Publication details
Abstracts and keywords
Technological equipment often induces mechanical damage to biological objects as a result of contact with working elements. The developed methodology involves the application of artificially generated loads (both static and dynamic) to test samples, determination of critical rupture forces, computed tomography scanning, image processing, and evaluation of the degree of internal damage.
External mechanical loading of the biological objects was carried out using a standard testing machine (Zwick/Roell Z2.5) and a custom-designed impact testing rig. In the initial stage, the critical force at which complete deformation of the biological object occurred was determined. Subsequent loading scenarios employed specific percentages of this critical force to apply controlled stress to the biological samples.
As the biological object, seeds of the agricultural crop Zea mays (corn hybrid P9074) were selected, with an initial moisture content of 15%.
Tomography of the pre-damaged samples (subjected to both static and dynamic loading) was performed using a Zeiss Xradia 510 Versa 3D scanner, equipped with a 4× objective lens suitable for sample sizes ranging from 2 to 50 mm. The maximum 3D field of view (WFM) was 6(10) mm, with a voxel size in the range of 0.7–3 µm. The average scanning time per sample under the specified parameters was approximately 3.4 hours.
The output of this stage was a dataset of 2D images (10 uniformly spaced horizontal and 10 vertical cross-sections) and a 3D reconstruction of the internal structure. To enhance the visibility of internal defects (such as cracks), image color inversion was applied.
Table 1 presents the results of tomography analysis for selected corn seed samples.
Table 1. Summary of external loading conditions and damage type for maize seed samples
Experiment No. 1 : External Load (% of Critical): 0%; Load Value, N: 0; Load Type: None; File name: Sample_1 Experiment No. 2 : External Load (% of Critical): 30%; Load Value, N: 100; Load Type: Static; File name: Sample_2 Experiment No. 3 : External Load (% of Critical): 90%; Load Value, N: 500; Load Type: Static; File name: Sample_3 Experiment No. 4 : External Load (% of Critical): 30%; Load Value, N: 100; Load Type: Dynamic; File name: Sample_4 Experiment No. 5 : External Load (% of Critical): 90%; Load Value, N: 500; Load Type: Dynamic; File name: Sample_5
Post-processing of the tomography images was performed using the Monte Carlo method, enabling the calculation of micro-damage coefficients. The method is based on grid point sampling to detect the presence of geometrical objects (i.e., damaged regions) within the volume. This approach allowed the derivation of quantitative relationships between the applied load parameters and the extent of internal micro-damage.
Additional information
Project information
