Accompanying data for the paper "Crack branching at low tip speeds: spilling the T"

Links

• isCitedBy publication-article https://doi.org/10.46298/jtcam.10172
• isSupplementedBy software https://archive.softwareheritage.org/swh:1:dir:73fae3c4e4fce0f9a2c36a7ccf3a7be7c229c5ca;origin=https://github.com/jrethore/ufreckles;visit=swh:1:snp:9c0d967db98cef7f2b5d1dca641d392f75794b80;anchor=swh:1:rev:c83ced7bf43f3bd717f85c82a39c8cce2a5515db
• isSupplementedBy software https://zenodo.org/record/1433776

Language

• English

License

• Creative Commons Attribution 4.0

Contributions

• Elie Eid contributed to the experiments, their analysis, the numerical simulations and the writing of the paper.
• Rian Seghir contributed to the experiments and the fullfield measurements. He also contributed to the writing of the paper.
• Julien Réthoré contributed to the experiments and to the writing of the paper.

Data collection: period and details

• Data have been collected during July 2021

Funding sources

• Connect Talent IDS project funded by Région Pays de la Loire, Nantes Métropole and Ecole Centrale de Nantes with the additional support of of European Union.
• French Research National Agency programme through grant ANR-16-CE30-0007-01

Data structure and information

• Four SCDC (Single Crack Direct Compression) specimens are dynamically loaded via an impact on the edge perpendicular to the notch.
• Specimens are mounted on a waveguide to ensure proper compressive wave entering the specimen and to hold the sample while keeping all other boundaries free.
• The impact induces a compressive wave; however, the presence of the hole creates a tensile zone sideways opening thus the notch and enabling the fracture initiation.
• Due to the absence of an impedance at the right-hand side boundary, stress-waves are fully reflected from the right-hand side boundary and deliver new loading-unloading conditions of the crack-tip modifying its advancement eventually leading to branching.
• Samples are laser-cut from a commercial PolyMethyl Methacrylate (PMMA) manufactured by Arkema. The pre-crack's width matches the beam's, ie. 200um. A synthetic speckle pattern is laser-engraved onto the sample surface (useful for ensuring quality and reproducibility of the pattern for the application of the DIC procedure).
• All images are captured using the High-spatial Resolution and Ultra-high speed (HR-UHS) Cordin camera Model 580 at 400 kfps with a resolution of 3296 x 2472 pixels. Field of view is 154.25mm x 115.69mm leading to a pixel size of 0.0468mm.

Ufreckles is used to perform FE-based DIC using T3P1 linear triangular elements and a Tikhonov regularisation (over 3 elements). Eventually, Linear Elastic Fracture Mechanics (LEFM) parameters are obtained post-projecting displacement fields on Williams' series using Ufreckles.

• https://zenodo.org/badge/DOI/10.5281/zenodo.1433776
• https://archive.softwareheritage.org/badge/swh:1:dir:73fae3c4e4fce0f9a2c36a7ccf3a7be7c229c5ca/

Complete analysis of the data can be found in [Eid, E., Seghir, R., & Réthoré, J. (2023). Crack branching at low tip speeds: spilling the T. Journal of Theoretical, Computational and Applied Mechanics.]

All test directories contain:

Data

• raw images: in /images/ folder in 16bit .tiff format
• the timeline: at root (time.txt) in µs
• a distortion model: at root (Distortion.mat) containing camera distortion modes and amplitudes for each camera sensor
• a mesh: at root (mesh_crack_conform.vtk) for FE-based DIC
• VTK result fields: in /Results/VTK/ containing experimental DIC mesh, nodal displacement, velocity and accelerations fields and elementary strain and strain-rate fields for each frame
• Fracture parameters: in /Results/VTK/LEFM.txt containing the identified LEFM parameters (for the main crack propagation from initiation to branching frames)

Matlab Codes to produce results (working with Ufreckles)

• MultiSensor_DIC_script.m: in /Codes/ is the main script to run DIC
• Shape functions: in /Codes/shape_functions/ containing Zernike polynomial shape functions and deconvolution algorithm to get effective displacement from total displacement knowing camera distortions

One directory per tested specimen:

• T3DE: impacted at a projectile velocity of 31.8 m/s
• TAF1: impacted at a projectile velocity of 30.5 m/s
• TAF2: impacted at a projectile velocity of 22 m/s
• THOM: impacted at a projectile velocity of 22 m/s