A) A cross-section of a solid circular rod is subject to a torque of T = 3.5 kNâ‹…m. If the diameter of the rod is D = 5 cm, what is the maximum shear stress? include units.B) The maximum stress in a section of a circular tube subject to a torque is Tmax = 37 MPa . If the inner diameter is Di = 4.5 cm and the outer diameter is Do = 6.5 cm , what is the torque on the section? include units.

Respuesta :

Answer:

[tex]\tau_{max}  = 142.6[/tex] MPa

T = 1536.8 N m

Explanation:

Given data:

Torque = 3.5 k N m = 3.5*10^3 N.m

Diameter D = 5 cm = 0.05 m

a) from torsional equation we have

[tex]\frac[T}{J_{solid}} = \frac{\tau_{max}}{D/2}[/tex]

[tex]\frac{T}{\pi/32 D^4} = \frac{\tau_{max}}{D/2}[/tex]

solving for [tex]\tau_{max}[/tex]

[tex]\tau_{max} = \frac{16 T}{\pi D^3} =\frac{16 \times 3.5*10^3}{\pi 0.05^3}[/tex]

[tex]\tau_{max}  = 142.6[/tex] MPa

B)

[tex]\tau = 37 MPa = 37 \times  10^6[/tex] Pa

[tex]D_i = 4.5 cm = 0.045[/tex] m

[tex]D_o = 6.5 cm = 0.065[/tex] m

[tex]\frac{T}{J_{hollow}} = \frac{\tau_{max}}{D_o /2}[/tex]

[tex]\frac{T}{(\pi/32) (0.065^4 - 0.045^4)} =\frac{37*10^6}{0.065/2}[/tex]

T = 1536.8 N m