Impact of Design Methods and Maintenance Policies on the Dynamic Behaviour of Escalators

Throughout their service life, escalators undergo wear and tear that disrupt their dynamic behaviour and lead to faster deterioration or collision between components. Therefore, balancing the dynamic behaviour of escalators is one of the keys to longer life expectancy and safety. This requires thorough adjustments and regular part replacements. This paper assesses the impacts of internal and external parameters on the dynamic behaviour of escalators in order to enhance maintenance policies and design methods. Given the wide range of maintenance, design and environmental variables, this paper solely focuses on studying the most common parameters, the step chain lubrication and tension, the step design, the guide rail lubrication and the number of passengers carried on each step. For this purpose, a model is created using a multi-body dynamics’ (MBD) system. Conducting Taguchi-designed experiments, the main effects of these factors and their interactions on the stress distribution and displacement of each moving parts of the model are studied. The results are then compared using ANOVA to determine the significant effects for each response. Heavy passenger flows greatly alter force distribution throughout the system, leading to reduced fatigue life of the steps, rollers and guide rails. Poor step chain lubrication and a maladjusted tensioning station have a significant impact on the step chain tension, yielding a higher collision risk between the steps and the combplates. Guide rail lubrication does not seem to significantly affect the system dynamics. No significant interaction between the studied parameters has been found and the responses are for the most part linear. This study showcases the major impact of passenger flows on the stresses applied on the moving parts and calls for an improved assessment of effective passenger flows in the dimensioning of escalators.