Vehicle Routing Problem with time windows under availability constraints

Disruption Management is an emerging field, where operational research techniques are used to deal with delays in many environments. Yu Gang defines the concept of Disruption Management as "in the beginning of an economic cycle an optimal or quasi-optimal plan is obtained by the use of some optimization models. When an original planning is executed, disruptions, which are caused by several internal or external factors, may occur from time to time. As a result, the original planning cannot remain optimal or even Feasible. For this reason, we need to prepare a new revised plan reflecting the constraints and objectives of the evolved environment while minimizing the negative impact of disruption." In this work we present a rescheduling model based on Variable Neighborhood Search methaheuristic for the vehicles routing problem with time windows when one or more vehicles require preventive maintenance activities after the supply of a set of customers.