Composite Rail Coach Beam Connection for Lower Structural Mass
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Solution Overview
Problem
Conventional rail vehicle coach bodies face issues with structural mass, corrosion susceptibility, and manufacturing inaccuracies due to the use of conventional materials, leading to increased maintenance and reduced load capacity, especially in high-frequency operation environments like underground and suburban railways.
Innovation Solution
The coach body is partially or entirely made of fibre-reinforced plastic composite materials, particularly carbon-fibre composites, with a high percentage of fibre-reinforced plastics used in load-bearing components to reduce structural mass and increase load capacity, while minimizing corrosion and maintenance through friction- and material-bonded connections and pultrusion processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional steel and lightweight steel profiles are used for the coach body structure, then the structural strength and rigidity are sufficient, but the structural mass is high and corrosion susceptibility increases
Solution Approach 1:
The patent applies composite materials by using fibre-reinforced plastic (FRP) components, specifically pultruded profiles with embedded steel reinforcement bars, to replace conventional steel structures. This composite approach reduces structural mass while maintaining strength through the synergistic combination of lightweight FRP and high-strength steel reinforcement.
Solution Approach 2:
The patent changes material parameters by transitioning from solid steel profiles to pultruded FRP profiles with embedded reinforcement. This parameter change involves altering the material composition, density, and structural configuration to achieve reduced mass while preserving load-bearing capacity through optimized fiber orientation and steel bar placement.
2Strength
If conventional steel and lightweight steel profiles are used for the coach body structure, then the structural strength and rigidity are sufficient, but corrosion susceptibility increases leading to increased maintenance
Solution Approach 1:
The patent uses composite materials where fibre-reinforced plastic encapsulates steel reinforcement bars, creating a corrosion-resistant structure. The FRP matrix protects the steel from environmental exposure, eliminating direct contact with corrosive elements while maintaining the structural strength provided by the steel reinforcement.
Solution Approach 2:
The fibre-reinforced plastic acts as an intermediary protective layer between the steel reinforcement bars and the corrosive environment. This intermediate FRP matrix prevents direct exposure of steel to moisture and chemicals, thereby preventing corrosion while allowing the steel to fulfill its load-bearing function.
3Ease of manufacture
If segment modules are connected by screwed or riveted connections, then the assembly is feasible, but the danger of crevice corrosion in the connection zone is greatly increased
Solution Approach 1:
The patent employs composite material connections where FRP components are joined using methods that eliminate crevice formation. The pultruded FRP profiles with embedded steel bars allow for continuous, seamless connections that prevent crevice corrosion, maintaining both assembly feasibility and corrosion resistance.
Solution Approach 2:
The patent extracts traditional metal-to-metal connection methods (screws and rivets) that create crevices, replacing them with connection approaches specific to composite materials. This extraction of harmful connection methods eliminates the crevice corrosion problem while preserving structural integrity through alternative joining techniques suitable for FRP components.
4Weight of moving object
If fibre-reinforced plastic composite materials are used for the coach body, then the structural mass is reduced and load capacity is enhanced, but new connection methods must be developed
Solution Approach 1:
The patent uses composite materials with embedded steel reinforcement bars that facilitate conventional connection methods. The steel bars within the FRP profiles allow for straightforward mechanical connections similar to traditional steel structures, reducing the complexity of developing new connection methodologies while maintaining the weight benefits of composite materials.
Solution Approach 2:
The embedded steel reinforcement bars serve as intermediaries that enable conventional connection techniques. These steel elements act as mediators between the FRP composite structure and traditional connection methods, allowing for simplified joining processes without requiring entirely new connection technologies for composite materials.
Data Source
AI summary
A device for connecting a cross member for receiving pivot pins on two lower longitudinal members of a car body for a rail vehicle. The cross member has a transversal part that connects the two longitudinal members to each other in the region of the connection, and a longitudinal part that extends to the closest car front. The lower longitudinal members extend over the complete length of the car body and consist of multi-chamber hollow profiles made of a fibre composite material. The number of chambers of the multi-chamber hollow profile of each longitudinal member is reduced in the region of the connection such that the wall material of at least one chamber was removed in such a way that the webs to the adjacent chambers are exposed. At these places, load-introducing elements engage, to which load-introducing elements the cross member is attached.