Diameter Of Side-Crankshaft At Juncture Of Crankweb For Max Torque Given Moments Calculator

Formula Used:

\[ d = \left( \frac{16}{\pi \cdot \tau} \cdot \sqrt{M_b^2 + M_t^2} \right)^{1/3} \]

Shear Stress in Shaft at Crank-web Joint (τ):

Resultant Bending Moment at Crank-web Joint (M_b):

N·m

Torsional Moment at Crank-web Joint (M_t):

N·m

Diameter of Crankshaft at Crank-web Joint (d):

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1. What is the Diameter of Crankshaft at Crank-web Joint?

The diameter of crankshaft at crank-web joint refers to the cross-sectional measurement at the critical junction where the crank web meets the crankshaft. This parameter is crucial for determining the structural integrity and load-bearing capacity of the crankshaft under maximum torque conditions.

2. How Does the Calculator Work?

The calculator uses the mechanical engineering formula:

\[ d = \left( \frac{16}{\pi \cdot \tau} \cdot \sqrt{M_b^2 + M_t^2} \right)^{1/3} \]

Where:

\( d \) — Diameter of crankshaft at crank-web joint (m)
\( \tau \) — Shear stress in shaft at crank-web joint (Pa)
\( M_b \) — Resultant bending moment at crank-web joint (N·m)
\( M_t \) — Torsional moment at crank-web joint (N·m)
\( \pi \) — Mathematical constant pi (approximately 3.1416)

Explanation: This formula combines both bending and torsional moments to determine the minimum required diameter that can withstand the combined stresses at the critical junction.

3. Importance of Crankshaft Diameter Calculation

Details: Accurate diameter calculation is essential for ensuring crankshaft reliability, preventing mechanical failure, optimizing weight, and maintaining engine performance under maximum torque conditions.

4. Using the Calculator

Tips: Enter shear stress in Pascals, bending moment and torsional moment in Newton-meters. All values must be positive numbers with shear stress greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: Why is this specific junction critical?
A: The crank-web junction experiences the highest stress concentrations due to the combination of bending and torsional loads, making it a common failure point.

Q2: What are typical shear stress values for crankshaft materials?
A: For forged steel crankshafts, typical allowable shear stress ranges from 40-80 MPa, depending on the specific alloy and heat treatment.

Q3: How does maximum torque affect the calculation?
A: Maximum torque conditions produce the highest torsional moments, which combined with bending moments, determine the critical diameter requirement.

Q4: Are safety factors included in this calculation?
A: This formula provides the theoretical minimum diameter. Engineering practice requires applying appropriate safety factors based on application requirements.

Q5: Can this calculator be used for other shaft diameter calculations?
A: While the principle is similar, this specific formula is optimized for crankshaft applications where combined bending and torsion occur simultaneously.