Bumper Beam Compressibility via Localized Fiber Orientation

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Solution Overview

Problem

Existing bumper beams for motor vehicles face limitations in maximizing shock absorption travel due to geometric constraints and component bulk, particularly in the longitudinal direction, which restricts the absorption stroke and increases stress concentration during impacts.

Innovation Solution

A bumper beam with a W-shaped profile and unidirectional fibers in horizontal sides and bidirectional or multiaxial reinforcements in vertical sides, where the fibers are sandwiched between plies of bidirectional reinforcement, enhances compressibility and resistance, allowing for increased absorption stroke by facilitating breakage of horizontal flanks under perpendicular forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the beam is made more compressible to increase absorption stroke, then the absorption stroke is improved, but the structural strength and resistance to deformation deteriorate

Engineering Contradiction:
Improveabsorption strokeVSAvoidstructural strength
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The beam structure applies local quality by differentiating the properties of horizontal and vertical flanks. Horizontal flanks use unidirectional fibers optimized for compressibility and controlled breakage to increase absorption stroke, while vertical flanks use bidirectional or multiaxial reinforcements optimized for strength and resistance to deformation. This localized differentiation allows each part to perform its specific function optimally without compromising overall structural integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The beam employs composite materials with different fiber orientations in different regions. Unidirectional fibers are used in horizontal flanks to facilitate compressibility and breakage, while bidirectional or multiaxial reinforcements are used in vertical flanks to maintain structural strength. This composite approach allows the beam to simultaneously achieve both compressibility for increased absorption stroke and sufficient strength to resist deformation.

Inventive Principle:
Principle #40Composite materials

2Length of moving object

If geometric constraints and component bulk are reduced to maximize absorption travel, then the absorption stroke is improved, but the structural integrity and ability to withstand impact forces deteriorate

Engineering Contradiction:
Improveabsorption travelVSAvoidimpact resistance
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The solution applies local quality by making the horizontal flanks more compliant and breakable to increase absorption travel, while keeping the vertical flanks strong and rigid to maintain impact resistance. The unidirectional fibers in horizontal flanks allow controlled breakage that increases absorption distance, while bidirectional reinforcements in vertical flanks prevent catastrophic failure under impact loads.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The beam is segmented into horizontal and vertical flanks with different structural properties. This segmentation allows the horizontal flanks to be optimized for compressibility and breakage (increasing absorption travel) while vertical flanks are optimized for strength (maintaining impact resistance). The support member is also segmented into multiple blades to distribute and apply reaction forces effectively.

Inventive Principle:
Principle #1Segmentation

3Strength

If the horizontal flanks are made more resistant to breakage, then the structural integrity is improved, but the absorption stroke is reduced

Engineering Contradiction:
Improvestructural integrityVSAvoidabsorption stroke
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The invention applies local quality by using unidirectional fibers in horizontal flanks that are specifically oriented to facilitate breakage under compressive loads. This local design choice in horizontal flanks contrasts with the bidirectional reinforcements in vertical flanks, allowing the horizontal flanks to break and increase absorption stroke while the vertical flanks maintain structural integrity.

Inventive Principle:
Principle #3Local quality

4Length of moving object

If the vertical sides are made weaker to facilitate horizontal flank breakage, then the absorption stroke is improved, but the ability to withstand and transmit reaction forces deteriorates

Engineering Contradiction:
Improveabsorption strokeVSAvoidreaction force resistance
Core Design Contradiction:
Length of moving objectVSForce

Solution Approach 1:

The solution applies local quality by using bidirectional or multiaxial reinforcements specifically in vertical sides, making them stronger than horizontal flanks. This localized strengthening allows vertical sides to withstand and transmit reaction forces effectively while horizontal flanks break to increase absorption stroke. The support member blades are positioned to apply forces that promote horizontal flank breakage while vertical flanks resist deformation.

Inventive Principle:
Principle #3Local quality

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 increases the absorption stroke of the bumper beam, reducing the force transmitted to the chassis and passenger compartment during impacts, thereby minimizing deformation and enhancing safety by dissipating mechanical energy more effectively.

Implementation Method 1

By providing the horizontal flanks with such fibers, their breakage is facilitated during the absorption of a shock since they are subjected to forces whose direction is perpendicular to the axis of the fibers.

Methodology Applied
Scientific EffectFracture Mechanics: Fracture Mechanics

Implementation Method 2

the beam comprises bidirectional or multiaxial reinforcements in at least some of its vertical sides, the bidirectional or multiaxial reinforcements being chosen from a list comprising: tape, fabric, nonwoven, mat

Methodology Applied
Scientific EffectComposite Materials: Composite Materials

Implementation Method 3

the beam has a W-shaped profile so that it comprises four horizontal sides and three vertical sides

Methodology Applied
Scientific EffectForce distribution:

Data Source

PatentEP3086984B1Increase of the compressibility of a bumper beam
Publication Date: 2019.04.17 COMPAGNIE PLASTIC OMNIUM SA
  • EP3086984B1 patent drawingFigure 1~2
  • EP3086984B1 patent drawingFigure 3~4
  • EP3086984B1 patent drawingFigure 5~6

AI summary

The invention relates to the bumper beam (2) of a motor vehicle comprising a chassis and including at least one horizontal flank (4) and at least one vertical flank (6) extending longitudinally to the beam, which includes at least one bearing member (10) arranged such as to be supported on the chassis and to exert a reaction force in one direction on said at least one horizontal flank during the absorption of an impact by said beam, said bearing member being stronger than said at least one horizontal flank in the direction of the reaction force.