hollow rectangular shear formula

huangyhg

hollow rectangular shear formula
hi can any one suggest me which formula is used to find transverse shear stress of hollow rectangular section
for example for hollow circular section i have
code
tau=2*v/a
for circular solid section
code
tau=(4/3)*v/a
thanks
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you could always use vq/i.  i don't have a specific hollow section formula.
depends on what you need it for.  the structural codes are generally set up for average shear on the web, not vq/i.
this site explains the theory
good point stephen.  determination of allowable v does vary from code to code.  but, the tau's he stated are from engineering mechanics.
one book that i have gives:
tau = 2.25*v/a
but this is only for a squarefff"> hollow tube, not a rectangular one.  the book i have does not give a formula for the rectangular hollow tube.
tau= vq/ib for rectangle beam:
tau= vq/it for thin walled open cross-section (t= wall thickness)
for torsion:
generally used v/l where l is the length of the steel cross section.  if a largely rectangular, i usually neglect the length of the short sides.  depending on the mood, for the latter, i sometimes use 1.5 x shear obtained to correct for the parabolic stress distribution.
for shear:
generally use the length of the side affected by torsion and if the depth is greater than twice the width, use the 1.5x noted above.
dik
thank you all
well, i don't follow some of these posts ...
for torque, stress = t/(2[a]t)
where [a] = b*d (approximately)
for shear load = v/(2lt)
where l = the side length along the applied load.
this is approximately the average shear, neglecting the parabolic distribution and neglecting the contribution of the short sides (directly)
hi,
i came across this post as i was trying to solve just this problem.  machine design and mechanics of materials books don't do the square or rectangular tube (generally) since it is a little more difficult, an exception is juvinall and marshek 3rd ed. the question asked was what is the transverse shear stress (which results from a transverse applied load, i.e., bending). the general solution is tau = (v q) / (i b), where v is the shear load, i is the second moment of area, b is the width of the beam, and q is the integral of y da over some cross-section of the beam {it is the first moment of area for the region of interest about the neutral axis}. so to get the answer for a rectangle of say b width and h height and wall thickness t, at the neutral axis where it will be maximum we need to break the integral into two parts: first from the distal fibers (h/2) to the inside of the tube wall (h/2 - t) and second integrate from the inside wall of the tube to the neural axis, i.e, (h/2 - t) to 0. note that the "b" is not the same for these two since the b in this expression is the "width" at the top of cross-section that is being integrated. so, with the help of mathematica here is the maximum transverse shear stress (at the neutral axis) for a hollow rectangular tube of width b, height h, and wall thickness t.
tautransverse =  2 t^4 - 2 h t^3 +(1/2) (h^2 - b^2) t^2 + (1/2) b^2 t
hope this helps.