3pc-sandwich

3pc-sandwich is a Python library used to define a composite sandwich panel and compute its properties. It provides a Sandwich class to define the structural characteristics of sandwich panels (incorporating a core, top facesheet, bottom facesheet, geometry, and boundary conditions). It leverages the Panel class from 3pc-panel and the Laminate class from 3pc-laminate.

Installation

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

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

API Reference

Sandwich Class

The primary component of this package is the Sandwich class, which holds geometric, material, laminate stack, and boundary condition info for a sandwich panel, and computes its overall characteristics.

from sandwich.sandwich import Sandwich

Required Parameters

When initializing Sandwich directly, the following parameters are required:

• panelID (str): Sandwich panel identifier.
• length (float): Sandwich panel length along the x-direction.
• width (float): Sandwich panel width along the y-direction.
• bottom_laminate (Laminate): The Laminate object representing the bottom facesheet of the sandwich panel.
• core (Ply): A Ply object representing the sandwich panel core.
• top_laminate (Laminate): The Laminate object representing the top facesheet of the sandwich panel.
• boundary_condition (str): Boundary condition of the panel. For example, "SSSS" represents simply supported on all four sides.

Calculated Properties

The class automatically calculates the following properties:

• lamID: Laminate ID of the full laminate of the sandwich, structured as bottom_laminateID_coreID_top_laminateID.
• laminate: A Laminate object of the combined sandwich panel (bottom laminate + core + top laminate), with offset set to "middle".
• panel: A Panel object representing the sandwich panel structural system.
• core_index: The index of the core layer in the combined laminate's stacking sequence.

Usage Examples

Basic Initialization

Below is an example of defining a sandwich panel using materials, plies, laminates, and the Sandwich class.

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

# Define material properties
face_material = Orthotropic(
    matID="face_mat", E1=181.0, E2=10.3, G12=7.17, G13=7.17, G23=7.17, v12=0.28, rho=1.5
)
core_material = Orthotropic(
    matID="core_mat", E1=0.23, E2=0.23, G12=0.08, G13=0.08, G23=0.08, v12=0.25, rho=0.1
)

# Define plies for facesheets and the core
ply_face = Ply(plyID="face_ply", angle=0.0, material=face_material, thickness=0.125)
ply_core = Ply(plyID="core_ply", angle=0.0, material=core_material, thickness=1.0)

# Define face laminates
bottom_lam = Laminate(
    lamID="bottom_lam", stacking_sequence=[ply_face, ply_face], offset="mid"
)
top_lam = Laminate(
    lamID="top_lam", stacking_sequence=[ply_face, ply_face], offset="mid"
)

# Define sandwich panel
sandwich_panel = Sandwich(
    panelID="sandwich_01",
    length=6.0,
    width=6.0,
    bottom_laminate=bottom_lam,
    core=ply_core,
    top_laminate=top_lam,
    boundary_condition="SSSS"
)

# Access computed properties
print("Full Stacking Sequence:", sandwich_panel.laminate.stacking_sequence)
print("Combined Laminate ID:", sandwich_panel.lamID)
print("Core Ply Index:", sandwich_panel.core_index)
print("Panel Length:", sandwich_panel.panel.length)

Commands

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

sandwich

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