S-N Curve Calculator

Are you working on a project that requires analysis of fatigue life for different materials? Do you want to quickly and accurately calculate the number of cycles a material can endure before failure? Look no further than the revolutionary S-N Curve Calculator! This powerful tool allows for the easy generation of stress-life (S-N) curves and provides accurate information on fatigue strength properties for a wide range of materials. With just a few clicks, users can input stress levels and the number of cycles, and receive a clear, comprehensive graph outlining the material's behavior over time. Whether it's for materials testing, engineering projects, or research and development purposes, the S-N Curve Calculator is an invaluable resource for anyone working with fatigue analysis. Say goodbye to complicated calculations and tedious manual plotting, and let this user-friendly tool do the work for you. Get started today and streamline your materials testing process!

S-N Curve Calculator

Calculate the fatigue life of a material based on the S-N Curve.

S-N Curve Calculator Results
Surface Finish0
Load Type0
Cycle Type0
Fatigue Life0

How to Use the S-N Curve Calculator

The S-N Curve Calculator is a powerful tool for calculating the fatigue life of a material based on the S-N Curve. Fatigue life estimation is crucial in engineering and materials science to ensure the reliability and durability of structures and components subjected to cyclic loading. This calculator simplifies the process by providing a user-friendly interface to input the necessary parameters and obtain the fatigue life estimation.

Instructions for Utilizing the S-N Curve Calculator

To utilize the S-N Curve Calculator effectively, follow these steps:

  • Material: Enter the name or type of material being analyzed. This information helps in selecting the appropriate S-N curve for the material.
  • Load: Input the magnitude of the load applied to the material. Specify the load in kilonewtons (kN). Understanding the applied load is crucial for fatigue life estimation.
  • Temperature: Enter the temperature at which the material is being tested or used. Specify the temperature in degrees Celsius (°C). Temperature influences material properties and can affect fatigue behavior.
  • Surface Finish: Choose the surface finish of the material from the provided options: Smooth or Rough. The surface finish affects the material's fatigue resistance and should be considered during analysis.
  • Radius: Input the radius of curvature for the component or structure being analyzed. Specify the radius in millimeters (mm). The radius of curvature affects the stress distribution and can impact fatigue life.
  • Load Type: Select the type of load applied to the material from the provided options: Axial, Bending, or Torsion. Different load types have varying effects on the material's fatigue behavior.
  • Corrosion: Choose the level of corrosion exposure experienced by the material from the provided options: None, Light, Moderate, or Severe. Corrosion significantly affects the material's fatigue properties and must be accounted for in the analysis.
  • Cycle Type: Select the type of loading cycle from the available options: Constant Amplitude, Block, or Variable Amplitude. The loading cycle type plays a crucial role in fatigue life estimation.

Once you have entered all the required information, click on the Calculate Fatigue Life button. The calculator will process the data and provide the following results:

  • Material: The name or type of material provided in the input.
  • Load: The magnitude of the load applied to the material.
  • Temperature: The temperature at which the material is being tested or used.
  • Surface Finish: The surface finish of the material.
  • Radius: The radius of curvature for the component or structure.
  • Load Type: The type of load applied to the material.
  • Corrosion: The level of corrosion exposure experienced by the material.
  • Cycle Type: The type of loading cycle.
  • Fatigue Life: The estimated fatigue life of the material based on the input parameters.

S-N Curve Calculator Formula

The S-N Curve Calculator estimates the fatigue life using the S-N curve approach. The S-N curve relates the applied stress level (S) to the number of cycles to failure (N) for a specific material. The relationship can be expressed mathematically as:

N = A * (S^B)


  • N is the fatigue life (number of cycles to failure).
  • S is the applied stress level.
  • A and B are material-specific constants determined from the S-N curve.

Illustrative Example

Let's consider an example to demonstrate the usage of the S-N Curve Calculator. Suppose we have a steel component made of AISI 4140. We want to estimate its fatigue life under an axial load of 50 kN at a temperature of 25°C. The component has a smooth surface finish, a radius of 100 mm, and experiences constant amplitude loading. There is no corrosion present. Here are the steps to follow:

  • Material: Enter AISI 4140 in the material field.
  • Load: Input 50 in the load field.
  • Temperature: Enter 25 in the temperature field.
  • Surface Finish: Select Smooth from the dropdown.
  • Radius: Input 100 in the radius field.
  • Load Type: Choose Axial from the dropdown.
  • Corrosion: Select None from the dropdown.
  • Cycle Type: Choose Constant Amplitude from the dropdown.

After clicking the Calculate Fatigue Life button, the calculator will provide the estimated fatigue life for the given parameters.

Illustrative Table Example

Below is an illustrative table showing multiple rows of example data. Each row represents a different set of input parameters and the corresponding fatigue life estimation.


Load (kN)

Temperature (°C)

Surface Finish

Radius (mm)

Load Type


Cycle Type

Fatigue Life

AISI 41405025Smooth100AxialNoneConstant Amplitude500,000 cycles
Aluminum 60613050Rough75BendingLightVariable Amplitude1,200,000 cycles
Titanium Ti-6Al-4V80-10Smooth150TorsionSevereBlock800,000 cycles

Please note that the values in the table are for demonstration purposes only and may not reflect actual fatigue life estimations.

The S-N Curve Calculator simplifies the process of estimating the fatigue life of materials based on the S-N curve. By inputting relevant parameters such as material, load, temperature, surface finish, radius, load type, corrosion, and cycle type, engineers and researchers can obtain valuable insights into the expected fatigue behavior of components and structures. This tool empowers users to make informed decisions regarding design, material selection, and maintenance strategies, ensuring the reliability and safety of various applications in engineering and beyond.

About the Author

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Shuvo Shaha
Python Developer

Shuvo Shaha is a skilled Python developer with expertise in developing efficient and user-friendly web applications. He is passionate about writing clean and maintainable code and is always exploring new technologies to improve his skills. With a strong background in computer science, Shuvo has experience working with a variety of frameworks and libraries, including Django and Flask. He is a collaborative team player who is dedicated to delivering high-quality work on time and on budget.