Review Article Application and comparative study of new optimization method for performance ranking of friction materials Vishal Mahale 1 , Jayashree Bijwe 1 and Sujeet Sinha 2 Abstract Good friction materials should satisfy diverse and contradictory performance requirements such as adequate friction (m & 0.35–0.45), resistance to wear, fade, squeal, judder, etc. in consort with good recovery and less noise producing tendency. To achieve center point of all these conflicting criteria and selection of best overall performing friction material is multiple criteria decision making (MCDM) problem and very difficult task. Decision maker can easily make decision with single criteria without the help of any optimization tool by maximizing beneficial criteria and minimizing non- beneficial criteria. However, it is extremely challenging task if decision making involves several number of conflicting criteria. Few techniques are reported in the literature such as ‘multiple criteria decision model’, ‘Multi-attribute decision model’, ‘extension evaluation method’ (EEM), etc. for performance ranking of friction materials. However, the simplicity, reliability, applicability, time devoted for the analysis, etc. are always most important aspects of selecting a right tool for the analysis. In this paper application of a technique ‘multiple objective optimization on the basis of ratio analysis’ (MOORA) has been first time employed for performance ranking of friction materials. A comparative study of MOORA and currently used methods MCDM and EEM are also presented. MOORA proved to be the best tool based on the criteria such as simple to use, fast, flexible, and efficient one. Keywords Multiple criteria decision model, extension evaluation method, multiple objective optimization on the basis of ratio analysis, friction materials Date received: 11 September 2016; accepted: 4 April 2017 Introduction The non-asbestos organic (NAO) brake friction materials (FMs) extensively used today are multi- ingredient polymer matrix composite with complex formulations, which are generally developed through trial and error, combined with prior experience of manufacturers. Approximately 10–25 ingredients are generally used in commercial FMs to accomplish the diverse and contradictory performance requirements such as adequate friction (m & 0.35–0.45), resistance to wear, fade, squeal, judder, etc. in consort with good recovery and less noise producing tendency, etc. 1,2 The development of FM composites is a com- plex task. The complete standardized procedure for the development of FM composites is discussed elsewhere in the literature. 3–6 In our daily lives or in professional environment, there are typically multiple conflicting criteria that need to be evaluated by making decisions. Traditional single criteria decision making is a simple task based on the fact of maxi- mization of beneficial criteria with minimization of non-beneficial criteria. Decision maker can easily make decision with single criteria without help of any optimization tool. However, it is difficult if deci- sion making involves several number of conflicting criteria. Multi-criteria decision making (MCDM) is a major and well-known branch of decision making. MCDM deals with the decision making on the basis of several number of criteria. The ranking of the available brake pad composite alternatives on the basis of several number of conflict- ing criteria is a complex task. Hence performance 1 Industrial Tribology, Machine Dynamics and Maintenance Engineering Centre, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India 2 Department of Mechanical Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India Corresponding author: Jayashree Bijwe, Industrial Tribology, Machine Dynamics and Maintenance Engineering Centre, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India. Email: jbijwe@gmail.com Proc IMechE Part J: J Engineering Tribology 0(0) 1–12 ! IMechE 2017 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/1350650117708479 journals.sagepub.com/home/pij