MBSE Reliability Modelling - Roll-up of System Reliability Values

[CMcD]

Hi all,

I am new to the software (using the Corporate trial version) and looking into carrying out some form of reliability analysis
The main concept I hope to accomplish is to develop an architecture model of the diagram that links all components together, with each component represented as a block. Each component would have a reliability value associated with it, and the connections between the blocks would reflect the reliability considerations of the system (series, parallel, redundancy etc.). This would then allow the system to be adjusted (i.e. adding redundancy, changing reliability values), and the changes be reflected in the total “roll-up” reliability values of the total system.

In terms of achieving this, from what I have researched, parametric diagrams seem to be possible. However, I am somewhat confused as to how to achieve this in the EA software. I understand OpenModelica can be used to simulate and provide an output to parametric diagrams. However, I wouldn’t consider the desired output of the system to be a model simulation, but rather just a roll-up of the reliability values that can be automatically updated.

Can this basic roll-up feature of block variables be easily achieved in EA?, and would parametric diagrams and constraints be the right way to do this. Or would OpenModelica have to be used to allow for this total roll-up reliability value to be updated as the model changes?.

Thanks

[Uffe]

Hello,


There is an OpenModelica integration that seems to be relevant to your need, though I haven't tried it myself so I can't say whether it can do the roll-up thing you're after.

It's been around for a few years and this is the first time I can recall anyone mentioning it on the forum. Knowing EA this probably means that it works OK for a trivial demo, but once you get into anything more complex it will not work and it won't tell you why.
The fact that the manual page references OpenModelica 1.9.2 is not a good sign, and the fact that the EA edition comparison chart lists it as being introduced in v14 while the manual for it goes as far back as v13.0 is worrying too.

But it's probably worth an hour's fiddling to see if you can get it to work.

HTH,


/Uffe

[CMcD]

Hi Uffe,

Thanks for the reply, I have experimented somewhat with OpenModelica and have got it to facilitate the roll-up functionality - albeit in a quite rudimentary form.

The main aspect I am trying to model is having a chain of system components (say an instrument that is connected to a control board by a series of interfaces and electrical connections as you can see in the picture), and having redundant aspects within the functional chain such that cross-strapping can be achieved.

<img src="https://i.ibb.co/6XkD83g/Architecture.png" alt="Architecture" border="0">
<img src="https://i.ibb.co/BBRy8Rv/Constraints.png" alt="Constraints" border="0">

Essentially, by adding in varying levels of cross-strapping (i.e. varying which components have redundancy), the overall reliably of the system would be effected.

However, the legwork taken to structure the Parametric diagrams and then relying on OpenModelica to carry out what is very basic addition and multiplication seems to be very high (see in the pictures). I am also completely stumped as to how I would implement the ability to adapt the architectural model of the system, and get that to relate to affecting parametric model and change the total reliability value produced as all the constraint equations are static, and I don’t see a way to allow them to adapt, say as more elements are added to the architectural model.

<img src="https://i.ibb.co/TLBPttQ/Par1.png" alt="Par1" border="0">
<img src="https://i.ibb.co/XYTBRf1/Par2.png" alt="Par2" border="0">

Consequently, I am struggling to see an advantage in this application for using a SysML tool over a static Visio diagram and Excel spreadsheet as I can't seem to extract the beneficial interconnection of aspects of a system model

I want to ask if it seems like I am failing to implement the software correctly, or if this type of task is not practical within the SysML environment of EA.

Thanks