A Comparative Study for Fuzzy Ranking Methods in Determining Economic Life of Equipment

摘要

Replacing the equipment at it's economic life reducing the direct cost of construction projects, which leads to increasing the probability of winning bids. This problem involves capital cost, scrap value, maintenance cost, and rate of interest. The main aim of this paper is to study the effect of fuzzy ranking method based on centroid indices in determining replacement time (economic life) of equipment. Normal trapezoidal fuzzy numbers were used for their simplicity and for the comparison of different ranking methods. The time value of money was considered. Nine ranking methods were considered. Two examples were conducted to demonstrate the effect of fuzzy ranking method on economic life of equipment. The main contribution of this research is that five methods give the same results for~( )the~( )economic life for fuzzy replacement problem which are consistent with human intuition. These methods are: Cheng [1], Chu and Taso [2], Wang et al. [3], Dat et al. [4] and Gani and Mohamed [5]. On the other hand, Chen and Chen [6] and Allahviranloo and Saneifard [7] ranking methods give another replacement time which is also consistent with human intuition. Yager [8] and Chen and Chen [9] ranking methods give different results for replacement time which are not consistent with human intuition.