Paper Clip Example - Revision history

Richard House at 07:40, 7 August 2012

2012-08-07T07:40:13Z

← Older revision		Revision as of 07:40, 7 August 2012
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	Note that the paper clips used in this example are Jumbo paper clips that are capable of repeated bending. Different paper clips will yield different results. Additionally, and so that no other stresses are imposed, take caution to assure that the rate at which the paper clips are cycled remains the same across the experiment.		Note that the paper clips used in this example are Jumbo paper clips that are capable of repeated bending. Different paper clips will yield different results. Additionally, and so that no other stresses are imposed, take caution to assure that the rate at which the paper clips are cycled remains the same across the experiment.


	'''Paper Clip Test'''		'''Paper Clip Test'''
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	3) Repeat steps 1 and 2 until the paper clip breaks. Count and record the cycles-to-failure for each clip.		3) Repeat steps 1 and 2 until the paper clip breaks. Count and record the cycles-to-failure for each clip.


	'''Analysis'''		'''Analysis'''

	In this experiment, a sample of six paper clips were tested to failure at both 90º and 180º bends. A base test sample of six paper clips was tested at a 45º bend (the assumed use stress level) to confirm the analysis. The cycles-to-failure are given next.		In this experiment, a sample of six paper clips were tested to failure at both 90º and 180º bends. A base test sample of six paper clips was tested at a 45º bend (the assumed use stress level) to confirm the analysis. The cycles-to-failure are given next.


	<div style="text-align: center;"> '''Cycles-to-Failure at 90º [[File:90degree.gif]] </div>		<div style="text-align: center;"> '''Cycles-to-Failure at 90º [[File:90degree.gif]] </div>
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	[[Image:degreesbend.png\|center\|600px\|ALTA Standard Folio.]]		[[Image:degreesbend.png\|center\|600px\|ALTA Standard Folio.]]
	~~<br>~~
	~~<br>~~
	[[Image:probweib.png\|center\|600px\|Lognormal Probability Plot of both Stress Levels.]]		[[Image:probweib.png\|center\|600px\|Lognormal Probability Plot of both Stress Levels.]]
	~~<br>~~
	~~<br>~~
	[[Image:accvsstress.png\|center\|600px\|Acceleration Factor vs. Stress plot.]]		[[Image:accvsstress.png\|center\|600px\|Acceleration Factor vs. Stress plot.]]

	~~<br>~~
	The MTTF at 45º is estimated to be 71.375467 cycles, as shown next.		The MTTF at 45º is estimated to be 71.375467 cycles, as shown next.

	~~<br>~~
	[[Image:Ch12-Ex1-4.png\|center\|550px\|Mean Life at 45º Bend.]]		[[Image:Ch12-Ex1-4.png\|center\|550px\|Mean Life at 45º Bend.]]


	The next two figures show the analysis of the base data in Weibull++ and the base MTTF estimate. In this case, our accelerated test correctly predicted the MTTF as verified by our base test.		The next two figures show the analysis of the base data in Weibull++ and the base MTTF estimate. In this case, our accelerated test correctly predicted the MTTF as verified by our base test.

	~~<br>~~
	[[Image:ALTA14.5b.gif\|center\|600px\|Base 45º Data Lognormal Probability Plot.]]		[[Image:ALTA14.5b.gif\|center\|600px\|Base 45º Data Lognormal Probability Plot.]]


	[[Image:ALTA14.5.gif\|center\|550px\|Mean Life of Base Test.]]		[[Image:ALTA14.5.gif\|center\|550px\|Mean Life of Base Test.]]

Richard House at 07:57, 3 August 2012

2012-08-03T07:57:19Z

← Older revision		Revision as of 07:57, 3 August 2012
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	<br>		<br>
	[[Image:Ch12-Ex1-4.png\|center\|~~600px~~\|Mean Life at 45º Bend.]]		[[Image:Ch12-Ex1-4.png\|center\|550px\|Mean Life at 45º Bend.]]


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	[[Image:ALTA14.5.gif\|center\|~~600px~~\|Mean Life of Base Test.]]		[[Image:ALTA14.5.gif\|center\|550px\|Mean Life of Base Test.]]

