A large‐strain intrinsic default‐based fracture criterion for polymers: assessment in biaxial loading and application to ageing

Abstract

In this contribution, we attempt to give a general methodology allowing the fracture prediction of polymers under biaxial monotonic loading. Using the intrinsic defect concept, we assume that fracture at a macroscopic level is the consequence of the presence of defects at lower scales. We also assume that the fracture is governed by a macroscopic parameter, the strain energy release rate or the J‐integral. Intrinsic defect size, constitutive response and fracture toughness being the criterion inputs; the principal stretches at break can be therefore estimated for any biaxial and monotonic loading path. The proposed methodology includes the estimation of the J‐integral for any biaxial loading using a unified expression of this parameter which is a generalised form of that developed in the literature for uniaxial tension. Using different set of experimental data obtained in our team, the methodology is then successfully applied to various kinds of polymers: a natural rubber, a styrene‐butadiene rubber, a polyurethane, a thermoplastic elastomer and a high‐density polyethylene. We show also that such a methodology can be applied to predict the ageing effects on the stretches at break.

Effect of ionic liquid modified carbon nanotubes on the properties of nitrile butadiene rubber and nitrile butadiene latex nanocomposites

“…18,19 Therefore, the connection between MWCNTs was weakened at high temperatures due to the potential resistance of ILs, resulting in thermal weight loss. 20 These were also evidenced in the DTG curves in Figure 3b. The modification of MWCNT by IL was proved to be successful.…”

“…At the same time, the high temperature promotes the movement of IL macromolecules, which leads to the weakening of the connection between MWCNTs and causes the thermal weight loss of MWCNTs after the addition of IL 18,19 . Therefore, the connection between MWCNTs was weakened at high temperatures due to the potential resistance of ILs, resulting in thermal weight loss 20 . These were also evidenced in the DTG curves in Figure 3b.…”

Physics and chemistry-based constitutive framework for thermo-chemically aged elastomer using phase-field approach

“…Volokh (2007Volokh ( , 2010Volokh ( , 2017 introduced the energy limiter concept to limit the stored energy in aged elastomers when subjected to mechanical loading, and therefore, described the stress drop and the entire stress-strain response. Researchers also proposed an approach based on the intrinsic defect concept to predict the ultimate stresses and strains when thermo-oxidative aging is involved (Naït- Abdelaziz et al, 2012;Hassine et al, 2014;Sadeg et al, 2017;Abdelaziz et al, 2019;Rezig et al, 2020). Abdelaziz et al (2019) (and more recently Kadri et al (2022)) used the stress limiter approach (and energy limiter approach) to predict the aging effects on stresses and strains at fracture for rubbers based on changes in molar mass (and concentration of elastically active chains and swelling ratio).…”

Fracture analysis of V‐notched rubbers: An experimental and theoretical study

“…Although analysis of rubber under fatigue loading has attracted much attention during the last two decades, the rupture assessment of elastomers under quasi‐static loading is less documented . Moreover, due to the unique physics of rubber as stated before, presentation of a fracture criterion considering the rubber physics as the central part of criterion is of paramount importance.…”

“…Although analysis of rubber under fatigue loading has attracted much attention during the last two decades, [16][17][18][19][20][21][22][23] the rupture assessment of elastomers under quasi-static loading is less documented. 24 Moreover, due to the unique physics of rubber as stated before, presentation of a fracture criterion considering the rubber physics as the central part of criterion is of paramount importance. In this regard, the present authors recently developed a displacement-based criterion for rupture prediction of cracked rubbers which is called the effective stretch (ES) criterion.…”