Metadata-Version: 2.4
Name: 3pc-sandbend
Version: 1.0.0
Summary: Python library for bending analysis of shear deformable anisotropic sandwich plates under transverse loads, hygrothermal, and mechanical loads.
Author: Omprakash Seresta
Author-email: oseresta@gmail.com
License: MIT
Project-URL: Blog, https://3pcomposites.com/blogs-1/f/3pcsolver006-deflection-analysis-of-sandwich-panels
Project-URL: Analysis Tools, https://3pcomposites.com/analysis-tools
Project-URL: Documentation, https://drive.google.com/drive/folders/1jDb-P5BOgJ-moVU20B7D8oVeHjHLAHTm
Keywords: sandwich-plates bending-analysis composites anisotropic aerospace-engineering mechanics fsdt clt transverse-loads hygrothermal
Classifier: Programming Language :: Python :: 3
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Requires-Python: >=3.6
Description-Content-Type: text/markdown
License-File: LICENSE
Requires-Dist: 3pc-material
Requires-Dist: 3pc-ply
Requires-Dist: 3pc-laminate
Requires-Dist: 3pc-panel
Requires-Dist: 3pc-sandwich
Requires-Dist: 3pc-loads
Requires-Dist: 3pc-utils
Requires-Dist: numpy
Requires-Dist: scipy
Dynamic: author
Dynamic: author-email
Dynamic: classifier
Dynamic: description
Dynamic: description-content-type
Dynamic: keywords
Dynamic: license
Dynamic: license-file
Dynamic: project-url
Dynamic: requires-dist
Dynamic: requires-python
Dynamic: summary

# 3pc-sandbend

`3pc-sandbend` is a Python library for bending analysis of shear deformable anisotropic sandwich plates under transverse loads, hygrothermal, and mechanical loads. It provides a `Sandbend` class to calculate reference surface displacements, rotations, strains, curvatures, and transverse shear strains across a user-specified coordinate grid.

## Installation

Use the package manager [pip](https://pip.pypa.io/en/stable/) to install `3pc-sandbend`. Since the package and its dependencies are available on PyPI, you can install them directly:

```bash
pip install 3pc-sandbend
```

## API Reference

### `Sandbend` Class

The primary component of this package is the `Sandbend` class, which takes a panel, a load case, and coordinates/Fourier-expansion parameters to solve the sandwich bending governing equations.

```python
from sandbend.sandbend import Sandbend
```

#### Required Parameters

When initializing `Sandbend`, the following parameters are required:

*   **`panel`** *(Panel)*: An instance of the `Panel` class (from `3pc-panel`) containing the face sheet laminates and sandwich core definition.
*   **`loads`** *(Loads)*: An instance of the `Loads` class (from `3pc-loads`) containing the load case and environmental conditions.
*   **`number_of_terms`** *(int)*: Number of terms in the double Fourier series expansion.
*   **`number_of_points_x`** *(int)*: Number of points along x-direction to calculate values.
*   **`number_of_points_y`** *(int)*: Number of points along y-direction to calculate values.

#### Calculated Properties

The class calculates the following properties:

*   **`pairs`**: List of pairs `(i, j)` for all `i, j = 1, 2, ..., M`, where `M` is the number of terms.
*   **`K33`**: Load-dependent part of the stiffness term K33 for all pairs.
*   **`Pmn`**, **`PFull`**: Load coefficient arrays.
*   **`u`**, **`v`**, **`w`**: Reference surface displacement components.
*   **`phix`**, **`phiy`**: Reference surface rotations.
*   **`uloc`**, **`vloc`**, **`wloc`**: Grid point displacements.
*   **`phixloc`**, **`phiyloc`**: Grid point rotations.
*   **`ex0Bloc`**, **`ey0Bloc`**, **`gxy0Bloc`**: Reference surface in-plane strains at grid locations.
*   **`kx0Bloc`**, **`ky0Bloc`**, **`kxy0Bloc`**: Reference curvatures at grid locations.
*   **`gxz0Bloc`**, **`gyz0Bloc`**: Transverse shear strains at grid locations.
*   **`ek0Bloc`**, **`gT0Bloc`**, **`NMBloc`**, **`QBloc`**: Reference strain, thermal strain, force/moment resultants, and shear force resultants at each grid location.
*   **`coeff`**: Calculated displacement and rotation coefficients.

