Script for Reliability value Column in FMECA

Question

Hi Team

Good Afternoon

I hope this message finds you well. I would like to create a Reliability value column in the FMECA. To add this parameter, I am trying to access the existing Failure Rate (in FIT) parameter (user_failure_rate_in_fit_). However, after adding the script, the system indicates that the parameter does not exist.

If anyone can guide or suggest the correct way to access this variable, I will try to update the script accordingly.

Regards,

Ashok Kumar Modalavalasa

medini_1072807572 · Answer

Hi Marian

Good Afternoon

Thank you for providing the appropriate script for reliability evaluation in the FMECA worksheet

Regards

Ashok Kumar Modalavalasa

medini_1063548292 · Answer

Hi Ashok & others,

I will take the educated guess:

* new derived property to store the reliability of a given FMECA component
* shall take failureRate and the operating time ( priority on the value specified on the component

First remark is that the OCL plugin in medini  does not support the Math library. So OCL or AQL is out of the game JavaScript is the way to go here.
So create a profile property at the FMEA worksheet component entry

and use this JavaScript code snippet as a starting point:/* calculate output based othe operating time ( local /worksheet) and failureRate ( inherited form the sysml model)
*
* self.failureRate => failure rate of the FMEA component ( pointning to a sysml model element 
* self.operatingTime => operatingTime specified at the component ( overiding value at the worksheet)
* self.worksheet.operatingTime => time defined at the worksheet (cover)
*/

/* calculate output based othe operating time ( local /worksheet) and failureRate ( inherited form the sysml model)
*
* self.failureRate => failure rate of the FMEA component ( pointning to a sysml model element 
* self.operatingTime => operatingTime specified at the component ( overiding value at the worksheet)
* self.worksheet.operatingTime => time defined at the worksheet (cover)
*/
//check synch and take the sysml model value if different at component
var fr = self.failureRate != self.element.failureRate ? self.element.failureRate: self.failureRate; 
try {
	Math.exp( -(fr/1e9) * (self.operatingTime == undefined ? self.worksheet.operatingTime : self.operatingTime ));
} catch (e) {
	0;
}

And of course organize the FMEA  table editor to place the column a you like :

Hope this is you wanted to accomplish.

Marian

medini_1072807572 · Answer

Hi Nils

Good Afternoon

I have created a new derived profiling property named Reliability, with the variable name user_reliability.

I am using failureRate as the variable representing the FIT value, and operatingTime as the variable representing the mission time. [The operatingTime value is taken from the FMECA Cover Sheet].

I have written the OCL expression for the reliability calculation using the exponential reliability model (Reliability = exp(−λ × T)), where the FIT value is converted to failures per hour.

The expression I am currently using is:

math::exp(− (self.failureRate / 1e9) * self.operatingTime)

Could you please confirm whether this expression is correct, or advise if any changes are required? Your guidance would be very helpful

Regards,

Ashok Kumar Modalavalasa