforcing member is placed only where structurally necessary.

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If the plate thickness is reduced to improve fuel economy, then fuel economy improves, but the energy absorption efficiency deteriorates

Engineering Contradiction:
Improvefuel economyVSAvoidenergy absorption efficiency
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The bumper beam is designed to undergo controlled dynamic deformation during impact. The thin-walled box-shaped structure is engineered to deform progressively through controlled buckling and crushing modes, maximizing energy absorption. The reinforcing members are strategically positioned to guide this deformation process, ensuring that the structure absorbs energy efficiently through controlled collapse rather than brittle failure, thereby maintaining high energy absorption efficiency despite reduced plate thickness.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3248845B1Bumper beam
Publication Date: 2025.04.16 NIPPON STEEL CORPORATION
  • EP3248845B1 patent drawingFigure 1
  • EP3248845B1 patent drawingFigure 2A~2B
  • EP3248845B1 patent drawingFigure 3A~3C

AI summary

A bumper beam (1) includes a first member (2), a second member (3), and an inner plate (4). The first member (2) includes a top plate section (5), two vertical wall sections (6), and two flange sections (7a, 7b). The two vertical wall sections (6) connect to both side sections (5a, 5b) of the top plate section (5), respectively. The two flange sections (7a, 7b) connect to the two vertical wall sections (6), respectively. The second member (3) is plate-shaped, is joined to the two flange sections (7a, 7b) of the first member (2), and closes the gap between the two flange sections (7a, 7b) at least. The inner plate (4) is joined to the two vertical wall sections (6) of the first member (2) and is disposed substantially in parallel with the second member (3) in a space formed by the first member (2) and the second member (3). Out of the first member (2) and the second member (3), the second member (3) is disposed facing the outside of a vehicle. Such a bumper beam has high energy absorption efficiency.