Where (G) is the shear modulus of elasticity (77 GPa for steel), and (L) is the length of the shaft (2.5 m).
Setting: Engineering Lab, Coast Guard Inspection Yard. 2:00 AM. Mechanics Of Materials 7th Edition Chapter 3 Solutions
"Material spec says yield shear strength is 60 MPa," Leo said. "We're below yield. So why did it fail?" "Because you didn't check the angle of twist ," Dr. Vance said. "Turn to Equation 3-15." Where (G) is the shear modulus of elasticity
[ \tau_max = \fracTcJ ]
Leo solved: [ d = \sqrt[3]\frac16T\pi \tau_allow ] [ d = \sqrt[3]\frac16(4000)\pi (24\times10^6) = 0.094 \text m \approx 94 \text mm ] Mechanics Of Materials 7th Edition Chapter 3 Solutions
[ \phi = \frac(4000)(2.5)(3.106\times10^-6)(77\times10^9) ] [ \phi = 0.0418 \text radians \approx 2.4 \text degrees ]