Resin-Filled Crash Absorber Structure for Wet-Resistant Axial Crush
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Solution Overview
Problem
Existing automotive parts that absorb crashworthiness energy by buckling deformation in a bellows-shaped manner during axial crush have difficulty improving energy absorption properties and are prone to reduced performance in wet environments due to low water resistance.
Innovation Solution
An automotive crashworthiness energy absorptive part comprising a tubular member and a closed cross section space forming wall member filled with a rubber-modified epoxy resin, which adheres to the tubular member and maintains adhesion even in wet conditions, allowing repeated bellows-shaped deformation without reducing deformation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If foaming filler or foamed body is used to improve strength and rigidity, then bending strength and torsional stiffness are improved, but crashworthiness energy absorptive properties during axial crush cannot be improved
Solution Approach 1:
The patent changes the material parameters by selecting resin materials with specific tensile breaking elongation (2% or more and less than 80%) and specific mechanical properties (adhesive strength ≥12 MPa, compressive nominal stress ≥6 MPa at 10% strain). This parameter optimization allows the resin to accommodate axial crushing deformation while maintaining adhesion, enabling energy absorption without compromising structural strength.
Solution Approach 2:
The patent uses composite material structure by combining resin material with steel sheet components (tubular member and closed cross section space forming wall member). The resin-steel composite structure enables both strength enhancement and energy absorption capability, as the resin fills the closed cross section space and bonds to the steel components, creating a synergistic structure that achieves both bending strength and crashworthiness energy absorption.
2Strength
If conventional resin materials are used to fill closed cross section space, then strength is improved, but water resistance is low and performance degrades in wet environments
Solution Approach 1:
The patent changes the chemical and physical parameters of the resin material by specifying tensile breaking elongation of 2% or more and less than 80%, which indicates a balanced elasticity and strength profile. This parameter range selects resin materials that maintain their mechanical properties and adhesion in wet environments, ensuring water resistance and long-term performance stability while preserving strength enhancement.
3Strength
If resin with high adhesion is selected to maintain bond strength, then adhesive strength is improved, but deformation flexibility during axial crush is reduced
Solution Approach 1:
The patent optimizes the resin material parameters by selecting tensile breaking elongation in the range of 2% or more and less than 80%. This parameter range creates a balance where the resin maintains sufficient adhesion strength (≥12 MPa) to bond with steel components while having enough elasticity to deform during axial crushing without excessive stiffness that would restrict deformation flexibility.
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 part effectively absorbs crashworthiness energy by repeated bellows-shaped deformation while maintaining water resistance, ensuring stable energy absorption over time in various weather conditions.
Implementation Method 1
a resin provided in the closed cross section space, wherein the resin contains a rubber-modified epoxy resin and a hardener, and has a tensile breaking elongation of 2% or more and less than 80%, an adhesive strength with the tubular member and the closed cross section space forming wall member of 12 MPa or more
Data Source
AI summary
An automotive crashworthiness energy absorptive part absorbs crashworthiness energy by crushing axially when a crashworthiness load is input from a front side or a rear side of an automotive body, and includes: a tubular member formed of a steel sheet with a tensile strength of 590 MPa to 1180 MPa, the tubular member including a top portion and a pair of side wall portions continuous from both ends of the top portion via corner portions; a closed cross section space forming wall member formed of a steel sheet with a tensile strength lower than the tubular member, the closed cross section space forming wall member being disposed on an inner surface side of the tubular member and forming a closed cross section space between the closed cross section space forming wall member and at least the corner portion; and a resin provided in the closed cross section space.