Wieczorska Agata, Hajdukiewicz Grzegorz
Faculty of Marine Engineering, Gdynia Maritime University, Morska St. 81-87, 81-225 Gdynia, Poland.
Materials (Basel). 2024 Dec 19;17(24):6219. doi: 10.3390/ma17246219.
This paper presents the application of Kolmogorov-Sinai (EK-S) metric entropy calculations performed on experimental data sets (relative elongations ε) recorded during static tensile testing of a composite material with carbonisate. The EK-S calculation method makes it possible to represent the dynamics of strain change occurring during the endurance test. The depiction of the change in the dynamics of elongation compared to the course of the tensile curve makes it possible to analyse the strength properties of the tested specimens. The material used for the study is a layered epoxy composite with the addition of carbonisate obtained by pyrolysis from organic waste from MDF (Medium Density Fibreboard) furniture boards. For the tested material, two variants were prepared without the addition of carbonisate (samples designated as I and III) and two variants differing in the percentage of carbonisate: 5% by mass (sample IV) and 7.5% by mass (sample II), with a constant fraction of 0.5 mm. Analyses showed a slight deterioration in the tensile properties of composites containing carbonisate. SEM (Scanning Electron Microscope) studies of the carbonisate samples revealed the presence of cracks, pores and local delamination, which correlates with a reduction in strength parameters. For sample II, the tensile strength (R) was 9.032% lower compared to the base sample I and the tensile strain decreased by 0.098%. For sample IV, a decrease in parameters was also observed compared to base sample III-the strength decreased by 13.29%, and the tensile strain decreased by 10.64%. The results obtained in this study were additionally decided to be analysed using metric entropy calculations, which makes it possible to capture significant qualitative changes occurring in the structure of the tested samples not depending on the results of the static tensile test. In the context of epoxy composites with the addition of carbonisate, this analysis can contribute to a better understanding of the influence of the carbonisate obtained in the pyrolysis process on the structure of the composite and its performance properties.
本文介绍了对含碳酸盐的复合材料在静态拉伸试验过程中记录的实验数据集（相对伸长率ε）进行柯尔莫哥洛夫-西奈（K-S）度量熵计算的应用。K-S计算方法能够呈现耐久性试验期间发生的应变变化动态。与拉伸曲线过程相比，伸长率动态变化的描绘使得分析测试样本的强度特性成为可能。用于该研究的材料是一种层状环氧复合材料，添加了通过热解从MDF（中密度纤维板）家具板的有机废料中获得的碳酸盐。对于测试材料，制备了两种未添加碳酸盐的变体（样品标记为I和III）以及两种碳酸盐百分比不同的变体：5质量%（样品IV）和7.5质量%（样品II），恒定分数为0.5毫米。分析表明含碳酸盐复合材料的拉伸性能略有下降。碳酸盐样品的扫描电子显微镜（SEM）研究揭示了裂纹、孔隙和局部分层的存在，这与强度参数的降低相关。对于样品II，与基础样品I相比，拉伸强度（R）降低了9.032%，拉伸应变降低了0.098%。与基础样品III相比，样品IV的参数也出现了下降——强度降低了13.29%，拉伸应变降低了10.64%。本研究中获得的结果还决定使用度量熵计算进行分析，这使得能够捕捉测试样本结构中发生的显著定性变化，而不依赖于静态拉伸试验的结果。在添加了碳酸盐的环氧复合材料的背景下，这种分析有助于更好地理解热解过程中获得的碳酸盐对复合材料结构及其性能特性的影响。
