A Comparison Between Uniaxial and Biaxial Tensile Properties of Biocomposites Films Using of 3D-Digital Image Technique

The choice of the suitable characterization method plays a crucial role in accurately assessing the mechanical behavior of materials under specific stress conditions. Plastic films used in bagging and packaging applications commonly experience a biaxial stress state during their operational use necessitating characterization under biaxial stress rather than uniaxial stress. This study focuses on investigating the biaxial behavior of Polylactic acid (PLA) films and biocomposites, specifically filled with 1, 2 and 5 weight percent of date palm leaf filler (DPLF) with a thickness about 50 to 120 µm. To analyze the biaxial properties, the films underwent pneumatic bulge testing, which provided insights into their biaxial behavior. Additionally, all films were characterized using tensile tests conducted along their machine direction (MD) and transverse direction (TD) for a comparative with the biaxial behavior. The implementation of the 3D- Digital image correlation method (3D-DIC) in both test methods enabled accurate strain measurement, in-depth analysis of strain field evolution throughout the tests, and evaluation the development of strain concentration development during the experiments.