Template:Weibull++ SimuMatic Example - Revision history

Harry Guo at 18:12, 7 March 2012

2012-03-07T18:12:06Z

← Older revision		Revision as of 18:12, 7 March 2012
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	'''Step 5:''' Increase sample size and calculate the confidence bound ratio until find an appropriate sample size. When the sample size is 18, the calculated bound ratio is 1.502. The results are:		'''Step 5:''' Increase sample size and calculate the confidence bound ratio until find an appropriate sample size. When the sample size is 18, the calculated bound ratio is 1.502. The results are:

	[[SimuMatic Setup Sorted 10 sample size 18.png\|thumb\|center\|400px]]		[[image: SimuMatic Setup Sorted 10 sample size 18.png\|thumb\|center\|400px]]

	[[image: SimuMatic Setup Sorted 90 sample size 18.png\|thumb\|center\|400px]]		[[image: SimuMatic Setup Sorted 90 sample size 18.png\|thumb\|center\|400px]]

Harry Guo at 18:07, 7 March 2012

2012-03-07T18:07:36Z

← Older revision		Revision as of 18:07, 7 March 2012
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	Click on Update, the solved parameters become the inputs for the SimuMatic:		Click on Update, the solved parameters become the inputs for the SimuMatic:
	~~[[image: Select SimuMatic.png\|thumb\|center\|400px]]~~


	[[image: SimuMatic Setup Distribution updated.png\|thumb\|center\|400px]]		[[image: SimuMatic Setup Distribution updated.png\|thumb\|center\|400px]]

Harry Guo at 18:06, 7 March 2012

2012-03-07T18:06:51Z

← Older revision		Revision as of 18:06, 7 March 2012
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	'''Step 2:''' In order to simulate random data, a distribution must be assumed. This is set in the following window.		'''Step 2:''' In order to simulate random data, a distribution must be assumed. This is set in the following window.

	[[image: SimuMatic Setup ~~Parameter Estimator~~.png\|thumb\|center\|400px]]		[[image: SimuMatic Setup Distribution.png\|thumb\|center\|400px]]

	The engineer knows that by time 200, probably 1 out of 100 test units will fail; by time 300, probably 4 out of 100 test units will fail. Based on this information, the '''Quick Parameter Estimator''' can generate the parameters for a specified distribution.		The engineer knows that by time 200, probably 1 out of 100 test units will fail; by time 300, probably 4 out of 100 test units will fail. Based on this information, the '''Quick Parameter Estimator''' can generate the parameters for a specified distribution.

Harry Guo at 18:05, 7 March 2012

2012-03-07T18:05:31Z

← Older revision		Revision as of 18:05, 7 March 2012
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	[[image: SimuMatic Setup Distribution updated.png\|thumb\|center\|400px]]		[[image: SimuMatic Setup Distribution updated.png\|thumb\|center\|400px]]

	Step 3: Set up the rest inputs for SimuMatic using the following settings.		'''Step 3:''' Set up the rest inputs for SimuMatic using the following settings.

	[[image: SimuMatic Setup censoring.png\|thumb\|center\|400px]]		[[image: SimuMatic Setup censoring.png\|thumb\|center\|400px]]

Harry Guo: Created page with ''''Example of Using Weibull++ SimuMatic ''' SimuMatic is a simulation tool in Weibull++. It can be used to design life tests, reliability demonstration tests, and study the effe…'

2012-03-07T18:05:09Z

Created page with ''''Example of Using Weibull++ SimuMatic ''' SimuMatic is a simulation tool in Weibull++. It can be used to design life tests, reliability demonstration tests, and study the effe…'

New page

'''Example of Using Weibull++ SimuMatic '''

SimuMatic is a simulation tool in Weibull++. It can be used to design life tests, reliability demonstration tests, and study the effect of sample size.

