3pc-laminate

3pc-laminate is a Python library used to define a composite laminate and compute its properties based on classical lamination theory. It provides a Laminate class to define the stacking sequence of plies and compute its overall behavior, built upon the Ply class (provided by the 3pc-ply package).

Installation

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

pip install 3pc-laminate 3pc-ply 3pc-material

API Reference

Laminate Class

The primary component of this package is the Laminate class, which holds a stacking sequence of plies and dynamically calculates transformed stiffness matrices and engineering constants.

from laminate.laminate import Laminate

Required Parameters

When initializing Laminate directly, the following parameters are required:

• lamID (str): Laminate identifier.
• stacking_sequence (list): List of Ply objects starting from the bottom of the laminate (at -thickness/2.0) and ending at the top of the laminate (at +thickness/2.0), i.e., full stacking sequence.
• offset (str or float): Reference plane offset from midplane. Can be "top", "bottom", "mid", or a float value.

Calculated Properties

The class automatically calculates the following properties lazily:

• thickness: Total laminate thickness.
• rho: Average laminate density using rule of mixtures.
• z: List of z-coordinates for each ply interface relative to the reference plane.
• A: Extensional stiffness matrix of the laminate.
• B: Coupling stiffness matrix of the laminate.
• D: Bending stiffness matrix of the laminate.
• ABD: Full stiffness matrix in the form of [[A, B], [B, D]].
• A44, A45, A55: Transverse shear stiffnesses.
• gamma, delta: Laminate properties measuring the effects of D16 and D26 respectively.
• Ex, Ey, Gxy, vxy, vyx: In-plane engineering constants.
• Efx, Efy, Gfxy, vfxy, vfyx: Flexural engineering constants.
• alphax, alphay, alphaxy: Thermal expansion coefficients.
• betax, betay, betaxy: Hygral (moisture) expansion coefficients.

Methods

Laminate.fromDict(**kwargs)

Initializes a Laminate 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 a laminate using plies and materials.

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

# 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,
    rho=1.5
)

# Define plies
ply_0 = Ply(plyID="1", angle=0.0, material=zg_material, thickness=0.125)
ply_90 = Ply(plyID="2", angle=90.0, material=zg_material, thickness=0.125)

# Define laminate (0/90)s
lam = Laminate(
    lamID="lam_01", 
    stacking_sequence=[ply_0, ply_90, ply_90, ply_0],
    offset="mid"
)

# Access Computed Properties
print("A Matrix:\\n", lam.A)
print("Effective Ex:", lam.Ex)
print("Effective Ey:", lam.Ey)

Initializing from a Dictionary

You can load your laminate directly from a dictionary.

lam_dict = {
    "lamID": "lam_02",
    "stacking_sequence": [ply_0, ply_90],
    "offset": "bottom"
}

lam_2 = Laminate.fromDict(**lam_dict)
print("Total thickness:", lam_2.thickness)

Commands

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

laminate

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