Inventory policies for seasonal items with logistic-growth demand rate under fully permissible delay in payment: a neutrosophic optimization approach

Abstract

The present study investigates an inventory system for seasonal products under variable demand rate and partial backordering in a competitive market. Among various demand rate functions used in the existing literature of economic order quantity (EOQ) models, the logistic-growth function is best known to estimate market already captured and fraction of market remaining to be captured by new seasonal and technology driven items. Weibull distribution well represents the seasonality and versatility of these products. Due to retailers’ reluctance to purchase and store these perishable products, supplier offers the delay in payment. In view of the above, the proposed EOQ model suitable for those items considers the logistic-growth demand rate, Weibull distribution deterioration rate and partial backordering along with fully permissible delay in payment. Since the neutrosophic set quantifies the imprecise information in real-life scenarios, the proposed EOQ model is optimized in neutrosophic environment. A general unconstrained nonlinear mathematical model with neutrosophic coefficients is optimized using the weighted arithmetic mean function, subject to specified neutrosophic norm. A special case with the neutrosophic conjunction norm along with four lemmata is considered to minimize the cost functions with neutrosophic coefficients to proposed EOQ model across various trade-credit intervals. Here, the managerial insights identified through sensitivity analysis advocate to reduce the expenses on early promotions for foreshortening the demand at the beginning of cycle. Also, the present study demonstrates the optimal inventory depletion time to depend on the demand during the shortages in neutrosophic environment.