Absorbed Energy

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PuttyTor Associate Join Date: Oct 2007 Location: Canada Posts: 32	Absorbed Energy 10/11/2007 2:57 PM
	I am trying to confirm a statement (from the supplier of sheet plastic) that says his ABS sheet can withstand an absorbed energy impact of 4.0J. I have a 550g steel ball with a diameter of 1". At what height do I need to drop the ball to confirm his claim? __________________ Two silk worms had a race. They ended up in a tie.
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ducon Guru Join Date: Dec 2006 Location: Hop around Toronto, New York & Karachi Posts: 1876 Good Answers: 19	#1 Re: Absorbed Energy 10/12/2007 1:21 AM
	What have you got against the ABS Sheet manufacturer and what do we get into going through all the maths to tell you the height. It is your job to believe in him since he must have carried out the test prior mentioning absorbed energy impact of 4.0j. If you do not believe it is then, your job to proof by: 1st. buying his sheet. 2nd. physical experiment with climbing at different heights till your 550g steel 1" ball cracks the sheet. 3rd. Paying for a new sheet and not carrying out the dumb exercise. __________________ I not only use all the brains that I have, but all that I can borrow. Woodrow Wilson
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Mr. Truman Brain Guru Join Date: Mar 2007 Location: South-east corner of Spain 50 48 49.24N 2 28 27.70W Posts: 1508 Good Answers: 31	#2 Re: Absorbed Energy 10/12/2007 2:02 AM
	Why don't you ask to see the material specification and proof of conformity for the sheet? If the supplier states that this sheet can absorb 4.0J, ask for the proof! If the supplier has any validity, they will supply the proof without batting an eyelid! __________________ “It's kind of fun to do the impossible.” Walt Disney
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SlideRule Participant Join Date: Oct 2007 Posts: 2	#3 Re: Absorbed Energy 10/12/2007 7:05 AM
	sorry i can only think in old english so please pardon me but 550g = 1.21253 lb, 4 J = 2.950249 lb-ft, height = 2.950249 lb-ft / 1.21253 lb = 2.433135 ft. you may want to test at operating temperature since i would imagine temperature would have much to do with impact strength.
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Bill Guru Join Date: Dec 2005 Location: Clemson, South Carolina Posts: 1722 Good Answers: 18	#4 In reply to #3 Re: Absorbed Energy 10/12/2007 7:56 AM
	Sliderule, how did you get that many decimal places from a sliderule? __________________ We have met the enemy and he is us . . . Walt Kelly
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Mr. Truman Brain Guru Join Date: Mar 2007 Location: South-east corner of Spain 50 48 49.24N 2 28 27.70W Posts: 1508 Good Answers: 31	#5 In reply to #4 Re: Absorbed Energy 10/12/2007 8:14 AM
	Have you seen the size of his sliderule!!( No double an-taunt intended ) __________________ “It's kind of fun to do the impossible.” Walt Disney
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Ron Guru Join Date: Dec 2005 Location: Wisconsin USA Posts: 824 Good Answers: 37	#9 In reply to #4 Re: Absorbed Energy 10/12/2007 10:49 AM
	Back in college, I had one of the cheap celluloid student slide rules with scales only on the front. When I found a source listing the first 120 places for pi, and giving several other constants to many decimals, I scribed them into the blank back surface. During the last exam of my Junior year, the physics prof had an exam problem that had the final value "2pi". He wanted results (as always) to slide rule accuracy. And that's what he got, but MY paper had about 118 more decimal places than anyone else's . . . __________________ " Ignorance and arrogance have more in common than their last four letters. "
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Anonymous Poster	#6 Re: Absorbed Energy 10/12/2007 8:48 AM
	An impact of 4 Joules can be achieved by 4 megawatts of power for 1.0 microsecond, 1.0 watt of power for 4 seconds, or any combination in between. You need to define the test conditions.
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Hottech Power-User Join Date: Nov 2006 Location: Canada Posts: 336 Good Answers: 5	#7 Re: Absorbed Energy 10/12/2007 9:59 AM
	A steel ball of .55kg dropped from .74m (29") will have 4.0J kinetic energy. How much of this will be absorbed by the ABS sheet is hard to say.
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PuttyTor Associate Join Date: Oct 2007 Location: Canada Posts: 32	#10 In reply to #7 Re: Absorbed Energy 10/12/2007 11:33 AM
	Thank you for your input. I agree with your answer of 0.74m I am assuming 100% of the engery transfered to the material. __________________ Two silk worms had a race. They ended up in a tie.
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case491 Guru Join Date: Sep 2007 Posts: 1817 Good Answers: 7	#11 In reply to #10 Re: Absorbed Energy 10/12/2007 3:26 PM
	"I am assuming 100% of the engery transfered to the material." That can't be right, surely the ball will continue to move after impact like bounce or something?
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erssk Power-User Join Date: Dec 2006 Posts: 110 Good Answers: 3	#8 Re: Absorbed Energy 10/12/2007 10:00 AM
	Never trust a manufacturer who supplies only his own test results. Ask for a test report from a third party Independent Testing Labortory. Reputable Mfg's. have no problem with that and probably have already had the testing done. Results will most likely be from a set of Charpy notched bar impact tests or Izod Impact tests. These results will give energy absorption of an ASTM standard specimen under ASTM standard test conditions. These test results may or may not be translatable to your particular application. __________________ ONE TEST IS WORTH A THOUSAND EXPERT OPINIONS
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Anonymous Poster (1); Bill (1); case491 (1); ducon (1); erssk (1); Hottech (1); Mr. Truman Brain (2); PuttyTor (1); Ron (1); SlideRule (1)

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