### Methods

#### `Sandbend.fromDict(**kwargs)`

Initializes a `Sandbend` instance using a dictionary of keyword arguments.

---

## Usage Examples

### Basic Initialization

Below is an example of performing a sandwich bending analysis.

```python
from panel.panel import Panel
from loads.loads import Loads
from sandbend.sandbend import Sandbend

# Assuming pnl (Panel) and ld (Loads) are already defined
sb = Sandbend(
    panel=pnl,
    loads=ld,
    number_of_terms=13,
    number_of_points_x=5,
    number_of_points_y=5
)

# Access calculated results
print("Grid displacements (wloc):", sb.wloc)
print("Strains & curvatures (ek0Bloc):", sb.ek0Bloc)
```

## Commands

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

```bash
sandbend input.cfg
```

*(This entry point is defined in `sandbend.__main__:main`)*

### Options

*   **`config`** *(positional)*: Specify the configuration file (`.cfg`) to run the analysis.
*   **`-h, --help`**: Show the help message and exit.
*   **`-v, --version`**: Show the version number.
*   **`-s, --sample`**: Copy example files (materials, plies, cores, laminates, panels, loads, config) to the current directory.

### Configuration File (`sandbend.cfg`)

The `sandbend` command requires a configuration file (typically named `sandbend.cfg`). Below is an example based on `sandbend/examples/example001/sandbend.cfg`:

```ini
[files]
materials = materials.json
plies = plies.json
cores = cores.json
laminates = laminates.json
panels = panels.json
loads = loads.json
output = output.txt

[analysis]
number_of_terms = 13
number_of_points_x = 5
number_of_points_y = 5
```

#### `[files]` Section

This section defines the paths to the required input JSON files and the desired output file:

*   **`materials`**: Path to the materials JSON file. Follows the format expected by [`3pc-material`](https://pypi.org/project/3pc-material/).
*   **`plies`**: Path to the plies JSON file. Follows the format expected by [`3pc-ply`](https://pypi.org/project/3pc-ply/).
*   **`cores`**: Path to the cores JSON file.
*   **`laminates`**: Path to the laminates JSON file. Follows the format expected by [`3pc-laminate`](https://pypi.org/project/3pc-laminate/).
*   **`panels`**: Path to the panels JSON file. Follows the format expected by [`3pc-panel`](https://pypi.org/project/3pc-panel/).
*   **`loads`**: Path to the loads JSON file. Follows the format expected by [`3pc-loads`](https://pypi.org/project/3pc-loads/).
*   **`output`**: Path to the text file where the sandwich bending analysis results will be written.

#### `[analysis]` Section

This section specifies the analysis settings:

*   **`number_of_terms`**: Number of terms in the double Fourier series expansion.
*   **`number_of_points_x`**: Number of grid points along the x-direction.
*   **`number_of_points_y`**: Number of grid points along the y-direction.

## Citation

If you use this library in your research or work, please cite it as follows:

**APA Format:**
> Seresta, O. (2026). *3pc-sandbend: Python library for bending analysis of shear deformable anisotropic sandwich plates under transverse loads, hygrothermal, and mechanical loads*. PyPI. https://pypi.org/project/3pc-sandbend/

**BibTeX:**
```bibtex
@software{3pc_sandbend,
  author = {Seresta, Omprakash},
  title = {3pc-sandbend: Python library for bending analysis of shear deformable anisotropic sandwich plates under transverse loads, hygrothermal, and mechanical loads},
  year = {2026},
  url = {https://pypi.org/project/3pc-sandbend/}
}
```
