Roark's Flat Circular Plate Nomenclature
Roark's Flat Circular Plate Nomenclature
(OP)
I'm wondering if someone could point me in the right direction. I'm designing a flat circular plate (fixed edges) with a uniform annular line load on it. I am using Roark's 6th Edition, Case No. 9b. I'm interested in calculating the bending moment at the center, bending moment at the outer edge, and the uniform reaction as a line... for now.
I see Mc as the moment at the center. That's straightforward. It's what to use for the outer egde that is confusing to me.
What exactly is Mra since Roark describes it as a reaction on page 398 but the plate diagram on page 428 shows Mra looking like a moment? I know the units end up being a force from using the equation.
The LT-y, LT-theta, LT-M, and LT-Q arent't defined other than "load terms." LT-Q looks very much like Qa from Case No. 9a without the singularity. Are those just load terms specific to that Case No.?
To get the moment at the edge of my circular plate do I use Mt, the unit tangential bending moment, or Mr, the unit radial bending moment? And do I simply set r = a?
I'm used to using the AISC beam diagrams. But I have a situtation where Roark's is directly applicable.
Thank you in advance.
Daniel...
I see Mc as the moment at the center. That's straightforward. It's what to use for the outer egde that is confusing to me.
What exactly is Mra since Roark describes it as a reaction on page 398 but the plate diagram on page 428 shows Mra looking like a moment? I know the units end up being a force from using the equation.
The LT-y, LT-theta, LT-M, and LT-Q arent't defined other than "load terms." LT-Q looks very much like Qa from Case No. 9a without the singularity. Are those just load terms specific to that Case No.?
To get the moment at the edge of my circular plate do I use Mt, the unit tangential bending moment, or Mr, the unit radial bending moment? And do I simply set r = a?
I'm used to using the AISC beam diagrams. But I have a situtation where Roark's is directly applicable.
Thank you in advance.
Daniel...





RE: Roark's Flat Circular Plate Nomenclature
Units look like a force: (ft-lbs)/ft or (N-m)/m
RE: Roark's Flat Circular Plate Nomenclature
RE: Roark's Flat Circular Plate Nomenclature
Mr and Mt are the moment at right angles to each other. Use whichever is larger for design.
RE: Roark's Flat Circular Plate Nomenclature
Daniel...
RE: Roark's Flat Circular Plate Nomenclature
Look in the first site below, under Plates -> Simple bending -> Solid circular pl. -> Fixed -> Line load : you'll get the same results as Roark's (hopefully), but perhaps more understandable.
prex
http://www.xcalcs.com : Online engineering calculations
http://www.megamag.it : Magnetic brakes and launchers for fun rides
http://www.levitans.com : Air bearing pads