Modelling a Construction Process

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Dawr
Posts: 4
Joined: Tuesday 28 October, 2014 - 19:00

Modelling a Construction Process

Post by Dawr »

Hi, I need some hepl with modelling a Construction Prozess.

What I try to do is to make a Model in ED based on construction sequence to optimize the performance time and a number of engaged workers and machinery . For that i work with simple Model of a House which consists of 4 Walls, 1 Door, 2 Plates and 1 Window. I have 3-4 different Products with different Arrival Times (Concrete, formwork and Steel which has to be stored in Queue). On another hand I have 2 Servers (Building workers and machines to accomplish the work). In Addition some Sinks follows (Sink 1 stands for Plate, Sink 2 for Walls, Sink 3 for ceiling....). As you can see the Sink 2 (Walls can only be finished after plate has been done) can oly start after Sink 1 finished. Here is my question is it possible to make this connection between those interdependent Sink?

Hope you understand what i mean :oops:

I would appreciate if you can help me

Best Regards

Dawr
User avatar
HarryBunnik
Posts: 362
Joined: Monday 07 February, 2011 - 11:22

Re: Modelling a Construction Process

Post by HarryBunnik »

Ha Dawr,

You can control to which sink something goes using the SendTo statement. Here you can check how many objects have already entered a sink (see the code below). This tells you if you already have produced enough of a certain construction part:

Code: Select all

Case(
  WhichIsTrue(
    Input(out(1, c)) < 1, {Sink 1, Plate}
    Input(out(2, c)) < 4, {Sink 2, walls}
    Input(out(3, c)) < 1, {Sink 3, ceillings}
    Input(out(4, c)) < 4  {Sink 4, etc.}
  ), 
  1, 
  2, 
  3, 
  4
)
A similar statement you can use to define the cycle time for creating a plate or a wall. Instead of the input of the sinks (the out(#, c)), you have to look at c (the server) itself.

I hope this answers your question and helps you further.

Harry

P.S.

But isn't it an idea to use an assembler instead of a server? That way you can define in the B.O.M. what the requirements are for the construction of each object (columns) and pick then the needed construction materials from the different queues (one for concrete, one for steel and so on), which is indicated on the rows.
Dawr
Posts: 4
Joined: Tuesday 28 October, 2014 - 19:00

Re: Modelling a Construction Process

Post by Dawr »

Hi Harry,

Thank you very much for your quick response, that helps me a lot!

What I know try to do is to find out the start- and endtimes for different alternatives of a certain process and afterwards to write the rusults in excel (for that reason i need to use ActiveX atom i think).

For better understanding of my purpose i attached a model.

The same Problem (but simplified): We have 4 Products (formwork casing, steel, concrete, formwork stripping (could be ignored)) 3 Qeues, Assembler or 3 Servers and 1 Sink for the Walls.
Each of the elements has an effort time=setup time for 1 quantity of a product (hours/amount). Needed Amount of each elements can be found in the modell (see qeues).

To make formwork casing for the walls e.g. it needs 117 hours accordingly to working time of 8hours a day = it takes 15 days, with 3 workers it takes 5 days, with 5 workers it takes 3 days (this are the strategies i need to explain with simulation).

so the effort times= cycle time of each products are (h/amount):
formwork casing: 0,5h = 1800 seconds for 1 amount of a product
steel(reinforcement): 16
concrete: 1,3

The process sequence: steel (reinforcement)-> formwork casing-> concrete must be respected!

I hope you can help me and adjust my model

Regards

Dawr
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HarryBunnik
Posts: 362
Joined: Monday 07 February, 2011 - 11:22

Re: Modelling a Construction Process

Post by HarryBunnik »

Ha Dawr,

If you place an ExcelActiveX atom in your model, you can link it with Excel (also see the help of the ExcelActiveX atom how to do so). Here you can create some tables (using the GUI of the ExcelActiveX). When you open the GUI of such a table, you can create aliases. These are very handy in this case, since they give you the option to write your data to this table and send it to Excel. For instance on the OnExit trigger if one of your servers, you can write the code:

Code: Select all

Cell(Label([ProductNr], i), # {Col nr. depending on where in the model the product is located. },   refExcelActiveX16_table1) := EntryTime(i)
This will write the time the product “i” has spent in the server to table “ExcelActiveX16_Table1”. When you have a separate column per process step in which you’re interested, you can log all the data you need. The row number I would make according to the ProductNr, or another ID with which you can distinguish between different products.

As far as the production times are concerned. You can create a global variable on an initialize atom:

Code: Select all

Dim([valNrWorkers], vbValue, #)
Which you then can use throughout the model to calculate the production times (CylceTime on servers or assemblers and so on).

Code: Select all

Hr(0.5) * valNrWorkers * Cell(1, 1, c) {Reference to the number of objects needed from the B.O.M. as indicated in cell (1,1)}
I hope this gives you some ideas and helps you with your model.

Cheers,

Harry
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