Richard House at 07:56, 3 August 2012

2012-08-03T07:56:36Z

← Older revision		Revision as of 07:56, 3 August 2012
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	Enter the data in an ALTA standard folio, and analyze the results assuming a lognormal life distribution (fatigue) and an inverse power law relationship (non-thermal) for the life-stress model. The following figures show the analysis and some of the results.		Enter the data in an ALTA standard folio, and analyze the results assuming a lognormal life distribution (fatigue) and an inverse power law relationship (non-thermal) for the life-stress model. The following figures show the analysis and some of the results.

	[[Image:degreesbend.png\|center\|~~500px~~\|ALTA Standard Folio.]]		[[Image:degreesbend.png\|center\|600px\|ALTA Standard Folio.]]
	<br>		<br>
	<br>		<br>
	[[Image:probweib.png\|center\|~~500px~~\|Lognormal Probability Plot of both Stress Levels.]]		[[Image:probweib.png\|center\|600px\|Lognormal Probability Plot of both Stress Levels.]]
	<br>		<br>
	<br>		<br>
	[[Image:accvsstress.png\|center\|~~500px~~\|Acceleration Factor vs. Stress plot.]]		[[Image:accvsstress.png\|center\|600px\|Acceleration Factor vs. Stress plot.]]

	<br>		<br>
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	<br>		<br>
	[[Image:Ch12-Ex1-4.png\|center\|~~500px~~\|Mean Life at 45º Bend.]]		[[Image:Ch12-Ex1-4.png\|center\|600px\|Mean Life at 45º Bend.]]


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	<br>		<br>
	[[Image:ALTA14.5b.gif\|center\|~~500px~~\|Base 45º Data Lognormal Probability Plot.]]		[[Image:ALTA14.5b.gif\|center\|600px\|Base 45º Data Lognormal Probability Plot.]]


	[[Image:ALTA14.5.gif\|center\|~~500px~~\|Mean Life of Base Test.]]		[[Image:ALTA14.5.gif\|center\|600px\|Mean Life of Base Test.]]

Kate Racaza: updated example

2012-08-01T09:12:50Z

updated example

← Older revision		Revision as of 09:12, 1 August 2012
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	{~~\| class="FCK__ShowTableBorders" border="0" cellspacing="0" cellpadding="0" align="center"; style="width:100%;"~~		<noinclude>{{Banner_ALTA_Examples}}
	\|-		</noinclude>To illustrate the principles behind accelerated testing, consider the following simple example which involves a paper clip. The objective is to determine the mean number of cycles-to-failure of the paper clip. Assume that the use cycle is a 45º bend. The acceleration stress is determined to be the angle to which the paper clip is bent. In this case, assume that the two accelerated bend stresses are 90º and 180º. For the 90º bend, test the paper clip using the following procedure. Use a similar procedure for the 180º and 45º tests.
	~~\| valign="middle" align="left" bgcolor=EEEDF7\|[[Image: ALTA-Examples-banner.png\|400px\|center]]~~
	\|}		Note that the paper clips used in this example are Jumbo paper clips that are capable of repeated bending. Different paper clips will yield different results. Additionally, and so that no other stresses are imposed, take caution to assure that the rate at which the paper clips are cycled remains the same across the experiment.
	<br>
	To illustrate the principles behind accelerated testing, consider the following simple example which involves a paper clip ~~and can be easily and independently performed by the reader~~. The objective ~~was~~ to determine the mean number of cycles-to-failure of ~~a given~~ paper clip. ~~The~~ use ~~cycles were assumed to be at~~ a 45º bend. The acceleration stress ~~was~~ determined to be the angle to which ~~we bend~~ the ~~clips~~, ~~thus~~ two accelerated bend stresses of 90º and 180º ~~were used~~. ~~The~~ paper ~~clips were tested~~ using the following procedure ~~for the 90º bend~~. A similar procedure ~~was also used~~ for the 180º and 45º ~~test~~.
			'''Paper Clip Test'''

			1) Open the Paper Clip.

			:a. With one hand, hold the clip by the longer, outer loop.

			:b. With the thumb and forefinger of the other hand, grasp the smaller, inner loop.

