I need a rotational stress formula
I need a rotational stress formula
(OP)
I have one from Marks book of engineering (5-55) but it also uses terms that leads to further computation. p= mass density, lb.s^2/in^4 This has stumped me. I have no idea of what I should place in for these values. What is inches raised to the fourth? Is this mulitplied by gravity?
Don't laugh but my dog thought the leather binding was tasty. I no longer have the first chapter or the end of the index.
I only need to find the stress in a rotating disk so I can begin selecting a material.
I have tried finding this information with no result. My searches led me to this forum.
Don't laugh but my dog thought the leather binding was tasty. I no longer have the first chapter or the end of the index.
I only need to find the stress in a rotating disk so I can begin selecting a material.
I have tried finding this information with no result. My searches led me to this forum.





RE: I need a rotational stress formula
The details of MOI are beyond a simple posting. Please reference an introductory dynamics book. Look for 'moment of inertia', 'mass moment', or 'rotational acceleration'.
Brad
RE: I need a rotational stress formula
The maximum radial stress and maximum tangential stress in a solid homogeneous circular disk of uniform thickness are equal and occur at the center:
max sigmar=max sigmat=delta*omega2*(3+ni)*R2/8/386.4 lb/in2
delta=mass density lb/in3
omega=angular velocity rad/sec
R=disk radius in
ni=Poisson's ratio (0.3 for steel)
The Roark has also formulas for an annular disk and for disks with variable thickness.
prex
motori@xcalcsREMOVE.com
http://www.xcalcs.com
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RE: I need a rotational stress formula
I missed the boat on that one! Additionally my brain misfired on the units. I really shouldn't post late at night.
Go with what Prex said; please ignore my previous post, as I was definitely offbase.
Brad