A model for particle fatigue due to impact loads

The wide use of particulate materials in industry has elicited various problems that are related to particle size variations (increase or decrease) in diverse mechanical processes. One of the main problems is the low accuracy of designing size reduction systems. The particles break as a result of continuous loads higher than their strength. The particles may also break due to repeated loads lower than their strength (a phenomenon related to fatigue). Therefore, a characterization of particle strength with static and repeated loads is crucial. The current work introduces and validates the fatigue model which development is based on the theoretical model. The modified model enables us to calculate particle strength decreases with every additional loading event. The model depends on six empirical and material related parameters, and was validated by appropriate experiments with a variety of NaCl particle sizes. Since the fatigue effect among particulate materials is a very common event, this study may enable the simulating comminution processes with higher accuracy.

This work presents development and validation of the semi-theoretical fatigue model. The proposed model is suitable to predict particle strength fatigue in systems with inconstant impact velocities between the loads. The figure demonstrates that most of the results are predicted with satisfying accuracy, which is reasonable considering the comprehensiveness of the model and the complexity of the measurement.Figure optionsDownload as PowerPoint slideHighlights
► Description of the test procedure for the multi load comminution systems
► Introduction of a semi theoretical model which describes fatigue phenomenon
► Development of fatigue model for systems with inconstant load amplitude
► Investigation of the model parameters in sake of model generality
► Model validation with the experimental data of NaCl particles