===================================================== Calculating elastic properties of composite laminates

.. image:: https://img.shields.io/badge/code%20style-black-000000.svg :target: https://github.com/psf/black

The purpose of this program is to calculate some properties of fiber-reinforced composite laminates. It calculates

• engineering properties like Ex, Ey, Gxy
• thermal properties CTE_x and CTE_y
• physical properties like density and laminate thickness
• stiffness and compliance matrices (ABD and abd)

Although these properties are not very difficult to calculate, (the relevant equations and formulas can be readily found in the available composite literature) the calculation is time-consuming and error-prone when done by hand.

As of version 2020-12-22. the internals have been updated to use

• Halpin-Tsai approximation for E2 and to help calculate Ez,
• periodic micromechanics model for single plies and
• first order shear deformation theory for laminates.

This helps yield better data for FEA.

This program can not calculate the strength of composite laminates; because there are many different failure modes, strengths of composite laminates cannot readily be calculated from the strengths of the separate materials that form the laminate. These strengths have to be determined from tests.

The program has options for producing LaTeX and HTML output in addition to plain text output.

The program and its file format are documented by a manual. This can be found in the doc subdirectory.

There are basically two versions of this program; a console version primarily meant for POSIX operating systems and a GUI version primarily meant for ms-windows.

You can try both versions without installing them first, with the following invocations in a shell from the root directory of the repository.

Use python console -h for the console version, and python gui for the GUI version.

Of note

As of version 3 (2017-02-25), support for old style fiber properties (which also specified properties in the radial direction of the fiber) has been removed from the code. In the tools subdirectory of the source distribution a script called convert-lamprop.py has been provided to convert old-style lamprop files to the new format.

On 2020-10-03, lamprop has switched to using the release date as the version. So 4.2 became 2020-03-13.

The installed scripts are an archive of compiled Python bytecode. This means that you have to re-install lamprop after updating Python to a new version.

As of version 2022.01.29, lamprop contains the following generic resins;

• generic-epoxy
• generic-polyester
• generic-vinylester

And the following generic fibers;

• generic-e-glas
• generic-carbon
• generic-aramid49

You can use them in your lamprop files without having to define them. Redefinitions of these names in your lamprop file will be ignored.

Requirements

This program requires at least Python 3.6. It is not compatible with Python 2! It has no library requirments outside of the Python standard library. Development and testing is currently done using Python 3.9.

Developers ++++++++++

You will need py.test to run the provided tests. Code checks are done using pylama. Both should be invoked from the root directory of the repository.

.. _py.test: https://docs.pytest.org/ .. _pylama: http://pylama.readthedocs.io/en/latest/

Installation

To install it for the local user, run::

python setup.py install

This will install it in the user path for Python scripts. For POSIX operating systems this is ususally ~/.local/bin. For ms-windows this is the Scripts directory of your Python installation or another local directory. Make sure that this directory is in your $PATH environment variable.

On a UNIX-like operating system, you can run make install as root instead for a system-wide install. This will additionally install the manual. By default, this install is done in the /usr/local/ tree. Change the PREFIX variable in the Makefile in case you want to install somewhere else.

Vim +++

In the tools subdirectory you will find a vim_ syntax file for lamprop files. If you want to use it, copy lamprop.vim to ~/.vim/syntax, and set the filetype of your lamprop files to lamprop.

.. _vim: http://www.vim.org

You can set the filetype by adding a modeline to your lamprop files:

.. code-block:: vim

vim:ft=lamprop

This requires that modeline support is enabled. You should have the following line in your vimrc:

.. code-block:: vim

set modeline

Alternatively, if you use the .lam extension for your lamprop files you can use an autocommand in your vimrc;

.. code-block:: vim

autocmd BufNewFile,BufRead *.lam set filetype=lamprop