Vehicle Frame Member Structure With Softened Layer for Impact Absorption
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Solution Overview
Problem
Vehicle body structures with frame members made of high-strength materials, such as high-tensile steel, face limitations in achieving both enhanced deformation capability and load resistance, as existing solutions primarily focus on improving one aspect at the expense of the other.
Innovation Solution
A vehicle body structure design featuring a frame member with a specific configuration, including a first top plate section, corner sections, vertical wall sections, and support sections, where a softened layer is strategically applied to enhance deformation capability and load resistance by controlling hardness and thickness gradients within the frame member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high-strength material such as high-tensile steel sheet is used for frame members, then load resistance is improved, but deformation capability deteriorates
Solution Approach 1:
The patent applies local quality by creating a softened layer with different hardness properties at specific locations on the frame member surface. The softened layer has a hardness of 300-400 Hv, while the base material maintains high strength with hardness ≥400 Hv. This localized property differentiation allows the frame member to exhibit both high load resistance (from the hard base material) and good deformation capability (from the softer surface layer) in the same component.
Solution Approach 2:
The patent effectively creates a composite structure by combining the softened layer (with lower hardness for deformation) and the base high-strength material (with higher hardness for load resistance). This composite approach allows the frame member to possess dual characteristics: the softened layer provides deformation capability while the underlying high-strength material provides load resistance, resolving the contradiction between these two properties.
2Ease of manufacture
If a softened layer is provided on the frame member to improve deformation capability, then deformation capability is improved, but load resistance deteriorates
Solution Approach 1:
The softened layer is applied locally rather than uniformly across the entire frame member. By controlling the thickness (0.01-0.5 mm) and hardness (300-400 Hv) of the softened layer while maintaining the base material's high strength, the patent achieves deformation capability where needed without compromising overall load resistance. The localized application ensures that critical load-bearing areas retain their strength while deformation-prone areas gain flexibility.
Solution Approach 2:
The patent resolves the contradiction by precisely controlling the parameters of the softened layer: hardness (300-400 Hv), thickness (0.01-0.5 mm), and surface hardness ratio (0.7-0.9 times the central section hardness). These parameter optimizations ensure that the softened layer provides sufficient deformation capability while the underlying high-strength material maintains load resistance, preventing the deterioration of strength.
3Ease of manufacture
If the hardness of the softened layer is reduced to enhance deformation capability, then deformation capability is improved, but surface strength deteriorates
Solution Approach 1:
The patent optimizes the hardness parameter of the softened layer to fall within 300-400 Hv, which is softer than the base material (≥400 Hv) but not excessively soft. Additionally, the surface hardness is controlled to be 0.7-0.9 times the central section hardness, creating a gradual hardness gradient. This parameter optimization allows the softened layer to provide deformation capability while maintaining sufficient surface strength to prevent premature failure.
Data Source
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AI summary
This vehicle body structure includes a frame member with a first top section, a corner section, a vertical wall section, and a second top section, and a first support section and a second support section provided at the second top section. L/h ≤ 6.7 is satisfied where the h represents a length between an outer surface of the first top section and an outer surface of the second top section, and the L represents a length between the first support section and the second support section.