Innovative Application of CFRT Prepreg Unidirectional Tape in High-Performance Rail Transit Structures
Release time:
2025-11-19
Author:
Source:
Introduction
With the rapid development of urban rail transit and high-speed railways, lightweight design, high strength, and high durability have become core objectives in the design and manufacturing of rail transit vehicles. Train structural components must not only meet safety requirements at high speeds but also resist fatigue, vibration, and climatic environmental impacts during long-term operation.
Although traditional steel structures and aluminum alloys possess a certain level of strength, they have limitations in terms of lightweight performance, complex structural forming, and fatigue resistance. To meet the future demands for higher speed, higher load capacity, and higher reliability, the rail transit industry is actively seeking new material solutions. Continuous Fiber Reinforced Thermoplastic (CFRT) prepreg unidirectional tape, with the high strength of continuous fibers and the processability of thermoplastic matrices, has emerged as an ideal choice for lightweight structural design in rail transit.
This paper comprehensively explores the application of CFRT in high-performance rail transit structures from aspects such as material properties, manufacturing technologies, typical applications, performance optimization, economic and environmental benefits, and future development trends, aiming to provide references for rail transit enterprises and research institutions.
I. Lightweight and High-Performance Requirements in Rail Transit
1.1 Lightweight Requirements for High-Speed Trains
As the speed of high-speed trains continues to increase, train weight directly affects energy consumption, braking performance, track wear, and the load on power systems. Lightweight design can:• Reduce overall vehicle energy consumption and improve operational efficiency;• Enhance train acceleration and braking response capabilities;• Minimize track wear and maintenance costs;• Optimize the ratio of passenger and cargo capacity to maximize economic benefits.
Lightweight design not only requires materials to be lightweight but also to ensure strength, stiffness, and fatigue resistance.
1.2 Requirements for High Strength and Fatigue Resistance
Rail transit structural components are subjected to multiple loads such as vibration, bending, impact, and thermal expansion and contraction over the long term. In particular, structural components such as carriages, floor beams, and door structures of high-speed trains require materials to have:• High specific strength and specific stiffness;• Excellent fatigue resistance and vibration absorption capacity;• Corrosion resistance, resistance to temperature changes, and long-term reliability.
Traditional metal materials struggle to meet these requirements while reducing weight, whereas CFRT prepreg unidirectional tape can provide the dual advantages of high performance and lightweight.
II. Material Properties and Technical Advantages of CFRT Prepreg Unidirectional Tape
CFRT uses continuous fibers as reinforcements, which can significantly improve the specific strength and specific stiffness of structural components. The directional laying of continuous fibers can be optimized according to the loads on different parts:• Longitudinal laying: Enhances the bending stiffness of structures such as floor beams and carriage frames;• Transverse laying: Increases the impact resistance of components such as doors and anti-collision beams;• Multi-directional layering: Achieves high reliability of the overall structure for complex stress conditions.
The precise layup design of continuous fibers is the key to CFRT exerting its performance advantages in rail transit.
2.2 Advantages of Thermoplastic Resin Matrix
The thermoplastic resin matrix of CFRT endows the material with unique advantages:• Rapid molding and high production efficiency: Complex structural components can be formed after heating and softening;• Repairability: Damages or defects can be locally repaired by heating, reducing the scrap rate;• Recyclability: Waste materials or scrapped components can be reprocessed to achieve green manufacturing;• Adaptability to complex structures: Suitable for the integrated molding of complex geometric components such as carriage interiors, floor beams, and seat supports.
2.3 Mechanical Performance Advantages
• High specific strength and specific stiffness suitable for withstanding long-term loads of train structures;• Excellent fatigue performance extends the service life of key components;• Impact absorption performance improves passenger safety;• Thermal stability and corrosion resistance ensure long-term use of the material in humid, cold, or high-temperature environments.
III. CFRT Manufacturing Technologies and Processes
3.1 Automated Tape Laying Technology
Rail transit structural components are often large in size and complex in shape. CFRT automated tape laying technology can meet the requirements of high-precision manufacturing:• Multi-axis robotic tape laying: Controls fiber direction, tension, and laying speed;• Flexible process control: Achieves optimization of fiber density and thickness in different areas;• Online defect detection: Visually identifies bubbles, wrinkles, or deviations to realize automatic correction.
Automated tape laying technology ensures the stability and repeatability of large-size carriage structural components.
3.2 Hot Press Molding and Vacuum-Assisted Molding
• Hot press molding: Heats and presses in a mold to fully bond fibers and resin, forming high-density, high-strength structural components;• Vacuum assistance: Removes air and bubbles to improve fiber-resin bonding;• Zoned heating: Performs local heating and curing for thickness differences to reduce warpage and stress concentration.
3.3 Digital Design and Simulation Optimization
• CAD/CAM modeling: Precisely establishes models of carriage skeletons, floor beams, roof covers, and seat frames;• Finite Element Analysis (FEA): Simulates bending, vibration, impact, and fatigue loads to optimize layup and thickness;• Topology optimization: Achieves a balance between structural lightweight and maximum stiffness;• Digital twin: Real-time monitors tape laying and molding processes during production to improve quality consistency.
