The use of Analytical Hierarchy Process (AHP) decision model for materials and assembly method selection during railcar development

The need for improved performance, operational efficiency as well as cost and environmental sustainability necessitate the selection of appropriate materials and assembly methods during railcar manufacturing and maintenance. The selection of the most appropriate materials and assembly methods amidst different materials is a Multi-Criteria Decision (MCD) which requires a scientific decision support framework. In this study, a model based on the Analytical Hierarchy Process (AHP) was used for the selection of the most suitable material and method of assembly for the development and maintenance of the body shell of a railcar. The performance of stainless steel, aluminum and carbon steel as well as welding methods such as Laser Arc Welding (LAW), Friction Stir Welding (FSW) and Metal Inert Gas (MIG) and the Resistance Spot Welding (RSW) currently used in railcar development were examined. The strength to weight ratio, crash worthiness, mechanical properties, degree of formability as well as cost effectiveness, end of life, and functional requirements were the key decision variables that form the criteria, which were broken down into a number of sub-criteria. The criteria and sub-criteria were pairwise compared to determine their priorities to the design and service requirements (goal). The AHP gave a detailed analysis of the materials as well as the methods of assembly that meet the service requirements of the railcar in a hierarchical order. Hence, this work provides the application of decision support framework for meeting the increasing design and service requirements in the railcar manufacturing industries.