May 12, 2026
Version 2
Standardized protocol for tensile test on palm leaflets V.2
- Paul Cathelineau1,
- Louise Brousseau1,
- Julie Bossu2,
- Romain Lehnebach3
- 1IRD;
- 2CNRS;
- 3CIRAD
Protocol Citation: Paul Cathelineau, Louise Brousseau, Julie Bossu, Romain Lehnebach 2026. Standardized protocol for tensile test on palm leaflets. protocols.io https://dx.doi.org/10.17504/protocols.io.ewov124rpgr2/v2Version created by Paul Cathelineau
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: May 11, 2026
Last Modified: May 12, 2026
Protocol Integer ID: 316816
Keywords: DOPAMICS, Biomechanics, Digital Image Correlation, Modulus of elasticity, Palms, Leaflet, Strain, Tensile test, Plant material, biomechanical properties of palm leaflet, palm leaflet, assessing biomechanical property, standardized protocol for tensile test, tensile test, digital image correlation, dopamics research program, reproducibility of the research, funded dopamics research program
Funders Acknowledgements:
DOPAMICS
Grant ID: 101039272
Disclaimer
Funded by the European Union (ERC, DOPAMICS, grant no. 101039272). Views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency (ERCEA). Neither the European Union nor the granting authority can be held responsible for them.
Abstract
We describe the protocol developed as part of the ERC-funded DOPAMICS research program for assessing biomechanical properties of palm leaflets via Digital Image Correlation (DIC).
This protocol is made open access under the Creative Commons Attribution License (CC-BY). It details the sampling strategy and steps, and the material needed with the aim to encourage future reuses of this protocol for the same or similar research purposes, and to improve the reproducibility of the research conducted. Reuse of this protocol must credit the authors and mention its DOI and download link.
Materials
Preparation materials :
- Scalpel handle N°4 + Feather surgical blade N°24
- Stainless steel template 100x10x10 mm
- Digital calliper Mitutoyo CD-20GM
- Precision scale Sartorius
- Mitutoyo Digital indicator ID-H0530 + Mitutoyo Digimatic interface DMX-1 + Smartlux 232key Pro software
- Vacuum sealer + seal bags
- Oven
- Plant press
- zip-lock plastic bags
- Large (bullet) tip permanent marker (to write on plastic bags)
- Pilot V-ball, rollerball pen 0.7
- White spray paint
DIC materials:
- Camera Basler acA5472-17um
Before start
- Make sure that all samples from the field aren't damaged.
- Make sure that all samples are identified with a unique ID.
Foreword : Sample conditioning
- Wet leaflets were vacuum sealed to preserve their water content.
- If mould develops inside the vacuum-sealed bag, immediately clean the leaflets with 70% ethanol using a cloth and proceed to the drying step (2).
Drying
- Remove the leaflets from the vacuum-sealed bag and make sure that all samples are identified
- Place the leaflets in the plant press, spacing each layer with newspaper sheets. Secure the entire assembly firmly, either using straps for a traditional herbarium press or threaded rods with nuts.
- Put the plant press in an oven at 60°c during 24h.
Sample preparation and measurement
- Cut out the leaflet samples using a steel template (100x10 mm) and a scalpel
- Write the unique ID on the samples
- Weight the samples and report it into your dataset
- Measure three different thickness points using a digital calliper, calculate the mean thickness and report it into your dataset
- Measure the width of the sample using a digital caliper (take the largest width by measuring the width over a large area)
Fig 1. Measure of the width on a wide surface of the sample
- Lightly speckle the samples with a spray of white paint.
Fig 2. Light speckling on six samples
- Let the sample dry
- Using a black pen, mark two points at each longitudinal end of the samples, 25 mm from their center.
Tensile test
- Make sure that the camera's distance and focus are optimal. Position a lamp to illuminate the test area.
Fig 3. Set up of tensile test, camera, tensile bench and light
- Place the sample between the jaws (jaws should be 60 mm apart)
- Run the code and follow the instructions, as explained here : https://github.com/paulcathelineau/CodeMts
- Parameters :
- Exposure time : 15000 μs
- Image width : 800 px
- Image height : 3660 px
- Frame rate : 5 fps
- In parallel, run the tensile bench's software and follow the steps of the previous code to synchronize data (you may have to adapt some part of the code, if you don't use the SyntX software)
- Parameters :
- Preload : 5N
- Load speed : 1mm/min
- Rupture detection : delta on Force +/- 5N
- Select the Region of Interest between the two marked points :
Fig 4. Selection of the Region of Interest between the two marked points (25mm apart from sample center)
- Tensile test are classified depending on rupture :
- Rupture at the jaws => Jaws
Fig 5. Rupture at the jaws
- Vertical rupture => Length
Fig 6. Rupture along the sample length
- Transversal rupture=> Yes
Fig 7. Transversal rupture
The remaining leaflet samples are stored in plastic bags for further analyses
Results
- A linear regression is performed within the strain range of 0.05% to 0.25% to calculate Young's modulus. The result can be seen in "MOE_0.05_0.25.png" and detailed in "linear_regression_results.txt".
Fig 8. Linear regression within the strain range 0.05% to 0.25% used to compute Young's modulus.
- The overall strain behavior is shown in "strain_fields_mean_values.png".
Fig.9, Heatmap of the strain behaviour within the x and y axis
- Processed data are available in "results/strain_MFS.csv", while the raw data are stored in the other CSV files.
- Both raw and processed images are located in the "img" folder.