Critical Path Method with Fuzzy Activity Times

Abstract

The Critical Path Method (CPM) is very useful in planning and controlling complex projects when their activity times are known precisely. However, in real-life applications, the durations are foreseen in the planning phase of the project; when it is put into practice, it may vary due to various reasons such as machine breakdowns, human factors, and disruptions in material supply. Accordingly, due to the uncertainty and difficulties in estimating operating times, CPM may not be able to accurately and fully represent real projects. From this point of view, in this study, it is aimed to perform critical path analysis in a project network whose activity durations consist of triangular fuzzy numbers. In the first stage, critical path analysis and project completion time were found by using possible, optimistic and pessimistic values. Then, Yager’s ranking method was used to ranking the fuzzy numbers and the project completion time and critical path were calculated with the crisp values obtained. The results were evaluated by comparing and the importance of using fuzzy numbers instead of crisp numbers in the CPM method was revealed.