A Semi-deterministic Wear Model Considering the Effect of Zinc Dialkyl Dithiophosphate Tribofilm

Tribochemistry plays a very important role in the behaviour of systems in tribologically loaded contacts under boundary lubrication conditions. Previous works have mainly reported contact mechanics simulations for capturing the boundary lubrication regime, but the real mechanism in which tribofilms reduce wear is still unclear. In this paper, the wear prediction capabilities of a recently published mechanochemical simulation approach (Ghanbarzadeh et al. in Tribol Int, 2014) are tested. The wear model, which involves a time- and spatially dependent coefficient of wear, was tested for two additive concentrations and three temperatures at different times, and the predictions are validated against experimental results. The experiments were conducted using a mini-traction machine in a sliding/rolling condition, and the spacer layer interferometry method was used to measure the tribofilm thickness. Wear measurements have been taken using a white-light interferometry. Good agreement is seen between simulation and experiment in terms of tribofilm thickness and wear depth predictions

A finite element based technique for simulating sliding wear

ABSTRACT Micro-machines are known to fail prematurely due to excessive wear by virtue of their inherent high operating frequencies and high surface to volume ratio. In order to predict wear and eventually the life-span of such complex systems, several hundreds of thousand operating cycles have to be simulated. Due to the complexity of wear, the existing wear models are insufficient to reliably predict wear based on the material properties and the contact information. As a first step, a technique has been developed which involves post processing of the results from a finite element (FE) contact simulation with a simple wear model to compute wear. The technique can be used to simulate wear in a pin-on-disc set-up in order to improve and verify the wear models

On the local description of wear-induced volume loss and shape changes for engineering surfaces

The paper examines a device-independent representation of wear geometry. Formerly introduced coefficients are generalised according to a local definition. They are then applied to express and predict (employing compatible data-bases) the wear-induced shape changes and related kinematic deviations. First results are presented, from numerical simulations

Wear prediction of ceramic-on-ceramic hip artificial joints

Wear can influence the lifetime and performance of implants and has been found to be a key factor in primary failure of artificial hip joints. The present study aims to present a spatial multibody dynamic model to predict wear in ceramic-on-ceramic hip implants. The problem was formulated by developing a spatial multibody dynamic model of a hip prosthesis taking three-dimensional physiological loading and motion of the human body into account. Then, the Archard wear model was integrated into the dynamic calculation of the hip implant to predict wear. Additionally, geometries of the cup and head were updated throughout the simulation to generate a more realistic wear simulation. The results were validated against current literature. Finally it was illustrated that friction-induced vibration caused excessive wear of hip implant components.Research Excellence Scholarship (iMQRES) - No. 2010017, Portuguese Foundation for the Science and Technology under the research project BIOJOINTS (PTDC/EME-PME/099764/2008)