Variable Strength Vehicle Side Rail for Collision Energy Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle side rails lack controlled deformation mechanisms to effectively absorb high-speed collision energy while minimizing deformation in low-speed collisions, and they often require complex designs to achieve this.
Innovation Solution
A high-strength steel side rail with a projecting end exceeding 1400 MPa tensile strength and strategically positioned softer portions with yield points below 1000 MPa, allowing for sequential energy absorption and reduced deformation risk through controlled deformation zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-strength steel with tensile strength >1400 MPa is used for the entire side rail, then the side rail strength is improved, but the side rail deforms and cracks in high-speed collisions
Solution Approach 1:
The side rail is designed with non-uniform strength distribution: the front portion (0-400mm from front end) has lower strength with yield point <1000 MPa to enable controlled deformation and energy absorption, while the rear portion has higher strength with tensile strength >1400 MPa to maintain structural integrity. This local quality differentiation resolves the contradiction by allowing the front to deform reliably in high-speed collisions while the rear maintains overall strength.
2Loss of energy
If soft portions are added to enable controlled deformation, then energy absorption in high-speed collisions is improved, but the side rail deforms in low-speed collisions
Solution Approach 1:
The strength parameter of the side rail is changed along its length, creating a gradient from lower strength at the front (yield point <1000 MPa) to higher strength at the rear (tensile strength >1400 MPa). This parameter change enables the front to yield in high-speed collisions for energy absorption, while the overall high strength prevents deformation in low-speed collisions.
3Loss of energy
If the front portion has lower strength to enable deformation, then energy absorption is improved, but the overall side rail strength decreases
Solution Approach 1:
The side rail is segmented into two functional portions: a front deformation zone (0-400mm) with lower strength for energy absorption, and a rear structural zone with high strength for maintaining overall rail strength. This segmentation allows each portion to perform its specific function while the combination achieves both energy absorption and overall strength requirements.
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 enables controlled deformation in high-speed collisions and minimizes damage in low-speed collisions by utilizing high-strength steel with strategically designed softer sections, enhancing energy absorption and simplifying vehicle design.
Implementation Method 1
high-strength steel tends to crack when it is deformed
Implementation Method 2
the front portion of the side rail has three portions which are softer, i.e. which have lower strength than the rest of the side rail
Data Source
Figure 1~2
AI summary
A side rail for vehicles has a tensile strength in excess of 1400 MPa and has one end (16) projecting from the safety cage of the vehicle and adapted to carry a bumper. The end projecting from the safety cage has lower strength with a yield point of less than 1000 MPa over a length of at least 0.4 m. It has an outer portion with a length of at least 0.2 m and a tensile strength below 800 MPa and an inner portion with a higher tensile strength than the outer portion.