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Bredt-Batho Thin-Walled Closed Tube Torsion & Shear Flow Calculator

R. Bredt and Batho proved that for any single-cell thin-walled closed tube under pure torsion, shear flow q is constant around the circumference.

External twisting torque on closed tube

Area enclosed by median wall contour line

Wall thickness at point of shear evaluation

Calculated Result
38.5 MPa

Torsional Shear Stress (τ)

Shear Flow (q)

230.8 kN/m

Calculation Breakdown

  1. Bredt-Batho Torsion Formulaτ = T / (2 · Am · t) => 38.5 MPa

Shear Stress vs Wall Thickness

Interactive visualization based on your current inputs

τ
0.014294358t = 4 mmt = 6 mmt = 10 mmThickness (mm)Stress (MPa)

What Is the Bredt-Batho Thin-Walled Closed Tube Torsion & Shear Flow Calculator?

R. Bredt and Batho proved that for any single-cell thin-walled closed tube under pure torsion, shear flow q is constant around the circumference.

Maximum shear stress occurs wherever wall thickness t is thinnest.

How Does the Bredt-Batho Thin-Walled Closed Tube Torsion & Shear Flow Calculator Work?

The calculation evaluates user-provided measurements using recognized domain equations, converts between measurement units, and adjusts for real-world efficiency factors.

Bredt-Batho Thin-Walled Closed Tube Torsion & Shear Flow Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

q = \frac{T}{2 A_m}, \quad \tau = \frac{q}{t} = \frac{T}{2 A_m t}

Bredt-Batho shear flow and torsional shear stress formulas.

How to Use the Bredt-Batho Thin-Walled Closed Tube Torsion & Shear Flow Calculator

  1. Enter your primary measurements in the input fields above.
  2. Select your preferred units (e.g. metric or imperial) if applicable.
  3. Review or adjust operational assumptions such as field efficiency.
  4. Click Calculate to instantly generate the full results breakdown and visual chart.
  5. Use the Reset button at any time to clear the form and test a new scenario.

Step-by-Step Example Calculation

Steel Box Girder Diaphragm

Input Values:

appliedTorqueKnm:45.0
enclosedAreaMm2:80000
wallThicknessMm:8.0

Understanding Your Result

Your calculated result represents the realistic operational capacity or baseline output under the specified conditions. Comparing theoretical and effective outputs reveals the direct impact of turns, overlap, and practical downtime.

Factors That Affect the Result

Field terrain, operator experience, equipment maintenance, overlap margin, and weather conditions can significantly influence real-world output.

When Should You Use This Calculator?

Use this calculator whenever you need quick, verified estimates for job planning, budgeting, equipment sizing, or project timelines.

Assumptions & Limitations

  • Applies to arbitrary closed tube profiles (box girders, aircraft wings, aerodynamic struts).

Frequently Asked Questions

Calculation Accuracy & Reference Note

This calculator implements verified, deterministic mathematical equations based on published standards. Results should be treated as professional engineering estimates; always verify critical operations with local equipment manuals and site inspections.

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