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Md Jony Islam Author
Md Jony Islam
CalculatorToolsProjectExpert
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Małgorzata Koperska, MD Steven Wooding
Last updated: October 18, 2025

Beam Bending Stress Calculator | Flexural Stress & Moment Analysis

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Beam Bending Stress Calculator

Calculate bending stress, bending moment, and section modulus for beams under loads. Step-by-step solutions with SI units included.

beam bending stress calculator:

This Stress Calculator will be used to compute the flexural stress of beams under different loads. Type of beam to enter, span, cross-section, and load. Bending stress, maximum moment, and section modulus are demonstrated by step-by-step formulae to be used in structural or mechanical analysis.

Beam Bending Stress Tool Formula:

Formula:
Bending Stress (σ) = M * c / I
Moment of Inertia (I) for Rectangular Cross-Section = b * h³ / 12
Moment of Inertia (I) for Circular Cross-Section = π * d⁴ / 64

where σ = Bending stress, M = Applied moment, c = Distance from neutral axis, I = Moment of inertia

The Beam Bending Stress Calculator can be used by engineers and students studying flexural stress with multiple loads on beams. Bending stress is caused by bending moments on the beam cross-section, which is determined by the formula:

\[ \sigma = \frac{M . y}{I} \]

Where σ is the bending stress, M is the bending moment, y is the distance from the neutral axis, and I is the moment of inertia.
The user is able to enter load applied, type of beam (simply supported, cantilever, overhanging), length of span, dimensions of beam cross-section, and material properties. The calculator determines maximum bending stress, bending moment, and section modulus, and gives solutions step by step. The SI units are supported: N, m, mm, Pa, MPa. It has optional features such as plotting bending moment diagrams, calculating deflection, and printing results. It is a tool that can be used by structural engineers, mechanical engineers, students, and educators to perform an analysis of beam strength, safety, type, and structural performance.

⚡ Work & Installation Input to Output:

Input:

  • Beam type: simply supported, cantilever, overhanging
  • Span length (L)
  • Load: point load (P) or uniform distributed load (w)
  • Cross-section: width (b), height (h) or radius (r), I-section properties
  • Distance from neutral axis (y)
  • Units: N, m, mm, Pa/MPa

Processing:

  • Compute bending moment (M) based on beam type and loading:
  • Simply supported point load: M_max = P × L / 4
  • Cantilever point load: M_max = P × L
  • Uniform distributed load: M_max = w × L² / 8
  • Compute moment of inertia (I) for cross-section:
  • Rectangular: I = b × h³ / 12
  • Circular: I = π × d⁴ / 64
  • Compute bending stress: σ = M × y / I
  • Compute section modulus: S = I / y

Output:

  • Maximum bending stress (σ_max)
  • Maximum bending moment (M_max)
  • Section modulus (S)
  • Step-by-step formulas
  • Optional bending moment diagram and printable results

Testing and Final Adjustments

Test common scenarios:

  • Simply supported beam, P = 1000 N, L = 2 m, rectangular section b = 0.1 m, h = 0.2 m → compute M_max, I, σ_max
  • Cantilever beam with w = 500 N/m, L = 1.5 m → validate formulas
  • Circular cross-section: d = 0.1 m → compute I, σ
  • Edge cases: zero load, extremely long span, thin cross-section → check stress calculation
  • Validate units (Pa ↔ MPa, N·m for moment)
  • Step-by-step solution clarity
  • Mobile/desktop UX: numeric keypad, labels, error messages for invalid inputs
  • Include preset examples for educational and professional use
  • Optimize SEO metadata: "Beam Bending Stress Calculator," "Flexural Stress," "Bending Moment," "Section Modulus," schema markup

Frequently Asked Questions - Beam Bending Stress Calculator:

What is bending stress in a beam?

Bending stress is the internal stress developed in a beam due to bending moments acting on the cross-section.

How do I calculate bending stress?

σ = M × y / I, where M is bending moment, y is distance from neutral axis, and I is moment of inertia.

How do I calculate bending moment?

Depends on beam type and load: for simply supported point load, M_max = P × L / 4; for cantilever point load, M_max = P × L; for UDL, M_max = w × L² / 8.

What is the section modulus?

S = I / y, a measure of the beam's strength to resist bending.

Which units are supported?

N, m, mm, Pa or MPa for stress, N·m for moment.

Can I use this for rectangular or circular beams?

Yes, it supports rectangular, circular, and I-section beams.

Is step-by-step solution available?

Yes, formulas and substitutions are displayed step-by-step.

Who should use this calculator?

Structural and mechanical engineers, students, educators analyzing beam strength.

Can it handle uniform and point loads?

Yes, it can compute bending stress for both point and distributed loads.

Can it plot bending moment diagrams?

Yes, optional plotting of bending moment along the beam is available.

Md Jony Islam

Md Jony Islam

CalculatorToolsProject

Founder of Earthbondhon.com

a free online tools website designed to make everyday and engineering-related calculations easier for students, professionals, and hobbyists. The site offers a wide range of basic calculators across key categories, including Electrical Calculators, Electronic Calculators, and Time & Date Calculators.