Transient Contact Elastic–Plastic Characteristics Analysis of Rail Welded Joints in Heavy-Haul Railways

TL;DR

This study examines how rail welded joints behave under heavy-haul train conditions, revealing how contact mechanics and material properties affect wear and damage.

Contribution

The study reveals the coupling law of contact behavior, dynamic response, and material failure in rail welded joints.

Findings

Contact state shifts from stick-slip to slip in welded zones, increasing wear susceptibility.

Plastic deformation initiates at the rail surface due to stress–strain concentration at key damage sites.

Increasing yield strength and reducing wheelset velocity or friction coefficient mitigates plastic deformation.

Abstract

What are the main findings?

Contact state shifts from stick-slip to slip in welded zones, increasing wear susceptibility.

Plastic deformation initiates at the rail surface due to stress–strain concentration at key damage sites.

Parametric analysis assesses and ranks parameter effects on damage initiation.

What are the implications of the main findings?

Guides welded joint material selection and parameter optimization for durability.

Supports targeted rail surface maintenance and damage-prevention strategies.

Informs operational adjustments (speed, mass, friction) to reduce plastic deformation.

This study investigates the transient wheel–rail contact mechanics of welded joints in heavy-haul rails via a validated 3D finite element model, and analyzes the stick-slip behavior, dynamic response and elastoplastic characteristics in the base material zone, heat-affected zone and weld bead zone. Results show a distinct contact state transition from stick-slip in the base material to predominant slip within the welded zones, indicating higher wear susceptibility. Dynamic response analysis reveals the highest and lowest contact-point acceleration amplitudes in the base material and heat-affected zone, respectively, due to material heterogeneity. Plastic deformation consistently initiates at the rail surface, where stress and strain concentrate, establishing it as the primary site for damage nucleation. A systematic parametric study shows that plastic deformation can be effectively mitigated by increasing the yield strength and elastic modulus of the welded joint material, or reducing the wheelset velocity, unsprung mass and wheel–rail friction coefficient. In contrast, adjusting the primary suspension and fastener parameters exerts a negligible influence on plastic deformation control. These findings provide a mechanistic basis for optimizing the performance and maintenance of welded joints in heavy-haul rail operations. This study reveals the coupling law of multiple mechanisms among contact behavior, dynamic response and material failure during the damage initiation process of rail welded joints from the mechanistic perspective, which provides a theoretical basis for the structural optimization, condition assessment and maintenance of rail welded joints in heavy-haul railways.

Figures