Assume an engineer wants to design a test to estimate the B10 life a product. He knows large test sample size will provide more confidence on the analysis results from the test outcome. In other words, large sample size will narrow the confidence interval of the estimated B10 life. If he wants the ratio of the estimated one-sided upper and lower confidence bounds at a confidence level of 90% to be less than 1.5, how many samples he need to test?

The needed sample size can be found using '''SimuMatic''' in Weibull++.

'''Step 1:''' To use Simumatic, select '''Add Weibull++ SimuMatic''' from the '''Tools''' from the '''Project Explore'''.

[[image: Select SimuMatic.png|thumb|center|400px]]

'''Step 2:''' In order to simulate random data, a distribution must be assumed. This is set in the following window.

[[image: SimuMatic Setup Parameter Estimator.png|thumb|center|400px]]

The engineer knows that by time 200, probably 1 out of 100 test units will fail; by time 300, probably 4 out of 100 test units will fail. Based on this information, the '''Quick Parameter Estimator''' can generate the parameters for a specified distribution.

Click on the '''Quick Parameter Estimator''', enter the above information, and calculated the distribution parameters. The result is given at:

[[image: SimuMatic Setup Parameter Estimator.png|thumb|center|400px]]

Click on Update, the solved parameters become the inputs for the SimuMatic:
[[image: Select SimuMatic.png|thumb|center|400px]]

[[image: SimuMatic Setup Distribution updated.png|thumb|center|400px]]

Step 3: Set up the rest inputs for SimuMatic using the following settings.

[[image: SimuMatic Setup censoring.png|thumb|center|400px]]

[[image: SimuMatic Setup Number of points.png|thumb|center|400px]]

Initially, we used 5 as the initial guess for the sample size. This value should be adjusted based on calculated confidence bound ratio. If the ratio is bigger than the required value of 1.5, we should increase it; if the ratio is smaller than the required value of 1.5, we should decrease it. By trial and error, we can find the most appropriate value for sample size.

[[image: SimuMatic Setup Analysis.png|thumb|center|400px]]

[[image: SimuMatic Setup Test Design.png|thumb|center|400px]]

[[image: SimuMatic Setup Reliability and Times.png|thumb|center|400px]]

In the above figure, we set Reliability value = 0.9 because we need to estimate the B10 life of the product.

'''Step 4:''' Click on '''Generate''' to generate the data and review the results. Two sheets were generated for the results. In the '''Simulation''' Sheet, the estimated results for each generated data set were given. In the '''Sorted''' sheet, results are sorted. It is shown below.

[[image: SimuMatic Setup Sorted 10.png|thumb|center|400px]]

In above figure, the 10% percentile of the calculated B10 life (Reliability = 0.9). From the above result, we can see the lower bound of the B10 life is 289.41. Similarly, we can find the upper bound to be:

[[image: SimuMatic Setup Sorted 90.png|thumb|center|400px]]

The ratio of these two bounds is 598.31/289.41 = 2.07, which is bigger than the required value of 1.5. Therefore, we need to increase the sample size. The simulation result and the confidence bounds are also can be viewed at the following plot.

[[image: SimuMatic First Plot.png|thumb|center|400px]]

'''Step 5:''' Increase sample size and calculate the confidence bound ratio until find an appropriate sample size. When the sample size is 18, the calculated bound ratio is 1.502. The results are:

[[SimuMatic Setup Sorted 10 sample size 18.png|thumb|center|400px]]

[[image: SimuMatic Setup Sorted 90 sample size 18.png|thumb|center|400px]]

The plot is:

[[image: SimuMatic Second Plot sample size 18.png|thumb|center|400px]]

Compare this figure with the plot for sample size of 5, it can be seen that the confidence interval is much narrow.

Therefore, using SimuMatic we found the suitable sample size of 18.
There are many other results in SimuMatic. Click on the ''''Summary…''' button, you can view the summary.
[[image: SimuMatic Summary.png|thumb|center|400px]]