Variable-Strength Vehicle Pillar for Impact Absorption and Formability
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Solution Overview
Problem
Automotive pillars face challenges in meeting strength and ductility requirements under varying directional stresses without increasing weight, as existing treatments often result in parts that are too hard and difficult to shape and connect.
Innovation Solution
A method of constructing a vehicle pillar with variable gauges and tensile strengths, involving a reinforced section, a middle portion, and sidewalls with distinct gauges and tensile strengths, achieved through selective material addition and treatment techniques such as press hardening and heat treating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If localized areas of a part are heated to change physical and chemical properties, then strength and ductility are improved, but the part becomes too hard and difficult to shape and connect
Solution Approach 1:
The patent applies local quality by creating distinct zones within the pillar structure with different material properties. The transition zone has different tensile strength than the middle portion, allowing each zone to be optimized for its specific functional requirements. This enables the harder, stronger treated zones to coexist with more ductile, easier-to-form zones without compromising overall performance.
Solution Approach 2:
The patent utilizes parameter changes by varying the tensile strength parameter across different portions of the pillar. Through selective heat treatment and material composition adjustment, the transition zone is given different tensile strength parameters compared to the middle portion, enabling optimized performance for both strength and manufacturability in different regions.
2Weight of moving object
If thinner gauge metal is used to reduce weight, then fuel efficiency is improved, but the part may not meet strength standards under varying directional stresses
Solution Approach 1:
The patent applies local quality by concentrating the thinnest gauge metal in the middle portion where weight reduction is prioritized, while using thicker, stronger material in the transition zone and sidewalls where structural integrity is critical. This allows the pillar to meet strength standards under varying directional stresses while minimizing overall weight.
Solution Approach 2:
The patent effectively creates a composite structure by combining metal portions with different gauges and tensile strengths within a single pillar. The transition zone acts as a composite interface between the thinner middle portion and the thicker sidewalls, integrating multiple material properties to achieve both weight reduction and strength requirements.
3Ease of manufacture
If uniform gauge metal is used throughout the pillar, then manufacturing is simplified, but the pillar cannot optimally handle varying directional stresses in different portions
Solution Approach 1:
The patent applies local quality by assigning different gauges and tensile strengths to different portions of the pillar based on their specific stress requirements. The transition zone has different properties than the middle portion and sidewalls, allowing each area to be optimized for its local stress conditions while maintaining overall structural coherence.
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 the creation of a strong and lightweight pillar that effectively absorbs impacts and distributes weight, while maintaining suitable ductility and ease of assembly, thus addressing the challenges of varying directional stresses without weight increase.
Implementation Method 1
modifying the tensile strength of the transition... achieved through selective material addition and treatment techniques such as press hardening and heat treating
Data Source
AI summary
A pillar for a vehicle including at least two different localized areas of different tensile strengths. The pillar includes a body defining a width that merges into sidewalls at a transition. The body having a first tensile strength and the transition has a second tensile strength, wherein the first tensile strength is smaller than the second tensile strength. The variety in tensile strength resulting from at least one of varying the material treatment and varying the gauge. The pillar is press-hardened until it reaches a tensile strength of 1500 MPa to 2000 MPa.