Vibrations and impact loads are common sources of mechanical damage in transportation applications; however, their impacts on polymer electrolyte membrane fuel cells (PEMFCs) have yet to be fully investigated. In this work, the damage propagation in the membrane electrode assembly (MEA) is investigated under vibration conditions with a focus placed on the interface between the membrane and catalyst layer at the cathode. A numerical model based on the cohesive element approach is developed, and a parametric study is performed to investigate the effects of amplitude and frequency of applied vibrations as well as initial delamination length on damage propagation. Non-linear relationships were found between the damage propagation and these parameters, with the frequency of vibration having the dominant effect on damage propagation at larger amplitudes. This work provides insight into the importance of considering mechanical damage to the MEA under vibration conditions in transportation applications. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.