Crash Energy Absorber Structure for Repeated Bellows Buckling
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Solution Overview
Problem
Existing techniques fail to effectively improve collision energy absorption performance for automotive parts that undergo buckling deformation in the form of bellows when subjected to crashworthiness loads, such as those found in front side members or crash boxes, despite filling with foamed fillers or foam.
Innovation Solution
A crashworthiness energy absorption part comprising a tubular member made of high-strength steel sheet with a closed cross-section space filled with a rubber-modified epoxy resin and curing agent, which provides high adhesive strength and compression nominal stress, allowing for repeated buckling deformation without reducing deformation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If foamed filler or foam is filled in the interior of the automotive part, then the strength against bending deformation and collision energy absorption performance for bending deformation is improved, but the collision energy absorption performance for axis crush deformation in the form of bellows is not improved
Solution Approach 1:
The patent changes the physical and chemical parameters of the filling material from conventional foamed resin to a specific viscous resin composition with controlled viscosity (100-10000 Pa·s), tensile breaking elongation (80% or more), and adhesive strength (12 MPa or higher). This parameter optimization enables the resin to effectively transmit compressive forces while allowing the tubular member to undergo repeated bellows deformation, thereby improving collision energy absorption performance for axis crush deformation.
Solution Approach 2:
The patent uses a composite material system consisting of a tubular member made from high-strength steel sheet (590-1180 MPa grade) filled with a specially formulated viscous resin. The combination of the steel tubular structure and the engineered resin creates a composite system that simultaneously provides bending strength and enables effective energy absorption during axial compression through bellows deformation.
2Strength
If the interior of the automotive part is filled with foamed filler or foam, then the stiffness against torsional deformation is improved, but the deformation resistance is reduced when repeated buckling deformation occurs
Solution Approach 1:
The patent optimizes the resin's mechanical parameters, particularly tensile breaking elongation (80% or more) and viscosity, to allow the material to stretch and deform elastically during buckling cycles without breaking or becoming permanently rigid. This enables the resin to maintain deformation resistance while permitting repeated bellows formation during axial compression.
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 enhances collision energy absorption performance by enabling repeated buckling deformation in the form of bellows, improving the energy absorption effect without reducing deformation resistance, as demonstrated by axis crush deformation tests.
Implementation Method 1
a resin (11) that fills a closed cross section space, wherein the resin includes a rubber-modified epoxy resin and a curing agent, and the resin has tensile breaking elongation of 80% or more, adhesive strength to the tubular member (3) and closed cross section space forming wall part (9) of 12 MPa or higher
Data Source
AI summary
A crashworthiness energy absorption part includes: a tubular member having tensile strength of 590 to 1180 MPa grade; a closed cross section space forming wall part having tensile strength lower than the tubular member and having both edge portions joined to inner surfaces of a pair of side wall portions of the tubular member, and forming a closed cross section space between the closed cross section space forming wall part and a part of a peripheral wall portion of the tubular member; and a resin configured to fill the closed cross section space, includes a rubber-modified epoxy resin and a curing agent, and has tensile breaking elongation of 80% or more, adhesive strength to the tubular member and closed cross section space forming wall part of 12 MPa or higher, and a compression nominal stress of 6 MPa or higher at a compression nominal strain of 10%.