The correlation between the mixed-mode oligo-cyclic loading induced mechanical and microstructure changes in HDPE

Two grades of HDPE (one is for PE-100 pipeline application and one blow molding) were processed to vary their crystallinity molecular topology in order investigate understand the microstructural origin seismic performance materials. For a given grade, quenched sample exhibits lower crystallinity, thinner crystallites, higher density entanglement/tie molecules compared isothermal one. The samples are submitted mixed-mode, oligo (plastic)-cyclic tensile deformation (that simulates seism) with applied maximum strain below or at onset necking propagation. changes numerous macroscopic mechanical metrics increasing cycles monitored (e.g. stress strain, residual zero stress, secant modulus, hysteresis loop area). These not only depend on imposed cyclic but also microstructure HDPE. A physical scenario proposed describe during explicate macro-micro correlations. Moreover, post-cyclic (reloading) curve can return original rapidly each sample, this phenomenon indicates neglecting effect following further loading path. It found that material designed shows limited variation between initial toughness, indicating pre-loaded materials require nearly same energy rupture as pristine ones. This evidence has good resistance against damage induced by events.