Vehicle Subframe Cross-Section Layout for Stiffness and Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing subframe configurations for vehicles face challenges in improving flexibility in setting support stiffness for suspension members while avoiding stress concentration and ensuring adequate strength.
Innovation Solution
The subframe design includes a first crossmember with a closed cross-section, a lower member with an outer-side, middle, and inner-side portion, and adjacently-positioned closed cross-sections that optimize strength and stiffness balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a closed cross-section bracket is used to ensure strength, then stress concentration increases at the inner-side end portion, but if the closed cross-section is opened to reduce stress concentration, then structural strength decreases
Solution Approach 1:
The lower member employs different cross-sectional configurations at different locations: closed cross-sections at the outer-side and inner-side portions for strength, and an open cross-section at the middle portion where stress concentration would occur. This local variation in structural quality allows the member to maintain overall strength while reducing stress concentration at critical locations.
Solution Approach 2:
The lower member transitions from rigid closed cross-sections to a more flexible open cross-section configuration at the middle portion. This dynamic structural adaptation allows the member to be rigid where strength is needed and more compliant where stress concentration should be reduced, optimizing the balance between strength and stress distribution.
2Adaptability or versatility
If the bracket area is increased to improve strength, then flexibility in setting support stiffness for suspension members is reduced, but if the area is decreased to improve stiffness flexibility, then strength is compromised
Solution Approach 1:
The lower member uses different cross-sectional configurations at different locations to provide both strength and stiffness flexibility. The closed cross-sections at the ends provide strength, while the open cross-section at the middle portion allows for adjusted stiffness characteristics, enabling flexible suspension member support without compromising overall structural integrity.
Data Source
AI summary
In a lower member of a subframe for a vehicle, a middle portion between an outer-side portion and an inner-side portion includes an outer-side curved bottom portion and an inner-side curved bottom portion. Adjacently-positioned closed cross-sections are provided corresponding to at least a portion of the outer-side curved bottom portion and the inner-side curved bottom portion, the adjacently-positioned closed cross-sections being made up of a first closed cross-section of a first crossmember and a second closed cross-section of the lower member positioned adjacent to each other in a vertical direction in such a manner as to be divided by a wall portion of the first crossmember and next to each other, the wall portion defining the first closed cross-section.