3.4 Intelligent Quality Control
• Sensor monitoring: Real-time collects temperature, pressure, and tension data;• Machine vision inspection: Identifies bubbles, wrinkles, and fiber deviations;• Closed-loop feedback: Adjusts tape laying and molding processes based on real-time data to ensure component performance meets design requirements.
IV. Typical Applications of CFRT in Rail Transit
4.1 Carriage Skeletons
• CFRT continuous fibers are laid along the stress direction to improve the bending stiffness of carriages;• Integrated hot press molding reduces the number of parts and improves assembly efficiency;• Achieves an overall carriage lightweight of approximately 15–20%, reducing energy consumption and improving passenger-carrying efficiency.
4.2 Floor Beams and Support Structures
• Longitudinal CFRT layup provides high bending stiffness, while transverse layup increases shear resistance;• Composite with foam core enhances vibration damping and energy absorption performance;• Significantly improves fatigue life to meet the long-term operation requirements of high-speed trains.
4.3 Doors and Anti-Collision Beams
• Continuous fibers are laid along key directions to improve collision energy absorption capacity;• Hot press molding ensures density and structural integrity;• Achieves a lightweight of approximately 10–15%, improving safety and passenger protection effects.
4.4 Interior and Functional Components
• Composite with foam and fabrics achieves sound insulation, vibration damping, and lightweight;• Integrated structures reduce assembly processes and improve production efficiency.
V. Performance Optimization Strategies
5.1 Optimization of Fiber Layup Direction
Adjust fiber directions according to load distribution to achieve a balance between local reinforcement and overall lightweight.
5.2 Control of Thickness and Number of Layers
Optimize the number of fiber layers and thickness through digital simulation to maximize strength and stiffness while reducing weight.
5.3 Multi-Material Composite Design
CFRT can be compounded with foam, metals, or fabrics to achieve functions such as energy absorption, collision resistance, sound insulation, and heat insulation, improving overall vehicle comfort and safety.
5.4 Selection of Thermoplastic Matrix
Choose high-performance resins such as PEEK and PEI according to long-term environmental conditions to ensure corrosion resistance, high-temperature resistance, and fatigue resistance.
VI. Economic and Environmental Benefits
6.1 Economic Benefits
• Reduces overall vehicle weight and improves energy utilization efficiency;• Automated tape laying and hot press molding shorten production cycles and reduce labor costs;• Recycling and local repair reduce waste consumption and enhance economic efficiency.
6.2 Environmental Benefits
• Lightweight design reduces operational energy consumption and carbon emissions;• Recyclable thermoplastic matrices promote green manufacturing;• Meets the low-carbon development and sustainable development strategies of the rail transit industry.
VII. Technical Challenges and Solutions
7.1 Molding of Large-Size Structures
• Challenge: Warpage and bubbles are prone to occur in large-size structures such as carriages and floor beams;• Solution: Zoned heating, vacuum-assisted molding, and digital twin technology to improve molding precision.
7.2 Material Costs and Production Investment
• Challenge: The cost of continuous fibers and high-performance resins is relatively high;• Solution: Optimize layup design, automated production, and material recycling to reduce overall costs.
7.3 Standardization and Certification
• Challenge: Rail transit has strict certification requirements for structural components;• Solution: Establish CFRT design, production, and testing standards to ensure structural reliability and safety.
VIII. Future Development Trends
Integration of lightweight and high performance: CFRT compounded with metals, foam, and fabrics to achieve integrated structures with high stiffness, impact resistance, and vibration damping;
Intelligent manufacturing and digital twin: Integration of automated tape laying, hot press molding, and online monitoring with AI for process optimization;
Green manufacturing and recycling: Thermoplastic recycling technology to improve material utilization and reduce waste and carbon emissions;
Multi-functional integrated design: Integration of energy absorption, collision resistance, sound insulation, heat insulation, and intelligent sensing functions;
Cross-industry technological collaboration: Technology sharing with aerospace, automotive, and other industries to achieve material and process innovation.
IX. Conclusion
CFRT prepreg unidirectional tape has demonstrated important strategic value in high-performance rail transit structures:• Balanced lightweight and high strength: Continuous fibers and thermoplastic resins provide excellent specific strength and specific stiffness;• Integrated manufacturing of complex structures: Automated tape laying and hot press molding enable the production of large-size, high-precision components;• Multi-functional integration: Integration of energy absorption, collision resistance, sound insulation, heat insulation, and intelligent monitoring functions;• Green manufacturing and recycling: Recyclable thermoplastic matrices reduce carbon emissions and waste;• Technological innovation drives industrial upgrading: Intelligent manufacturing and digital design optimize production efficiency and structural performance.
With the development of digital manufacturing, intelligent control, and high-performance thermoplastic resins, CFRT prepreg unidirectional tape will play a core role in lightweight, high-performance, and green manufacturing of rail transit, providing solid material support for future rail transit structural innovation.
