Introducing variable demand creates problems for my model

Question

question

Ludovic S2 asked Apr 10, '19 Joshua S answered Apr 10, '19

Introducing variable demand creates problems for my model

Hi All,

I am having issues with introducing variation in my basic model. The basic model exists of 10 racks that are subject to a constant demand of around 30 units per time period. Each time one of the racks reaches a inventory level of 1280 units it sends a signal to the source/processor to create a batch of 1260 units. So each rack sends this signal once that inventory level is reached for that rack, and the batch that was triggered by rack 1 needs to end up in rack 1. The batch that is triggered by rack 2 needs to end up in rack 2. And so on.

For a constant demand this works perfectly (see the model without variation). Even when I introduce a normal distribution to the demand (processors behind the racks) it still works perfectly (also see model-without-variation).

The issues are visible once I introduce the poisson distribution (see model-with-variation-in-demand). For whatever reason some of the racks turn out empty and are never replenished. This leaves me with most of my racks completely empty after some run time.

I have no clue why this happens. Is there someone who would be able to help me with this issue ?

Thank you in advance

Kind regards

Ludovic

Software Version:

FlexSim 19.0.2

batch processing reorder point variation

model-with-variation-in-demand.fsm (35.4 KiB)

model-without-variation.fsm (35.1 KiB)

Answer 1 · 2019-04-10T19:37:33Z

Joshua S answered Apr 10, '19

I think what is happening is messages are coming in around the same time and the source/processor can't keep up. I created a simple process flow that creates objects every time a message gets sent to the processor and creates 1260 items in Queue1, so essentially replaces the source and processor3. Take a look at this model and see if it still works how it should.

18457-model-with-variation-in-demand-2.fsm

18457-model-with-variation-in-demand-2.fsm (40.0 KiB)

question