Natural fibre composite selection for two-stroke marine engine under-piston door using hybrid AHP and TOPSIS methods

Abstract

This article presents the selection process of natural fibre composites (NFC) material for the application of a two-stroke marine engine under-piston door (UPD) utilising a combination of the Analytical Hierarchy Process (AHP) with the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). NFC consists primarily of a biopolymer enforced with natural fibres. The selection of the best biopolymer and natural fibre was based upon key parameters, which represented the selection criteria. Natural fibre was selected based on four criteria; density, Tensile Strength (TS), Young's modulus (YM) and price. Biopolymer was selected based on an additional two criteria; flammability and melting point. A pairwise comparison was made for each criterion, establishing a matrix for the determination of the weightage using the AHP. This weightage was then applied into the TOPSIS method for the final ranking of natural fibre and biopolymer candidates. With a score of 0.870 in relative closeness to ideal solution, flax was determined to be the best natural fibre. Poly (lactic acid) obtained a score of 0.801 as the best biopolymer. Through this article, a synergy between AHP and TOPSIS methods were demonstrated in the selection and ranking of natural fibre and biopolymer as constituents of NFC for the potential application as alternative material for marine machinery application.