How to model a Brakdown given the probability of failure and the time to repair

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Cheikh Ahmed V asked Nov 8, '20 Cheikh Ahmed V answered Nov 9, '20

How to model a Brakdown given the probability of failure and the time to repair

Hello FlexSim Community;

I am trying to model a brakedown of a processor in FlexSim, however the informations that i have are the time to repair and the probability of failure.

Inside FlexSim they ask mainly the following inputs:

a) "Down time" which is the mean time to repair.

b) "First Failure time" which is not given in our case instead they gave the probability of failure and my Question is : what is the relation between the two parameters? And if there is a way to model the brakedown using the probability of failure?

Thanks in advance.

Software Version:

FlexSim 20.0.8

flexsim 20.0.8 brakedown probability of failure

failure.png (29.3 KiB)

Answer 1 · 2020-11-09T11:11:01Z

Cheikh Ahmed V answered Nov 9, '20

Thank you very much for your answers they really helped me

Answer 2 · 2020-11-09T10:47:17Z

Clair A answered Nov 9, '20 Clair A edited Nov 9, '20

Hello @Cheikh Ahmed V,

If you have no information about the First Failure Time, I suggest you set it equal to the Up Time.

Quick reminder about the breakdown parameters in FlexSim:

If you set the First Failure Time equal to the Up Time, then the average percentage in breakdown is:

100 x (Down Time) / (Down Time + Up Time)

In your case, you know the down time and the percentage of breakdown, so you can easily calculate the up time.

mtbf-mttr.png (164.4 KiB)

Answer 3 · 2020-11-09T10:44:14Z

Joerg Vogel answered Nov 9, '20

MTBF MTTR in manual

A probability is not directly a statistical distribution.

You can try bernoulli or

3600 + uniform(-300,300,3)

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