JJPEngr
June 3rd, 2008, 09:59 AM
We have recently encountered multiple failure modes in two analysis cases and available articles on weibull.com or online help do not address what we need to do.
1. in ALTA 7 Pro, a set of data has two failure modes. How do we use Weibull++7 to do a mixed Weibull and then go back to ALTA Pro to plot separate life stress relationships for each sub population?
The particular data set has 13 samples, three stresses (voltage, load current, and duty cycle) with 2 failures of one mode and 5 failures of a different mode.
2. In a set of field data with a large population (several thousand samples and mostly suspensions) over a year and a half, Weibull++7 with a mixed Weibull shows 2 clear subpopulations with betas of about 0.7 and 2.0. We know of at least three predominant failure modes. Is there a way to specify subpopulations in Weibull++ 7 rather than just let the tool select them? With such a large population, is there an easy way to separate out subpopulations with each of the predominant failure modes for separate analysis?
Thank you
1. in ALTA 7 Pro, a set of data has two failure modes. How do we use Weibull++7 to do a mixed Weibull and then go back to ALTA Pro to plot separate life stress relationships for each sub population?
The particular data set has 13 samples, three stresses (voltage, load current, and duty cycle) with 2 failures of one mode and 5 failures of a different mode.
2. In a set of field data with a large population (several thousand samples and mostly suspensions) over a year and a half, Weibull++7 with a mixed Weibull shows 2 clear subpopulations with betas of about 0.7 and 2.0. We know of at least three predominant failure modes. Is there a way to specify subpopulations in Weibull++ 7 rather than just let the tool select them? With such a large population, is there an easy way to separate out subpopulations with each of the predominant failure modes for separate analysis?
Thank you