Effect of wheel-rail interface parameters on contact stability in explicit finite element analysis

Area of Science:

• Computational mechanics
• Tribology
• Mechanical engineering

Background:

• Explicit finite element (FE) simulations are crucial for analyzing complex mechanical systems.
• The accuracy of these simulations is known to be sensitive to various parameters, including interface properties and time step size.
• However, the specific impact of interface parameters on explicit FE solutions for wheel-rail interaction remains under-explored in existing literature.

Purpose of the Study:

• To investigate the relationship between interface parameters and the accuracy of contact solutions in explicit FE simulations of wheel-rail interaction.
• To identify how incorrect parameter choices can negatively influence simulation outcomes.
• To propose guidelines for selecting optimal interface parameters to ensure stable and accurate contact responses.

Main Methods:

• Development and utilization of an explicit finite element model simulating a wheel rolling over a rail.
• Systematic variation of interface parameters, including contact stiffness, damping, and mesh density.
• Analysis of contact patch area and normal pressure distribution to assess solution accuracy and identify instabilities.
• Conducting a series of simulations to validate the proposed guidelines.

Main Results:

• Demonstration that inappropriate interface parameters (e.g., excessively high/low contact stiffness, coarse mesh) can lead to "contact instability."
• Observed manifestations of contact instability include amplification of contact forces and inaccurate contact responses.
• Identification of specific parameter ranges that promote stable and accurate contact solutions.
• Validation of proposed guidelines through simulation results.

Conclusions:

• The selection of interface parameters is critical for the accuracy and stability of explicit FE simulations in wheel-rail interaction.
• Suboptimal parameter choices can introduce significant errors, termed "contact instability."
• The study provides practical guidelines for selecting optimal interface parameters to achieve reliable simulation results.
• Adherence to these guidelines ensures the integrity of contact solutions in wheel-rail dynamics analysis.