Production lot-size model with fuzzy production rate and fuzzy demand rate for deteriorating item under permissible delay in payments

A fuzzy production lot-size inventory model with a permissible delay in payments is developed by assuming that the demand rate and the production rate are triangular fuzzy numbers and the items deteriorate at a constant rate θ. The expressions for the average inventory cost both in the crisp sense and fuzzy sense are derived. The fuzzy model is defuzzified using fuzzy extension principle and its optimization with respect to the decision variables is carried out. The computation procedure is explained with help of a numerical example. Sensitivity of the optimal solution to changes in parameter values is examined.