Vehicle Frame Corner Structure for Controlled Crash Deformation
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Solution Overview
Problem
High-strength materials used in frame members for vehicle bodies face challenges in achieving controlled deformation modes during collisions, leading to localized deformation and reduced energy absorption performance.
Innovation Solution
A frame member design with a deformation starting portion having specific hardness and hardness distribution, including a protruding shape and controlled microstructure, to ensure reliable bending deformation and improved impact absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high strength material is used for frame member to achieve weight reduction, then weight is reduced and strength is improved, but deformation control becomes difficult and energy absorption performance deteriorates
Solution Approach 1:
The invention applies local quality by creating a deformation starting portion with different hardness properties (330-450 Hv) at a specific location (corner section) of the frame member, while the rest of the member maintains high strength material properties. This localized hardness modification enables controlled deformation initiation at the corner section during collision, solving the contradiction between overall high strength and localized deformation control.
2Ease of manufacture
If deformation starting portion is formed in high strength material, then deformation initiation is promoted, but localized deformation occurs and expected deformation mode cannot be realized
Solution Approach 1:
The invention changes the physical parameter of hardness at the deformation starting portion by creating a localized region with 330-450 Hv hardness, which is lower than the base high strength material. This parameter change allows deformation to initiate reliably at the corner section while the controlled hardness range prevents excessive localization, enabling the frame member to achieve the expected deformation mode during collision.
3Strength
If high strength material is used, then load resistance is improved, but elongation property deteriorates and crack occurrence increases during deformation
Solution Approach 1:
The invention applies local quality by creating a deformation starting portion with different hardness properties (330-450 Hv) at a specific location (corner section) of the frame member, while the rest of the member maintains high strength material properties. This localized hardness modification enables controlled deformation initiation at the corner section during collision, solving the contradiction between overall high strength and localized deformation control.
4Loss of energy
If deformation starting portion is formed, then energy absorption is improved, but deformation becomes localized and expected deformation mode cannot be achieved
Solution Approach 1:
The invention changes the physical parameter of hardness at the deformation starting portion by creating a localized region with 330-450 Hv hardness, which is lower than the base high strength material. This parameter change allows deformation to initiate reliably at the corner section while the controlled hardness range prevents excessive localization, enabling the frame member to achieve the expected deformation mode during collision.
Data Source
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AI summary
This frame member includes a corner section extending along the longitudinal direction; a first wall section extending from an end portion of the corner section in a direction orthogonal to the longitudinal direction; and a second wall section extending from an opposite end portion of the corner section, wherein the corner section is formed with a deformation starting portion from which a deformation starts when a load is input to the frame member in the longitudinal direction, the deformation starting portion having a shape protruding to an inner bending side or an outer bending side of the corner section, and an average hardness value H(K1) at a first region is equal to or greater than 330 Hv in Vickers hardness, and a 3-sigma range of a standard deviation σ in a frequency distribution of the hardness at the first region is equal to or greater than 60, the first region being located at a portion outwardly apart from an end portion of the deformation starting portion in the longitudinal direction by 10 mm in the longitudinal direction, at a depth of 1/4 thickness of the frame member from a surface.