Circular shaft of length 'G=90kN//mm^(2)' rotating at a speed of 150 r...
**Problem Statement**
We are given the following information:
- Length of the shaft (L) = 2 m
- Power transmitted (P) = 100 N/mm^2
- Maximum permissible shear stress (τ_max) = 60 kW
- Speed of rotation (N) = 150 rpm
We need to determine the required minimum diameter for the shaft and the corresponding angle of twist produced in the shaft.
**Solution**
To solve this problem, we will use the formula for power transmitted by a circular shaft:
\(P = \frac{2π}{60}NT\)
where P is the power transmitted, N is the speed of rotation in rpm, and T is the torque transmitted by the shaft. The torque can be calculated using the formula:
\(T = \frac{π}{16}d^3τ\)
where d is the diameter of the shaft and τ is the shear stress.
**Step 1: Calculate the Torque Transmitted**
Given that the power transmitted (P) is 100 N/mm^2 and the speed of rotation (N) is 150 rpm, we can calculate the torque transmitted (T) using the formula:
\(P = \frac{2π}{60}NT\)
Substituting the given values, we get:
\(100 = \frac{2π}{60} \times 150 \times T\)
Simplifying, we find:
\(T = \frac{100 \times 60}{2π \times 150}\)
\(T ≈ 0.636 \text{ kNm}\)
**Step 2: Calculate the Minimum Diameter**
Given that the maximum permissible shear stress (τ_max) is 60 kW and the torque transmitted (T) is 0.636 kNm, we can calculate the minimum diameter (d) using the formula:
\(T = \frac{π}{16}d^3τ\)
Substituting the given values, we get:
\(0.636 = \frac{π}{16}d^3 \times 60 \times 10^3\)
Simplifying, we find:
\(d^3 = \frac{0.636 \times 16}{π \times 60 \times 10^3}\)
\(d ≈ \sqrt[3]{\frac{0.636 \times 16}{π \times 60 \times 10^3}}\)
\(d ≈ 0.042 \text{ m}\)
**Step 3: Calculate the Angle of Twist**
Given that the length of the shaft (L) is 2 m and the minimum diameter (d) is 0.042 m, we can calculate the angle of twist (θ) using the formula:
\(θ = \frac{TL}{Gd^4}\)
Substituting the given values, we get:
\(θ = \frac{0.636 \times 10^3 \times 2}{90 \times 10^9 \times 0.042^4}\)
Simplifying, we find:
\(θ ≈ 0.001 \text{ rad}\)
Therefore, the required minimum diameter for the shaft is approximately 0.042 m and the corresponding angle of twist produced in the shaft is approximately 0.001 rad.