Curved Rod Voxel Model

A MATLAB–Abaqus workflow for curved-rod voxel lattice generation, dual-scale 2x2x2 / 4x4x4 compression simulation, automatic force–displacement and stress–strain extraction, and STL preparation for 3D printing.

This repository is the original voxel-based curved-rod lattice workflow. It is kept as a complete reference pipeline for voxel lattice generation, compact Abaqus .inp export, automated compression simulation, and printing-oriented STL export.

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Version

Current version: V2.0 Dual-scale simulation and 3D-printing workflow

Main updates:

• Separated 2x2x2 and 4x4x4 workflows
• Added STL export for Bambu Studio / 3D printing
• Added compact Abaqus .inp exporter
• Added separated Output, STL, Abaqus_Work, and Results folders
• Added practical 3D printing notes

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Main Workflow

curved-X topology
→ voxel lattice generation
→ 2x2x2 / 4x4x4 voxel repetition
→ compact Abaqus INP export
→ Abaqus compression simulation
→ force-displacement and stress-strain curves
→ STL export for 3D printing

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Repository Structure

Curved_Rod_Voxel_Model/
├─ 2x2x2/
│  ├─ batch_generate_curved_x.m
│  ├─ batch_repeat222_and_export_inp.m
│  ├─ batch_export_mat_voxel_to_stl_222.m
│  ├─ export_mat_voxel_to_abaqus_inp.m
│  ├─ export_one_mat_to_stl.m
│  ├─ export_voxel_to_stl_binary.m
│  ├─ GenerateVoxel.m
│  ├─ write_curved_x_topology.m
│  ├─ save_sample_mat.m
│  ├─ save_repeat222_mat.m
│  ├─ abaqus_batch_run_all.py
│  ├─ postprocess_summary_and_plots.py
│  ├─ batch_curved_x/
│  ├─ Output/
│  ├─ STL/
│  ├─ Abaqus_Work/
│  └─ Results/
│
├─ 4x4x4/
│  ├─ batch_generate_curved_x.m
│  ├─ batch_repeat444_and_export_inp.m
│  ├─ batch_export_mat_voxel_to_stl_444.m
│  ├─ export_mat_voxel_to_abaqus_inp.m
│  ├─ export_one_mat_to_stl.m
│  ├─ export_voxel_to_stl_binary.m
│  ├─ GenerateVoxel.m
│  ├─ write_curved_x_topology.m
│  ├─ save_sample_mat.m
│  ├─ save_repeat444_mat.m
│  ├─ abaqus_batch_run_all.py
│  ├─ postprocess_summary_and_plots.py
│  ├─ batch_curved_x/
│  ├─ Output/
│  ├─ STL/
│  ├─ Abaqus_Work/
│  └─ Results/
│
├─ README.md
└─ 3D_print_note.txt

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Quick Start

1. Generate voxel models in MATLAB

For 2x2x2:

cd('D:\Simulation\Curved_Rod_Voxel_Model\2x2x2')

batch_generate_curved_x
batch_repeat222_and_export_inp
batch_export_mat_voxel_to_stl_222

For 4x4x4:

cd('D:\Simulation\Curved_Rod_Voxel_Model\4x4x4')

batch_generate_curved_x
batch_repeat444_and_export_inp
batch_export_mat_voxel_to_stl_444

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2. Run Abaqus compression simulation

For 2x2x2:

Set-Location "D:\Simulation\Curved_Rod_Voxel_Model\2x2x2"
abaqus cae noGUI=abaqus_batch_run_all.py

For 4x4x4:

Set-Location "D:\Simulation\Curved_Rod_Voxel_Model\4x4x4"
abaqus cae noGUI=abaqus_batch_run_all.py

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3. Run Python postprocessing

For 2x2x2:

Set-Location "D:\Simulation\Curved_Rod_Voxel_Model\2x2x2"
python postprocess_summary_and_plots.py

For 4x4x4:

Set-Location "D:\Simulation\Curved_Rod_Voxel_Model\4x4x4"
python postprocess_summary_and_plots.py

