Roll-Bent Underframe Boundary Beam for Drum-Shaped Railway Vehicles
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Solution Overview
Problem
Conventional underframe boundary beams with channel steel are unsuitable for drum-shaped vehicle bodies, leading to increased processing and assembly difficulties, weight, and fatigue stress at the joint of the side wall stand column and floor, due to their small height and complex mounting requirements for under-vehicle equipment.
Innovation Solution
A roll-bent underframe boundary beam with a channel structure, featuring an inclined side face, concave platen for butt welding with the side wall plate, and a vertical flanging for improved rigidity and mounting of under-vehicle equipment, reducing fatigue stress and assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional channel steel 18b-Q235B is used for underframe boundary beam, then the structure is simple to manufacture, but the height size is small making it unsuitable for boundary beam hanging and drum-shaped vehicle bodies
Solution Approach 1:
The boundary beam transitions from conventional channel steel 18b with small height to a roll-bent structure with significantly increased height (200-300mm). This parameter change in height enables the beam to accommodate drum-shaped vehicle bodies and support boundary beam hanging, while maintaining manufacturing feasibility through roll-bending technology.
2Strength
If cross beams are inserted into boundary beam channel and welded, then the structural connection is achieved, but the processing difficulty and assembly difficulty are high
Solution Approach 1:
The connection structure is segmented into distinct functional elements: the boundary beam with integrated connection plates, separate cross beams, and standardized welding interfaces. This segmentation allows for simplified individual component manufacturing and easier assembly through pre-fabricated connection details, reducing overall processing and assembly difficulty while maintaining structural strength.
3Strength
If the section of outer cross beam and inner cross beam near boundary beam is made large, then the structural strength is improved, but the weight is heavy and lightweight of vehicle body is not facilitated
Solution Approach 1:
The cross beam sections are optimized with local quality variation: larger section dimensions are provided only at critical locations near the boundary beam where high strength is required for structural support, while the central portions of the cross beams use reduced section dimensions. This localized strengthening approach maintains necessary structural strength while minimizing overall weight, facilitating vehicle body lightweighting.
4Strength
If the lower end of stand column is provided with seam allowance and welded to floor, then the connection is achieved, but the processing volume is increased and fatigue stress near welding seam is increased
Solution Approach 1:
The stand column connection is extracted from the floor structure and repositioned to connect directly to the boundary beam. This extraction eliminates the need for seam allowances and reduces processing volume, while the direct connection to the boundary beam maintains connection strength. The separation of the stand column from the floor also reduces fatigue stress concentration at the welding seam.
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 simplifies the assembly and reduces the weight of the vehicle body while enhancing the flatness of the side wall and reducing fatigue stress at the joint, making it suitable for drum-shaped vehicle bodies and facilitating the mounting of under-vehicle equipment.
Implementation Method 1
reducing fatigue stress at the joint of a side wall stand column and the floor
Data Source
AI summary
An underframe boundary beam connecting structure suitable for a railway vehicle with a drum-shaped vehicle body is provided. An underframe boundary beam is a through long roll bending piece, a section of the through long roll bending piece is of a channel structure, and has a side face, an upper wing face, and a lower wing face. The side face has an inclination angle consistent with a side wall plate, an upper end of an outer side of the side face is provided with a concave platen, and the side wall plate is lapped on the concave platen and fixed by a butt welding; an inner end of the lower wing face is provided with a downwards vertical flanging, a vertical plate is welded and fixed between the upper wing face and the lower wing face.