Mechanical Behaviour of HDPE Agricultural Nets Under Accelerated Aging: Experimental Tensile and Structural Analysis

Agricultural nets are increasingly used for crop protection, although their long-term outdoor mechanical durability remains poorly investigated. This study evaluates the tensile behavior of five HDPE nets (anti-rain and anti-insect) subjected to accelerated ageing in an artificial chamber for 2, 4, 8, and 12 weeks (approximately corresponding to 3–18 months of natural exposure). Unidirectional tensile tests were performed in both weft (machine) and warp (transversal) directions to determine Maximum Strength (Fm), Tensile Stress at Maximum Strength (Sm), and Elongation at Maximum Strength (A). The results showed pronounced mechanical anisotropy, with differences in elongation between test directions reaching up to 47%, depending on the net structure and thread arrangement. Accelerated ageing caused a progressive reduction in both tensile strength and ductility, with strength losses in some cases reaching 40–45% after 12 weeks of exposure. Based on the nets analyzed in this study, anti-rain nets tended to exhibit higher initial strength values but faster degradation rates, whereas anti-insect nets showed lower initial strength values (1200–1500 N) and a comparatively more stable response over time. These results suggest that the durability of agricultural nets is strongly influenced by structural configuration and load direction. From an engineering perspective, mechanical durability can be considered a key parameter when selecting crop-protection systems intended for long-term field applications.