Lateral Longitudinal Beam with Local Induction Hardening
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Solution Overview
Problem
Existing floor-panel structures for motor vehicles face challenges in balancing the need for stability under head-on impacts and ductility during lateral collisions, while also being lightweight and cost-effective to manufacture, as they require complex spot welding processes and heavier structures to achieve the necessary resistance and deformation characteristics.
Innovation Solution
The use of a single sheet-element steel for lateral longitudinal beams, where the front portion is reinforced through high-frequency induction heating to enhance resistance to axial loads, and the remaining portion is made ductile to absorb impact energy, eliminating the need for complex welding and reducing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If complex spot welding processes and heavier structures are used, then resistance to axial loads is improved, but manufacturing complexity and weight increase
Solution Approach 1:
The patent applies local thermal treatment (heating and quenching) to change the material parameters of the front portion of the longitudinal beam, transforming it from a uniform structure to one with spatially varying properties. This allows the front portion to achieve high strength and ductility equivalent to complex welded structures, while the rest of the beam remains lighter and simpler to manufacture.
2Ease of manufacture
If a uniform structure is used throughout the longitudinal beam, then manufacturing is simplified, but the ability to withstand head-on impacts and absorb lateral impact energy is compromised
Solution Approach 1:
The patent implements local quality by applying thermal treatment only to the front portion of the longitudinal beam, creating a gradient of material properties along its length. The front portion gains enhanced strength and ductility for impact resistance, while the rear portion maintains uniform, simpler characteristics for easy manufacturing. This resolves the contradiction by optimizing different regions for different functions.
3Reliability
If the entire longitudinal beam is made ductile, then lateral impact energy absorption is improved, but head-on impact resistance is reduced
Solution Approach 1:
The patent uses thermal treatment to change the material parameters (strength, ductility, hardness) of the front portion while leaving the rest of the beam unchanged. This creates a functional gradient where the front portion is optimized for both head-on impact resistance and lateral energy absorption, and the rear portion maintains appropriate mechanical properties for structural support, resolving the contradiction between these opposing requirements.
4Stability of the object's composition
If heavier structures are used, then structural stability is improved, but weight and manufacturing cost increase
Solution Approach 1:
The patent applies local thermal treatment to create spatially varying material properties, concentrating enhanced strength and stability characteristics only where needed (front portion for impact zones) while maintaining lighter weight in non-critical areas. This achieves necessary structural stability without the penalty of uniform heavy construction throughout the entire beam.
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
This approach allows for a lighter, simpler, and cheaper manufacturing process while maintaining the necessary resistance and deformability, ensuring passenger compartment integrity and safety without the risk of fractures or fragments during collisions.
Implementation Method 1
said reinforced front portion of each lateral longitudinal beam is constituted by a hardened portion obtained by subjecting only the front portion of said single sheet element made of steel to a thermal treatment by means of high-frequency induction heating
Implementation Method 2
subjecting only the front portion of said single sheet element made of steel to a thermal treatment
Data Source
AI summary
A floor-panel structure for a vehicle includes a front body subassembly, a front floor structure, including a central longitudinal tunnel, two lateral longitudinal beams, connected to the floor structure and the body subassembly, and two intermediate longitudinal beams, which connect the floor structure to the body subassembly and extend in areas between the lateral longitudinal beams and central longitudinal tunnel. The lateral longitudinal beams each include a sheet-metal profile element having an open cross section, a front portion reinforced for withstanding relatively high axial loads, and a remaining portion that is more ductile than said front portion so as to be more liable to collapse. Each lateral longitudinal beam is constituted by a single sheet element of steel, and said reinforced front portion is constituted by a hardened portion obtained by subjecting only the front portion to a thermal treatment using high-frequency induction heating.