			:c. Pull the smaller, inner loop out and down 90º so that a right angle is formed as shown.

	~~1) '''Open the Paper Clip.'''~~
	~~<br>~~
	[[Image:openclip.gif\|thumb\|center\|300px\|]]		[[Image:openclip.gif\|thumb\|center\|300px\|]]
	~~<br>~~
	~~2) With one hand, hold the clip by the longer, outer loop.~~

	~~3) With the thumb and forefinger of the other hand, grasp the smaller, inner loop.~~

	4) ~~Pull~~ the ~~smaller, inner loop out and down 90º so that a right angle is formed as shown~~.		2) Close the Paper Clip.

	~~5) '''Close the Paper Clip.'''~~		:a. With one hand, continue to hold the clip by the longer, outer loop.
	~~<br>~~
	~~[[Image~~:~~closeclip~~.~~gif\|thumb\|center\|300px\|]]~~
	~~<br>~~
	6) With one hand, continue to hold the clip by the longer, outer loop.

	7) With the thumb and forefinger of the other hand, grasp the smaller, inner loop.		:b. With the thumb and forefinger of the other hand, grasp the smaller, inner loop.

	8) Push the smaller inner loop up and in 90º so that the smaller loop is returned to the original upright position in line with the larger, outer loop as shown.		:c. Push the smaller inner loop up and in 90º so that the smaller loop is returned to the original upright position in line with the larger, outer loop as shown.

	9) This completes one cycle.		This completes one cycle.

	~~10) Repeat until the paper clip breaks. Count and record the cycles-to-failure for each clip~~.		[[Image:closeclip.gif\|thumb\|center\|300px\|]]

			3) Repeat steps 1 and 2 until the paper clip breaks. Count and record the cycles-to-failure for each clip.

	At this point, the reader must note that the paper clips used in this example were Jumbo paper clips capable of repeated bending. Different paper clips will yield different results. Additionally, and so that no other stresses are imposed, caution must be taken to assure that the rate at which the paper clips are cycled remains the same across the experiment.

			'''Analysis'''

	~~For the~~ experiment, a sample of six paper clips ~~was~~ tested to failure at both 90º and 180º bends. A base test sample of six paper clips was tested at a 45º bend (the assumed use stress level) to confirm the analysis. The cycles-to-failure are given next.		In this experiment, a sample of six paper clips were tested to failure at both 90º and 180º bends. A base test sample of six paper clips was tested at a 45º bend (the assumed use stress level) to confirm the analysis. The cycles-to-failure are given next.


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	<br>		<br>
	~~The accelerated test~~ data ~~set was then analyzed~~ in ALTA, assuming a lognormal life distribution (fatigue) and an inverse power law relationship (non-thermal) for the life-stress model. The analysis and some of the results ~~are shown in the next figures~~.		Enter the data in an ALTA standard folio, and analyze the results assuming a lognormal life distribution (fatigue) and an inverse power law relationship (non-thermal) for the life-stress model. The following figures show the analysis and some of the results.

	[[Image:degreesbend.png~~\|thumb~~\|center\|500px\|~~The accelerated test data analyzed in~~ ALTA.]]		[[Image:degreesbend.png\|center\|500px\|ALTA Standard Folio.]]
	<br>		<br>
	<br>		<br>
	[[Image:probweib.png~~\|thumb~~\|center\|500px\|Lognormal ~~probability plot~~ of both ~~stress levels from ALTA~~.]]		[[Image:probweib.png\|center\|500px\|Lognormal Probability Plot of both Stress Levels.]]
	<br>		<br>
	<br>		<br>
	[[Image:accvsstress.png~~\|thumb~~\|center\|500px\|~~The resulting~~ Acceleration Factor vs. Stress plot ~~from ALTA~~.]]		[[Image:accvsstress.png\|center\|500px\|Acceleration Factor vs. Stress plot.]]

	<br>		<br>
	The MTTF at 45º is ~~found~~ to be 71.375467 cycles as shown next.		The MTTF at 45º is estimated to be 71.375467 cycles, as shown next.