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Output Files

Folder	Description
batch_curved_x/mat/	Base single-cell voxel .mat samples
batch_curved_x/topology/	Curved-X topology text files
batch_curved_x/preview/	Preview images for selected samples
batch_curved_x/2x2x2_mat/	Repeated 2x2x2 voxel .mat files
batch_curved_x/4x4x4_mat/	Repeated 4x4x4 voxel .mat files
Output/	Abaqus .inp files
STL/	STL files for 3D printing
Abaqus_Work/	Abaqus job folders and ODB files
Results/	Curve CSV files, summary metrics, and figures

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Main Scripts

Script	Function
batch_generate_curved_x.m	Generates random curved-X voxel samples
GenerateVoxel.m	Converts topology definitions into voxel grids
write_curved_x_topology.m	Writes curved-X topology files
save_sample_mat.m	Saves accepted base samples
batch_repeat222_and_export_inp.m	Builds 2x2x2 repeated specimens and exports Abaqus .inp files
batch_repeat444_and_export_inp.m	Builds 4x4x4 repeated specimens and exports Abaqus .inp files
export_mat_voxel_to_abaqus_inp.m	Converts repeated voxel .mat files into compact Abaqus mesh-only .inp files
batch_export_mat_voxel_to_stl_222.m	Exports 2x2x2 STL files
batch_export_mat_voxel_to_stl_444.m	Exports 4x4x4 STL files
abaqus_batch_run_all.py	Runs Abaqus compression jobs and extracts curve CSV files
postprocess_summary_and_plots.py	Generates summary metrics and plots

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Key Parameters

MATLAB generation

Modify these parameters in batch_generate_curved_x.m if needed:

targetN
nVoxel
radiusMin / radiusMax
bendMin / bendMax
densityMin / densityMax
desiredWorkers

For practical 3D printing, a thicker rod range is recommended:

radiusMin = 0.075;   % approximately 3.0 mm rod diameter
radiusMax = 0.100;   % approximately 4.0 mm rod diameter

Original smaller simulation setting:

radiusMin = 0.032;
radiusMax = 0.041;

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Repetition scale

% 2x2x2 branch
repeatN = [2 2 2];

% 4x4x4 branch
repeatN = [4 4 4];

Default voxel size:

voxelSize = [0.25 0.25 0.25];

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Abaqus compression settings

Default compression setup:

2x2x2: H0 = 40 mm, compression displacement = -8 mm
4x4x4: H0 = 80 mm, compression displacement = -16 mm

Recommended Abaqus testing setting:

MAX_CASES = 1

Run all cases after validation:

MAX_CASES = None

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Postprocessing Outputs

postprocess_summary_and_plots.py reads curve CSV files in Results/ and generates:

summary_metrics.csv
correlation_matrix.csv
top10_by_energy_absorption.csv
top10_by_SEA.csv
figures/

Typical curve outputs include:

*_force_displacement.csv
*_stress_strain.csv
*_all_response.csv

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3D Printing Notes

For STL slicing and Bambu Studio settings, see:

3D_print_note.txt

Recommended initial workflow:

1) Generate STL files from MATLAB
2) Import one STL file into Bambu Studio
3) Use TPU as the main material
4) Use PVA support if needed
5) Start with 2x2x2 specimens for faster printing tests

For practical TPU printing, the original 1.3–1.6 mm rod diameter may be too thin. A thicker 3–4 mm rod diameter range is recommended for initial fabrication tests.

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Notes

• 2x2x2 is recommended for fast simulation and printing validation.
• 4x4x4 is used for larger-scale mechanical simulation and dataset generation.
• Keep Abaqus work and scratch folders on a large disk rather than the system drive.
• This voxel branch is useful as a complete reference workflow for voxel-based curved-rod lattice generation.
• For faster solid-strut stress contour generation, use the newer CurviStrut-Lattice tube-solid workflow.

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Version History

V1.0

Initial MATLAB–Abaqus workflow for curved-rod voxel lattice generation, 4x4x4 specimen export, Abaqus compression simulation, and automatic curve extraction.

V2.0

Dual-scale simulation and 3D-printing workflow.

Main updates:

• Added separated 2x2x2 and 4x4x4 workflows
• Added STL export for 3D printing
• Added compact Abaqus .inp export
• Added separated Output, STL, Abaqus_Work, and Results folders
• Added practical 3D printing note

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License

This project is released under the MIT License.