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.

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