3pc-ply

3pc-ply is a Python library used to define and compute the properties of a composite ply based on classical lamination theory. It provides a Ply class to define ply properties like angle and thickness, built upon an Orthotropic material (provided by the 3pc-material package).

Installation

Use the package manager pip to install 3pc-ply. Since both 3pc-ply and 3pc-material are publicly available on PyPI, you can install them directly:

pip install 3pc-ply 3pc-material

API Reference

Ply Class

The primary component of this package is the Ply class, which holds geometric properties of the ply and dynamically calculates transformed stiffness matrices and expansion vectors.

from ply.ply import Ply

Required Parameters

When initializing Ply directly, the following parameters are required:

• plyID (str): Ply identifier.
• angle (float): Ply angle in degrees.
• material (Orthotropic): An instance of material.Orthotropic representing the material properties of the ply (Note: Orthotropic is defined in the 3pc-material package).
• thickness (float): Ply thickness.

Calculated Properties

The class automatically calculates the following properties lazily:

• Q: Reduced stiffness matrix of the ply in material orthotropy (1-2 axes).
• T: Transformation matrix to convert tensorial stress/strain between reference axes (x-y) and material orthotropy (1-2).
• R: Conversion matrix to convert tensorial strain matrix into engineering strain matrix.
• Qbar: Transformed reduced stiffness matrix in reference coordinate axes (x-y).
• Q44, Q55: Transverse stiffness in material direction.
• Q44bar, Q45bar, Q55bar: Transformed transverse stiffness in reference coordinate axes (x-y).
• alpha: Thermal expansion vector in material coordinate axes (1-2).
• beta: Hygral (moisture) expansion vector in material coordinate axes (1-2).
• alphabar: Transformed thermal expansion vector in reference coordinate axes (x-y).
• betabar: Transformed hygral expansion vector in reference coordinate axes (x-y).

Methods

Ply.fromDict(**kwargs)

Initializes a Ply instance using a dictionary of keyword arguments. This is ideal for loading configurations from JSON files or dictionaries.

Usage Examples

Basic Initialization

Below is an example of defining an orthotropic material and creating plies at different angles.

from material.orthotropic import Orthotropic
from ply.ply import Ply

# Define the material first
zg_material = Orthotropic(
    matID="zg",
    E1=181.0, 
    E2=10.3,
    G12=7.17, 
    G13=7.17, 
    G23=7.17, 
    v12=0.28
)

# 0-degree ply
ply_0_deg = Ply(
    plyID="1", 
    angle=0.0, 
    material=zg_material, 
    thickness=0.125
)

# 90-degree ply
ply_90_deg = Ply(
    plyID="2", 
    angle=90.0, 
    material=zg_material, 
    thickness=0.125
)

# Access Computed Properties
print("Q Matrix (0-deg ply):\\n", ply_0_deg.Q)
print("Qbar Matrix (90-deg ply):\\n", ply_90_deg.Qbar)
print("Transformation Matrix T (90-deg ply):\\n", ply_90_deg.T)

Initializing from a Dictionary

You can load your plies directly from a JSON source.

ply_dict = {
    "plyID": "3",
    "angle": 45.0,
    "material": zg_material,
    "thickness": 0.125
}

ply_45_deg = Ply.fromDict(**ply_dict)
print("Qbar Matrix (45-deg ply):\\n", ply_45_deg.Qbar)

Commands

The package provides a command-line interface entry point. After installing, you can run the main application using:

ply

(Currently, this serves as an entry point defined in ply.main:main)