A production inventory model for non-instantaneous deteriorating items with two-phase production period, stock-dependent demand and shortages

In this paper, a production inventory model for non-instantaneous deteriorating items with two-phase production periods are developed. The production rates of the two different production periods differ while the demand within such periods are the same and constant. Also, the demand within the demanding period before deterioration starts is assumed to be stock-dependent while that of within deterioration and shortage periods are constant. Shortages are allowed and completely backlogged. A theorem and lemmas were framed to characterise the optimality of the model developed and a numerical experiment is conducted to show the applicability of the model. Finally, sensitivity analysis is carried out to demonstrate the effects of change of some system parameters on the optimal solutions obtained during the numerical experiment and some suggestions and recommendations are presented based on the results obtained.