DJEBBOUR MOHAMED ABDELHADIHICHOUR ABDERRHMANEOUARI MOHAMED AMINE2026-10-042026-10-042026https://dspace.univ-temouchent.edu.dz/handle/123456789/7718The recent development of the global plastics industry, particularly polymer materials, has motivated this study focused on the energetic aspect of the behavior of High-Density Polyethylene (HDPE). The objective is to analyze the combined influence of testing conditions and stress amplitude on the evolution of dissipated energy and fatigue life expressed in the number of cycles, in order to optimize these parameters, reduce energy losses, and increase testing efficiency. The testing frequency and the applied stress amplitude were defined as input variables, while the number of cycles and dissipated energy were considered output variables. Loading– unloading loops were analyzed to extract the dissipated energy values associated with each experimental condition. Based on the datasets obtained for different amplitudes, mathematical models were developed to simultaneously estimate dissipated energy and the corresponding number of cycles. The results show that stress amplitude has the most significant effect on the cyclic behavior of HDPE, followed by testing frequency. The study of interactions between these factors made it possible to identify optimal combinations leading to a target number of cycles, thus providing opportunities to improve fatigue resistance and optimize testing protocols. These findings pave the way for practical recommendations regarding the design, sizing, and maintenance of HDPE structures.frPolymersHDPEdissipated energystressdamagefatiguefatigue life.Thesis