Asian-European Journal of Mathematics Vol. 12, No. 5 (2019) 1950070 (10 pages) c  World Scientific Publishing Company DOI: 10.1142/S1793557119500700 Salvage value and three variable Weibull deteriorating rate for non-instantaneous deteriorating items Hetal Patel ∗,‡ and Ajay Gor † , § ∗ U. V. Patel College of Engineering, Ganpat University Ganpat Vidyanagar-384012, Gujarat, India † Pramukh Swami Science & H. D. Patel Arts College Kadi-382715, Gujarat, India ‡ hetal2K11@gmail.com § ajaygor@yahoo.co.in Communicated by B. K. Dass Received February 11, 2018 Accepted February 17, 2018 Published May 24, 2018 Existing study gives ordering policy for non-instantaneous deteriorating items having three-variable Weibull distribution deterioration rate. Demand rate varies in different time interval. Before deterioration starts, demand is constant and after that it decreases exponentially with respect to time. The study considers total cost function as objective function including salvage value. Shortages are not allowed to stay in time-based compe- tition. Results are proved theoretically and numerically. Sensitivity analysis is performed with respect to salvage value, scale parameter, shape parameter and location parameter including in deterioration rate function to show the liability of the model. Keywords : Non-instantaneous deteriorating item; salvage value; Weibull distribution deterioration rate; economic order quantity (EOQ). AMS Subject Classification: 90B05 1. Introduction Deterioration is generally famous as decay, damage or spoilage. To manage deteri- orating inventory is a very crucial issue. In inventory management, when to order and how much to order are the key questions to solve the economic issue. To do so, economic order quantity (EOQ) models are developed under different criteria. First of all, Ghare and Schrader (1963) developed classical EOQ model under the assumptions of constant demand and constant deterioration rate. Their model is extended by many researchers with different conditions where objective function is profit function or cost function [3, 12, 15]. ‡ Corresponding author. 1950070-1 Asian-European J. Math. 2019.12. Downloaded from www.worldscientific.com by 54.163.42.124 on 07/15/20. Re-use and distribution is strictly not permitted, except for Open Access articles.