Multi-criteria Analysis of Internal Cross-docking Operations

The performance of internal material handling operations in an existing cross-docking facility is sought to be improved from both a logistic and environmental perspective. The facility studied consists of a transportation terminal serving a vast less-than-truckload (LTL) chain. Inside the cross-dock, all material handling is performed by forklifts fuelled by compressed natural gas (CNG). A review of the state of the art is conducted, from which a cross-dock characterization approach is outlined. Similarly, the literature reveals that discrete-event simulation, while generally under-looked, is an appropriate tool for the study of such transportation facilities. Accordingly, an agent-based simulation (ABM) model is developed in order to study the cross-dock. The model is influenced by existing warehousing models, as well as by traditional discrete-event modelling in an industrial setting. Moreover, a comprehensive analysis of the current state of operations was completed in order to define model boundaries, inputs and agent interactions. Then, the model was used to conduct experiments based on distinct door-assignment strategies, having CNG consumption and forklift distance as response variables. The generation of door assignments, conversely, was achieved by a heuristic based on the minimum distance between dock doors and pallet flow. The experimental results indicate that such door assignments do lead to a reduction in both response variables. Further study is, howbeit, required to assess the full impact of door assignments in the system, beyond internal boundaries.