Deformable Rear Crossmembers with Special Extrusion Section Design
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Solution Overview
Problem
Current vehicle subframe structures face challenges in effectively managing impact forces during frontal crashes while balancing weight reduction and safety considerations, as existing designs often compromise on crash safety and efficiency.
Innovation Solution
A multicell support extrusion structure for vehicle subframes, featuring a front cell column with triggers that deform plastically downward in a vertical direction upon impact, coupled with a rear crossmember, enhances energy absorption and maintains structural integrity during frontal crashes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional rigid subframe structures are used, then structural strength is maintained, but weight increases and crash energy absorption efficiency decreases
Solution Approach 1:
The subframe structure is divided into multiple cells (front cell, middle cell, rear cell) with distinct functions. The front cell contains deformable triggers for energy absorption, the middle cell provides structural support, and the rear cell connects to the vehicle body. This segmentation allows different regions to optimize for either strength or weight reduction as needed.
Solution Approach 2:
The front cell column is designed with variable wall thickness and includes trigger mechanisms that change the structural parameters during crash events. The triggers are positioned at specific locations to initiate controlled deformation, changing the stiffness and energy absorption characteristics of the structure dynamically during impact.
2Reliability
If heavier subframe structures are used, then crash safety is improved, but weight reduction goals are compromised
Solution Approach 1:
The deformable triggers in the front cell are designed to fail in a controlled manner during crashes, converting the harmful impact energy into beneficial plastic deformation. This controlled failure mechanism absorbs crash energy while protecting the passenger compartment, turning the potential weakness of lighter structures into a safety advantage.
Solution Approach 2:
The subframe employs aluminum alloy materials that provide high strength-to-weight ratio. The combination of aluminum alloy with the multicell structural design creates a composite-like system that achieves both weight reduction and crash safety performance.
3Loss of energy
If deformable triggers are added to the front cell, then energy absorption is enhanced, but manufacturing complexity increases
Solution Approach 1:
The triggers are pre-formed during the extrusion manufacturing process rather than being added as separate components. The extrusion die is designed to create the trigger geometry and wall thickness variations directly in the front cell column, so the complex deformation mechanisms are built into the structure before assembly.
Solution Approach 2:
The trigger mechanisms are integrated into the front cell column structure itself rather than being separate components. The wall thickness variations and geometric features that create the trigger effects are combined with the load-bearing structure, eliminating the need for additional parts while maintaining energy absorption functionality.
4Loss of energy
If the front cell column deforms plastically during crash, then impact forces are absorbed, but structural integrity may be compromised
Solution Approach 1:
The multicell structure segments the deformation zones from the intact structural zones. The front cell is designed to deform plastically to absorb energy, while the middle and rear cells maintain their structural integrity to support the vehicle body and protect the passenger compartment.
Solution Approach 2:
Different regions of the subframe have different structural qualities optimized for their specific functions. The front cell has thinner walls and trigger features for energy absorption, while the middle and rear cells have thicker walls and stronger connections for structural support and integrity maintenance.
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 multicell support extrusion effectively absorbs impact forces, reducing the risk of detachment and maintaining structural integrity, thereby enhancing passenger safety and mitigating crash impacts without compromising on weight reduction or increasing manufacturing complexity.
Implementation Method 1
a trigger that facilitates plastically deforming the front cell column downward in a vertical direction of the subframe structure when subjected to impact forces of a frontal crash
Data Source
AI summary
A support extrusion for a subframe structure of a vehicle and methods of fabricating the same. In one example, a support extrusion can comprise a multicell structure that facilitates coupling the support extrusion with a rear crossmember of the subframe structure. The multicell structure can comprise a front cell column and a rear cell column that intervenes between the front cell column and the rear crossmember in a longitudinal direction of the subframe structure. The front cell column can comprise a trigger that facilitates plastically deforming the front cell column downward in a vertical direction of the subframe structure when subjected to impact forces of a frontal crash.