	<br>		<br>
	[[Image:Ch12-Ex1-4.png~~\|thumb~~\|center\|500px\|~~The mean life~~ at 45º ~~bend~~.]]		[[Image:Ch12-Ex1-4.png\|center\|500px\|Mean Life at 45º Bend.]]


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	<br>		<br>
	[[Image:ALTA14.5b.gif~~\|thumb~~\|center\|500px\|~~The base~~ 45º ~~data analyzed in ReliaSoft's Weibull++, utilizing a lognormal distribution shown on lognormal probability paper~~.]]		[[Image:ALTA14.5b.gif\|center\|500px\|Base 45º Data Lognormal Probability Plot.]]

	~~<br>~~
	~~[[Image:ALTA14.5.gif\|thumb\|center\|500px\|Calculated mean life from base test.]]~~

	~~<br>~~		[[Image:ALTA14.5.gif\|center\|500px\|Mean Life of Base Test.]]

Chris Kahn at 15:37, 22 May 2012

2012-05-22T15:37:57Z

← Older revision		Revision as of 15:37, 22 May 2012
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	<br>		<br>
	The accelerated test data set was then analyzed in ALTA, assuming a lognormal life distribution (fatigue) and an inverse power law relationship (non-thermal) for the life-stress model. The analysis and some of the results are shown in the next figures.		The accelerated test data set was then analyzed in ALTA, assuming a lognormal life distribution (fatigue) and an inverse power law relationship (non-thermal) for the life-stress model. The analysis and some of the results are shown in the next figures.


	[[Image:degreesbend.png\|thumb\|center\|500px\|The accelerated test data analyzed in ALTA.]]		[[Image:degreesbend.png\|thumb\|center\|500px\|The accelerated test data analyzed in ALTA.]]
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	<br>		<br>
	The MTTF at ~~45 degrees~~ is found to be 71.375467 cycles as shown next.		The MTTF at 45º is found to be 71.375467 cycles as shown next.

	<br>		<br>

Chris Kahn at 15:35, 22 May 2012

2012-05-22T15:35:06Z

Chris Kahn at 15:33, 22 May 2012

2012-05-22T15:33:24Z

← Older revision		Revision as of 15:33, 22 May 2012
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	<br>		<br>
	To illustrate the principles behind accelerated testing, consider the following simple example which involves a paper clip and can be easily and independently performed by the reader. The objective was to determine the mean number of cycles-to-failure of a given paper clip. The use cycles were assumed to be at a 45º bend. The acceleration stress was determined to be the angle to which we bend the clips, thus two accelerated bend stresses of 90º and 180º were used. The paper clips were tested using the following procedure for the 90º bend. A similar procedure was also used for the 180º and 45º test.		To illustrate the principles behind accelerated testing, consider the following simple example which involves a paper clip and can be easily and independently performed by the reader. The objective was to determine the mean number of cycles-to-failure of a given paper clip. The use cycles were assumed to be at a 45º bend. The acceleration stress was determined to be the angle to which we bend the clips, thus two accelerated bend stresses of 90º and 180º were used. The paper clips were tested using the following procedure for the 90º bend. A similar procedure was also used for the 180º and 45º test.



	1) '''Open the Paper Clip.'''		1) '''Open the Paper Clip.'''
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	[[Image:degreesbend.png\|thumb\|center\|~~400px~~\|The accelerated test data analyzed in ALTA.]]		[[Image:degreesbend.png\|thumb\|center\|500px\|The accelerated test data analyzed in ALTA.]]
	<br>		<br>
	<br>		<br>
	[[Image:probweib.png\|thumb\|center\|~~400px~~\|Lognormal ~~probabiliyt~~ plot of both stress levels from ALTA.]]		[[Image:probweib.png\|thumb\|center\|500px\|Lognormal probability plot of both stress levels from ALTA.]]
	<br>		<br>
	<br>		<br>
	[[Image:accvsstress.png\|thumb\|center\|~~400px~~\|The resulting Acceleration Factor vs. Stress plot from ALTA.]]		[[Image:accvsstress.png\|thumb\|center\|500px\|The resulting Acceleration Factor vs. Stress plot from ALTA.]]

