Total Compressive Stress At Central Plane Of Crank Web Of Centre Crankshaft At TDC Position Calculator

Formula Used:

\[ \sigma_t = \frac{R_{v1}}{w \times t} + \frac{6 \times R_{v1} \times (b_1 - \frac{l_c}{2} - \frac{t}{2})}{w \times t^2} \]

Vertical Reaction at Bearing 1 (R_v1):

Width of Crank Web (w):

Thickness of Crank Web (t):

Centre Crankshaft Bearing1 Gap from CrankPinCentre (b₁):

Length of Crank Pin (l_c):

Total Compressive Stress in Crank Web (σ_t):

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1. What is Total Compressive Stress in Crank Web?

Total compressive stress in crank web central plane is the sum of compressive stress in crank web central plane and bending stress in crankpin. It represents the total stress experienced by the crank web at the top dead center (TDC) position in a centre crankshaft.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \sigma_t = \frac{R_{v1}}{w \times t} + \frac{6 \times R_{v1} \times (b_1 - \frac{l_c}{2} - \frac{t}{2})}{w \times t^2} \]

Where:

\( \sigma_t \) — Total compressive stress in crank web (Pa)
\( R_{v1} \) — Vertical reaction at bearing 1 (N)
\( w \) — Width of crank web (m)
\( t \) — Thickness of crank web (m)
\( b_1 \) — Centre crankshaft bearing1 gap from crankpin centre (m)
\( l_c \) — Length of crank pin (m)

Explanation: The first term represents the direct compressive stress, while the second term accounts for the bending stress component.

3. Importance of Compressive Stress Calculation

Details: Accurate compressive stress calculation is crucial for designing robust crankshafts, ensuring structural integrity, preventing fatigue failure, and optimizing engine performance at TDC position where maximum stresses occur.

4. Using the Calculator

Tips: Enter all values in appropriate SI units (Newtons for force, meters for dimensions). Ensure all values are positive and physically meaningful for accurate results.

5. Frequently Asked Questions (FAQ)

Q1: Why is TDC position critical for stress analysis?
A: At TDC position, the crank web experiences maximum compressive forces due to combustion pressure and inertial forces, making it the most critical position for stress analysis.

Q2: What are acceptable stress levels for crank webs?
A: Acceptable stress levels depend on the material properties, but typically should be well below the yield strength with appropriate safety factors for fatigue considerations.

Q3: How does crank web geometry affect stress distribution?
A: Width and thickness significantly influence stress distribution - thicker and wider webs generally reduce stress concentrations but increase weight and inertia.

Q4: Are there limitations to this formula?
A: This formula provides a simplified analysis and may not account for complex stress concentrations, thermal effects, or dynamic loading conditions in actual engine operation.

Q5: Should this calculation be used for final design validation?
A: For final design validation, finite element analysis (FEA) and experimental testing are recommended to complement this analytical calculation.