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Need help with school work again.. This time with strength testing
The filthy indian TA gave us a long list of equations for this crap, but none of them have anything to do with break strength under tension. I have ultimate tensile strength for steel equals BHN time 500, but that's not the break strength. Anyway, here's the question.
At what load would a .275" diameter by 6" long steel specimen break in tension if the hardness of the specimen was 321 BHN? This crap is due in less than an hour and this is the only problem I've had trouble on. |
Re: Need help with school work again.. This time with strength testing
Originally Posted by Secondaries
The filthy indian TA gave us a long list of equations for this crap, but none of them have anything to do with break strength under tension. I have ultimate tensile strength for steel equals BHN time 500, but that's not the break strength. Anyway, here's the question.
At what load would a .275" diameter by 6" long steel specimen break in tension if the hardness of the specimen was 321 BHN? This crap is due in less than an hour and this is the only problem I've had trouble on. |
Re: Need help with school work again.. This time with strength testing
the maximum tensile stress that a material is capable of withstanding without breaking under a gradually and uniformly applied load. Other terms that are commonly used to express the same thing are Ultimate Tensile Strength and less accurately, Breaking Strength. |
Re: Need help with school work again.. This time with strength testing
Ultimate tensile stress is not breaking stress. Once you reach the ultimate stress, the stress will continue to decrease due to necking (thus cross sectional area reducing) until you reach your failure stress.
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Re: Need help with school work again.. This time with strength testing
Originally Posted by jagojon3
Ultimate tensile stress is not breaking stress. Once you reach the ultimate stress, the stress will continue to decrease due to necking (thus cross sectional area reducing) until you reach your failure stress.
I have turned this report in, and answered the question sort of half-assed. I got to class early and the general concensus was just to plug ultimate tensile strength into the equation UTS = 500(BHN), then use the answer to derive P in the equation UTS = P(true load)/A(cross sectional area at break). That still only gives load at ultimate tensile strength, but that was how everyone else in class did it, and none of them could find another way either. |
Re: Need help with school work again.. This time with strength testing
Well were you supposed to use engineering stress or true stress?
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Re: Need help with school work again.. This time with strength testing
Does not specify, but I take it that engineering stress is the same thing as nominal stress? If so, that the opposite of what I solved for.
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Re: Need help with school work again.. This time with strength testing
Originally Posted by bigdaddyvtec
Get a Tutor with great big tits.... :6
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Re: Need help with school work again.. This time with strength testing
Originally Posted by jagojon3
Ultimate tensile stress is not breaking stress. Once you reach the ultimate stress, the stress will continue to decrease due to necking (thus cross sectional area reducing) until you reach your failure stress.
Yield strength: The stress at which material strain changes from elastic deformation to plastic deformation, causing it to deform permanently. Ultimate strength: The maximum stress a material can withstand. Breaking strength: The stress coordinate on the stress-strain curve at the point of rupture. |
Re: Need help with school work again.. This time with strength testing
Originally Posted by d-man
wrong...
Yield strength: The stress at which material strain changes from elastic deformation to plastic deformation, causing it to deform permanently. Ultimate strength: The maximum stress a material can withstand. Breaking strength: The stress coordinate on the stress-strain curve at the point of rupture. |
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