	<br>		<br>
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	<br>		<br>
	[[Image:Ch12-Ex1-4.png\|thumb\|center\|~~400px~~\|The ~~Mean Life~~ at ~~45 degrees~~ bend.]]		[[Image:Ch12-Ex1-4.png\|thumb\|center\|500px\|The mean life at 45º bend.]]


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	<br>		<br>
	[[Image:ALTA14.5b.gif\|thumb\|center\|~~300px~~\|The base ~~<math>45^\circ </math>~~ data analyzed in ReliaSoft's Weibull++, utilizing a lognormal distribution shown on lognormal probability paper.]]		[[Image:ALTA14.5b.gif\|thumb\|center\|500px\|The base 45º data analyzed in ReliaSoft's Weibull++, utilizing a lognormal distribution shown on lognormal probability paper.]]

	<br>		<br>
	[[Image:ALTA14.5.gif\|thumb\|center\|~~400px~~\|Calculated ~~Mean Life~~ from base test.]]		[[Image:ALTA14.5.gif\|thumb\|center\|500px\|Calculated mean life from base test.]]

	<br>		<br>

Nikki Helms: Created page with '{| class="FCK__ShowTableBorders" border="0" cellspacing="0" cellpadding="0" align="center"; style="width:100%;" |- | valign="middle" align="left" bgcolor=EEEDF7|[[Image: ALTA-Exa…'

2012-03-21T21:48:07Z

Created page with '{| class="FCK__ShowTableBorders" border="0" cellspacing="0" cellpadding="0" align="center"; style="width:100%;" |- | valign="middle" align="left" bgcolor=EEEDF7|[[Image: ALTA-Exa…'

New page

{| class="FCK__ShowTableBorders" border="0" cellspacing="0" cellpadding="0" align="center"; style="width:100%;"
|-
| valign="middle" align="left" bgcolor=EEEDF7|[[Image: ALTA-Examples-banner.png|400px|center]]
|}
<br>
To illustrate the principles behind accelerated testing, consider the following simple example which involves a paper clip and can be easily and independently performed by the reader. The objective was to determine the mean number of cycles-to-failure of a given paper clip. The use cycles were assumed to be at a 45º bend. The acceleration stress was determined to be the angle to which we bend the clips, thus two accelerated bend stresses of 90º and 180º were used. The paper clips were tested using the following procedure for the 90º bend. A similar procedure was also used for the 180º and 45º test.

1) '''Open the Paper Clip.'''
<br>
[[Image:openclip.gif|thumb|center|300px|]]
<br>
2) With one hand, hold the clip by the longer, outer loop.

3) With the thumb and forefinger of the other hand, grasp the smaller, inner loop.

4) Pull the smaller, inner loop out and down 90 degrees so that a right angle is formed as shown.

5) '''Close the Paper Clip.'''
<br>
[[Image:closeclip.gif|thumb|center|300px|]]
<br>
6) With one hand, continue to hold the clip by the longer, outer loop.

7) With the thumb and forefinger of the other hand, grasp the smaller, inner loop.

8) Push the smaller inner loop up and in 90 degrees so that the smaller loop is returned to the original upright position in line with the larger, outer loop as shown.

9) This completes one cycle.

10) Repeat until the paper clip breaks. Count and record the cycles-to-failure for each clip.

At this point, the reader must note that the paper clips used in this example were Jumbo paper clips capable of repeated bending. Different paper clips will yield different results. Additionally, and so that no other stresses are imposed, caution must be taken to assure that the rate at which the paper clips are cycled remains the same across the experiment.

For the experiment, a sample of six paper clips was tested to failure at both 90º and 180º bends. A base test sample of six paper clips was tested at a 45º bend (the assumed use stress level) to confirm the analysis. The cycles-to-failure are given next.

