Fatigue Limit Calculator (Goodman / Gerber / Soderberg)

Fatigue Limit Calculator (Goodman / Gerber / Soderberg) | Online Free Tool | Elysia Tools

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Math & Numbers
Input types: number
Output type: json
Sample coverage: 4
API ready: Yes

Overview

The Fatigue Limit Calculator estimates fatigue safety factors under cyclic loading using the Modified Goodman, Gerber, and Soderberg criteria. Enter stress amplitude, mean stress, and the applicable material strengths to compare criteria, identify the governing minimum safety factor, and check the operating point against the Goodman line.

When to use

Evaluate fatigue safety under cyclic loading with a known stress amplitude and mean stress.
Compare Goodman, Gerber, and Soderberg mean-stress correction criteria during mechanical design.
Check whether an operating point falls inside the Goodman line and identify the most conservative criterion.

How it works

1Enter the alternating stress amplitude σ_a in MPa; this value must be greater than zero.
2Enter the mean stress σ_m and the material properties required for the selected calculations: ultimate strength σ_uts, endurance limit σ_-1, and yield strength σ_y.
3The calculator computes Goodman, Gerber, and Soderberg safety factors when their required inputs are available.
4The result reports the smallest, governing safety factor and whether the point is inside or outside the Goodman line.

Use cases

Preliminary fatigue checks for shafts, brackets, fasteners, and other cyclically loaded components.
Comparison of conservative and less conservative mean-stress correction methods for material selection and design review.
Screening operating points before detailed fatigue testing or a broader mechanical design analysis.

Examples

1. Compare three fatigue criteria for a steel component

Mechanical design engineer

Background

A component experiences a 100 MPa stress amplitude and a 200 MPa tensile mean stress. Its material data are available for all three criteria.

Problem

Determine the safety factor from each criterion and identify the governing result.

How to use

Enter σ_a = 100 MPa, σ_m = 200 MPa, σ_uts = 800 MPa, σ_-1 = 300 MPa, and σ_y = 500 MPa.

Decimal places: 4

Outcome

Goodman n = 1.7143, Gerber n = 2.8125, and Soderberg n = 1.3636. Soderberg governs, and the point is inside the Goodman line.

2. Screen a high mean-stress fatigue condition

疲劳分析工程师

Background

A cyclic load produces a 150 MPa stress amplitude and a 300 MPa tensile mean stress in a material with σ_uts = 600 MPa, σ_-1 = 250 MPa, and σ_y = 400 MPa.

Problem

Check whether the operating point satisfies the Goodman criterion and find the most restrictive safety factor.

How to use

Enter σ_a = 150 MPa, σ_m = 300 MPa, σ_uts = 600 MPa, σ_-1 = 250 MPa, and σ_y = 400 MPa.

FAQ

What does the stress amplitude represent?

Stress amplitude is σ_a = (σ_max − σ_min) / 2, expressed in MPa. It must be greater than zero.

What does mean stress represent?

Mean stress is σ_m = (σ_max + σ_min) / 2. Tensile mean stress generally reduces fatigue safety.

Which material inputs are needed?

Goodman and Gerber require ultimate strength σ_uts and endurance limit σ_-1. Soderberg also requires yield strength σ_y.

What is the governing safety factor?

It is the smallest safety factor among the available Goodman, Gerber, and Soderberg results.

What does a safety factor below 1 mean?

A value below 1 indicates that the calculated operating condition does not meet that criterion.

Decimal places: 4

Run this tool

Examples that match this tool

Continue with connected tools and hubs

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Compare three fatigue criteria for a steel component

2. Screen a high mean-stress fatigue condition

FAQ

Copyright-Free MP3 Audio Samples

Web Image Processing Python Samples

SVG Samples

Android Image Processing Java Samples

Angular Velocity Converter (rad/s / rpm / deg/s / Hz)

Free Water Clearance Calculator

AI RAG Chunk Quality Scorer

Duct Size Calculator (Flow Rate × Velocity)