Easigrow

Create models of fatigue crack growth

Easigrow is a fatigue crack growth program that specialises in calculating model coefficients that best fit crack growth data.

Easigrow is based on the Australian Defence Science and Technology report: A guide to the program easigro for generating optimised fatigue crack growth models, Paul White, DST-Group-TR-3566, Feb. 2019.

Note the addition of 'w' here for the code on Github. The version number has also been reset to 0.0.0.

Features

• Calculates the crack growth size
• Choice of beta models, material properties and crack growth equations
• Optimises model coefficients to match data
• Generates a pseudo image of the crack growth patterns

Getting started

Easigrow provides both a command line tool for running simulations and a Rust library for writing your own algorithms using the pre-existing building blocks.

Here is a simple example of growing a crack from the command line:

easigrow -q data/rainflow-seq2.txt -s 300 -n 100

#  easigrow: version 0.0.0
#  
#  Options: 
#  a: [0.00001, 0.00001]
...
       block            a 
      0.0000  1.000000e-5 
    100.0000  2.189452e-5 
    200.0000  5.234739e-4 
    204.0975  7.473615e-4 
#  Failure Event: a[0.0007473615299278992, 0.0010002610857908832] >= a_limit[0.001, 0.001]

Documentation

The following documentation contains most of what is in the above report:

• help easigrow --help command line options
• list easigrow --list output variables, beta models, da/dN data
• dadn dadn equations used (incomplete because of markdown)
• grow grow the crack
• optimisation How to optimsise a model
• fracto generate a pseudo-fracto image
• sequences Supplied loading sequences
• summary Summarise a sequence

You can also run Cargo doc to generate documentation for all the library public functions and use Easigrow as a library inside your own code.

Installation as a command line tool

You will need a stable Rust compiler, grab one if you do not have one yet. Then, you can download the code, build it and install it by running:

cargo install --git https://github.com/needsglasses/easigrow

This will produce the easigrow binary in ~/.cargo/bin.

Usage as a library

You can add Easigrow as a dependency in your project's Cargo.toml:

[dependencies]
easigrow = {git = "https://github.com/needsglasses/easigrow"}

Contributing

Contributions to Easigrow are welcome. There are several ways to help: improving the documentation; testing the code on your systems to find bugs; adding new algorithms or data; providing feature requests.

See the AUTHORS file for a list of contributors to the code.

License

This software is licensed under the MIT license, see the LICENSE-MIT file for legal text.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, shall be licensed under the same MIT license, without any additional terms or conditions.

Other Programs

Fatigue crack growth programs

• Afgrow USAF crack growth software for Windows
• Nasgro NASA crack growth software with large material library
• Fastran Crack growth using closure in Fortran

and some other open source programs on Github:

• pdprop Simulation of metal fatigue crack propagation with accounting for material memory effects in Fortran
• FCGR Fatigue Crack Growth in Reliability using R
• metal-fatigue Start of a fatigue library in Python with some rainflow counting routines
• fatpack: Python fatigue routines