<div style="text-align: center;"> '''Cycles-to-Failure at <math>90^\circ </math> [[File:90degree.gif]] </div>
<br>
<div style="text-align: center;"> 16, 17, 18, 21, 22, 23 cycles.</div>
<br>
<div style="text-align: center;"> '''Cycles-to-Failure at <math>180^\circ </math> [[File:180degree.gif]]</div>
<br>
<div style="text-align: center;"> 4, 4, 5, 6, 6, 8 cycles.</div>
<br>
<div style="text-align: center;"> '''Cycles-to-Failure at <math>45^\circ </math> [[File:45degree.gif]]</div>
<br>
<div style="text-align: center;"> 58, 63, 65, 72, 78, 86 cycles.</div>

<br>
The accelerated test data set was then analyzed in ALTA, assuming a lognormal life distribution (fatigue) and an inverse power law relationship (non-thermal) for the life-stress model. The analysis and some of the results are shown in the next figures.

[[Image:degreesbend.png|thumb|center|400px|The accelerated test data analyzed in ALTA.]]
<br>
<br>
[[Image:probweib.png|thumb|center|400px|Lognormal probabiliyt plot of both stress levels from ALTA.]]
<br>
<br>
[[Image:accvsstress.png|thumb|center|400px|The resulting Acceleration Factor vs. Stress plot from ALTA.]]

<br>
The MTTF at 45 degrees is found to be 71.375467 cycles as shown next.

<br>
[[Image:Ch12-Ex1-4.png|thumb|center|400px|The Mean Life at 45 degrees bend.]]

The next two figures show the analysis of the base data in Weibull++ and the base MTTF estimate. In this case, our accelerated test correctly predicted the MTTF as verified by our base test.

<br>
[[Image:ALTA14.5b.gif|thumb|center|300px|The base <math>45^\circ </math> data analyzed in ReliaSoft's Weibull++, utilizing a lognormal distribution shown on lognormal probability paper.]]

<br>
[[Image:ALTA14.5.gif|thumb|center|400px|Calculated Mean Life from base test.]]

<br>

← Older revision		Revision as of 15:35, 22 May 2012
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	3) With the thumb and forefinger of the other hand, grasp the smaller, inner loop.		3) With the thumb and forefinger of the other hand, grasp the smaller, inner loop.

	4) Pull the smaller, inner loop out and down ~~90 degrees~~ so that a right angle is formed as shown.		4) Pull the smaller, inner loop out and down 90º so that a right angle is formed as shown.

	5) '''Close the Paper Clip.'''		5) '''Close the Paper Clip.'''
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	7) With the thumb and forefinger of the other hand, grasp the smaller, inner loop.		7) With the thumb and forefinger of the other hand, grasp the smaller, inner loop.

	8) Push the smaller inner loop up and in ~~90 degrees~~ so that the smaller loop is returned to the original upright position in line with the larger, outer loop as shown.		8) Push the smaller inner loop up and in 90º so that the smaller loop is returned to the original upright position in line with the larger, outer loop as shown.

	9) This completes one cycle.		9) This completes one cycle.
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	<div style="text-align: center;"> '''Cycles-to-Failure at ~~<math>90^\circ </math>~~ [[File:90degree.gif]] </div>		<div style="text-align: center;"> '''Cycles-to-Failure at 90º [[File:90degree.gif]] </div>
	<br>		<br>
	<div style="text-align: center;"> 16, 17, 18, 21, 22, 23 cycles.</div>		<div style="text-align: center;"> 16, 17, 18, 21, 22, 23 cycles.</div>
	<br>		<br>
	<div style="text-align: center;"> '''Cycles-to-Failure at ~~<math>180^\circ </math>~~ [[File:180degree.gif]]</div>		<div style="text-align: center;"> '''Cycles-to-Failure at 180º [[File:180degree.gif]]</div>
	<br>		<br>
	<div style="text-align: center;"> 4, 4, 5, 6, 6, 8 cycles.</div>		<div style="text-align: center;"> 4, 4, 5, 6, 6, 8 cycles.</div>
	<br>		<br>
	<div style="text-align: center;"> '''Cycles-to-Failure at ~~<math>45^\circ </math>~~ [[File:45degree.gif]]</div>		<div style="text-align: center;"> '''Cycles-to-Failure at 45º [[File:45degree.gif]]</div>
	<br>		<br>
	<div style="text-align: center;"> 58, 63, 65, 72, 78, 86 cycles.</div>		<div style="text-align: center;"> 58, 63, 65, 72, 78, 86 cycles.</div>