Het ontwerp van een generiek simulatiemodel voor een reservedelenhuishouding.
Report 93.3.LT.4298, Transport Technology, Logistic Engineering.
At the Royal Dutch Navy sparepart stock, a distinction is made between
stocks on board and stocks ashore. In these stocks there are two types of
spare parts: repairables and consumables. The repairable items make a
circular course through the inventory system.
Usualy two analytical models are used to define the stocklevels ashore and
on board. The performance indicator for the stocks ashore is the service level,
while the availability of the installations for which the stocks are held
indicates the performance of the on-board-stocks. An integral view over
both stocks could bring the performance of the total stock to a higher
It appears that the the situation at the Navy is not unique.
Because of this, the idea of a model that can evaluate situations
equivalent of the sitation at the Navy becomes attractive. In this model
the processes at the installations and the processes in the inventory
system should be separated. A new situation arises from this separation in
which service units replace the onbourd stocks. These service units are
able to give service on serveral locations. With a small stock they travel
from site to site to replace parts that have failed. Every service unit
has its own service area. An example for such a situation is a company
that takes care of maintenance of copiers. The service units depend on a
central depot for their supply.
It is hard to find an analytical solution for the integral view. Therefore a
simulation model is made. The goal of this model is to evaluate propositions
for the stocklevels at the service units and the central depot wich are
generated by separate analytical models. Besides that, experiments can be done
with stocklevels, failure rates and the repair process of the broken parts.
The first step of the design of the simulation model leads to a
conceptual model. This model bases the object oriented design of the
simulation model. This model is implemented into FEL-GLOW, a model which
generates the stocklevel propositions for the Royal Dutch Navy. The most
important conclusion of the experiments with stock levels, is that the
stock should be concentrated at the service units. High performance of the
central depot is not necessary. Besides that, reduction of the
repair time at the repair depot will cause reduction of the amount of parts
needed in stock.
Reports on Logistic Engineering (in Dutch)
, TU Delft