Mullins effect in polyethylene and its dependency on crystal content: A network alteration model

Experimental investigation and modeling attempt on the effects of ultraviolet aging on the fatigue behavior of an LDPE semi-crystalline polymer

“…There are polymers with a large variety of molecular and supramolecular structures, but only two basic macromolecular arrangements can be distinguished: totally amorphous and semi-crystalline structures. Their durability and resistance to environmental factors and operating conditions, such as UV radiation [2,3,4], chemical reagents [5,6,7], heat [8,9,10], mechanical loadings [6,11,12,13], humidity, and contact with microorganisms [14], determine the polymers' useful life and their economic and environmental impact [15]. Different and competing degradation mechanisms were reported depending on environmental and operating conditions [16].…”

“…A semi-empirical low-cycle fatigue-life model was proposed by Yang et al [51] to predict the rate dependence of fatigue life and the effect of ratcheting. Makki et al [13] proposed a unified viscohyperelastic-viscoelastic-viscoplastic constitutive model coupled with an alteration theory and successfully captured the lowcycle behavior of polyethylene with variable crystal content.…”

Automated Generation of Material Laws at Large Strains Using a Genetic Algorithm

“…To this end, kinematic as well as kinetic relations are evaluated with respect to the connected rheological elements representing nonlinear material models at large strains. By limiting the basic structure of the rheological model to a parallel connection, this method has been applied for example by [1], [9], [17] and [21]. The complexity of the rheological models and, thus, the phenomenological effects, will increase, if series connections are additionally considered.…”

Modeling the visco-hyperelastic–viscoplastic behavior of photodegraded semi-crystalline low-density polyethylene films

“…The mechanical behavior of semi-crystalline PE is time dependent and can exhibit quasielastomeric behavior at low crystal content and evolve to show a typical thermoplastic behavior at high crystal content (Ayoub et al, 2011). Under cyclic loading semicrystalline PE exhibit a dissipative behavior characterized by the presence of hysteresis loops accompanied with mechanical properties deterioration (Lin and Argon, 1994;Makki et al, 2017;Qi et al, 2019). With increasing temperature, it is reported that the mechanical response of semicrystalline thermoplastic such as yield stress, initial Young's modulus and strain hardening decrease while ductility increase (Brooks et al, 1998).…”

“…Later, Ahzi et al (2003) and Makradi et al (2005) considered the intermolecular resistance to be a combination of amorphous and crystalline phases. Ayoub et al (2011), Ayoub et al (2010) and Makki et al (2017) improved the modeling capabilities of the approach under olygocyclic loading (strain controlled cyclic loading) by directly incorporating the nonlinear viscosity effects on the elastic part. In both cases, the Arruda and Boyce (1993) eight-chain model was used to describe the stress developed by the network.…”