FMEA - Multiple function failures considerations

[Cephissus]

Ok in this new problem I am having to solve I have the following issue:

Function 1
- Failure 1
Function 2
- Failure 2

Now when assessing the FMEA it is my understanding that we should focus on assessing the failures independently. We should not assess combinations of failures.

However my problem is that I know for a fact these two failures do happen at the same time, and when they do, it is a catastrophe.

Can I represent that in an FMEA framework? Or must I use FTA (fault tree analysis) in this case?

 

[v9991]

Now when assessing the FMEA it is my understanding that we should focus on assessing the failures independently. We should not assess combinations of failures.
However my problem is that I know for a fact these two failures do happen at the same time, and when they do, it is a catastrophe.
Can I represent that in an FMEA framework? Or must I use FTA (fault tree analysis) in this case?

If i get the scenario give by you correctly,
it can be represented as follows.
* for each failure mode, there are multiple affects, i.e., 1->many; and
* for each affect--> many causes( or combinations)

hence above scenario could be covered as follows.
FM - Efect - Cause
fm1 - E1 -r1
- E2-r1+r2
fm2 - E3-r2
E2-r1+r2

 

[Jim Wynne]

Ok in this new problem I am having to solve I have the following issue:

Function 1
- Failure 1
Function 2
- Failure 2

Now when assessing the FMEA it is my understanding that we should focus on assessing the failures independently. We should not assess combinations of failures.

However my problem is that I know for a fact these two failures do happen at the same time, and when they do, it is a catastrophe.

Can I represent that in an FMEA framework? Or must I use FTA (fault tree analysis) in this case?

Process or design FMEA?