Rail Vehicle Floor Structure with Non-Permanent Fasteners
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Solution Overview
Problem
The existing methods for installing and removing passenger floors in rail vehicles are labor-intensive due to the use of thick adhesives and require complex processes, especially since the supporting structure is not flat, necessitating the use of intermediate structures or rigid mounts which complicate the process.
Innovation Solution
A floor structure for rail vehicles comprising longitudinal and transverse structural members with non-permanent, reclosable fasteners that create a flat mounting plane, allowing for direct and repeatable attachment and removal of the floor panel without damaging the supporting structure, using low-heat joining processes like laser welding and friction-stir welding to ensure flatness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thick layer of adhesive is used to fix the passenger floor to the supporting structure, then the floor can be attached to an uneven supporting structure, but the removal process becomes labor-intensive and requires cutting and cleaning operations
Solution Approach 1:
The adhesive layer is segmented into multiple thickness zones, with thicker adhesive at edges and corners providing reinforcement, and thinner adhesive in central areas. This segmentation allows the floor to be attached to uneven surfaces while enabling cleaner removal compared to uniformly thick adhesive applications.
Solution Approach 2:
The adhesive thickness parameter is varied across different locations of the floor assembly. By controlling the thickness distribution rather than using a uniform layer, the system achieves both adequate bonding on uneven surfaces and improved removability through reduced adhesive volume in critical areas.
2Productivity
If the supporting structure is used as-is from welding operations, then manufacturing is simpler, but the structure is not sufficiently flat to directly attach the passenger floor
Solution Approach 1:
An intermediate adhesive layer is introduced between the as-welded supporting structure and the passenger floor. This intermediary layer compensates for the unevenness of the supporting structure, allowing direct attachment of the floor without requiring additional machining or flattening operations on the supporting structure itself.
Solution Approach 2:
The adhesive layer thickness is optimized to bridge the gap between the uneven supporting structure and the floor requirements. By adjusting the adhesive thickness parameter, the system achieves the necessary flatness for floor attachment while maintaining manufacturing simplicity of the supporting structure.
3Manufacturing precision
If an intermediate structure with resilient mounts is used to compensate for supporting structure unevenness, then the floor can be attached to non-flat surfaces, but the solution becomes more expensive and complex
Solution Approach 1:
The complex intermediate structure with resilient mounts is extracted and replaced by a simpler adhesive-based solution. The adhesive layer directly provides the necessary compliance and thickness variation to accommodate supporting structure unevenness, eliminating the need for separate mechanical mounting intermediaries.
Solution Approach 2:
The adhesive layer serves as a cost-effective, consumable element that absorbs the complexity of accommodating supporting structure variations. Rather than investing in expensive, complex mechanical intermediate structures, the system uses a simpler adhesive solution that can be applied and removed more easily.
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
Enables easy and residue-free installation and removal of the passenger floor, reducing labor and damage to the supporting structure, with a flatness tolerance of 3 mm per meter, and incorporating damping elements for vibration absorption.
Implementation Method 1
low-heat joining processes like laser welding
Implementation Method 2
low-heat joining processes like laser welding and friction-stir welding
Implementation Method 3
incorporating damping elements for vibration absorption
Data Source
Figure 1
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Figure 4
AI summary
A floor structure of a rail vehicle car body comprises a supporting structure having a left and a right longitudinal beams and a plurality of transverse structural members using a low-heat welding process. A floor panel is directly and releasably attached atop the supporting structure using and a plurality of non-permanent, pressure interlocking fasteners.