Intermodal terminal cargo handling simulation using Petri nets with predicates

Abstract

This article describes the modelling of a container terminal using Petri nets with predicates. It starts by describing this extension of the basic Petri net theory and demonstrates its applicability and adequacy to solving complex logistic processes and reliability problems more intuitively and easily than the basic Petri net theory. The developed computational model allows the evaluation of different configurations and combinations of transport equipment, providing a very complete port system’s simulation. Such simulation, based on an estimated container flow, allows the calculation of several waiting times, time in port, attendant time, queuing time, equipment and resource occupation and so on. Changing the internal configuration of the terminal or the external conditions will result in different costs and profits to the terminal, making it possible to perform a terminal optimization based on the study of long-term performance indicators under different conditions. This systematic approach is implemented in a specific case study related to the operational cargo handling procedures of a container terminal. The study will be made considering verified operation performance over some months where the mean values of the variables considered are representative of the ‘typical’ operation of that particular terminal, which allows a validation of the model.