Microstructure‐based fatigue modeling of an acrylonitrile butadiene styrene (ABS) copolymer

Abstract

International audienceIn this article, we experimentally investigate the structure-property relationships of an acrylonitrile butadiene styrene (ABS) copolymer for fatigue and use a microstructure-based multistage fatigue (MSF) model to predict material failure. The MSF model comprises three stages of fatigue damage (crack incubation, small crack growth, and long crack growth) that was originally used for metal alloys. This study shows for the first time that the MSF theory is general enough to apply to polymer systems like ABS. The experimental study included monotonic testing (compression and tension) and fully reversed uniaxial cyclic tests at two frequencies (1 Hz and 10 Hz) with a range of strain amplitudes of 0.006 to 0.04. Cyclical softening was observed in the ABS copolymer. Fractography studies of failed specimens revealed that particles were responsible for crack incubation. Although polymeric materials can be argued to be more complex in terms of failure modes and thermo-mechano-chemical sensitivity when compared with most metal alloys, results showed that the MSF model could be extended successfully to capture microstructural effects to polymeric materials

Interfacial mechanical behavior of 3D printed ABS

“…The toughness of the amorphous, glassy styrene acrylonitrile monophase is increased by the addition of the non‐continuous rubbery butadiene phase. Several parameters control this morphology‐toughness behavior, including particle size, particle nearest neighbor distance, matrix particle adhesion strengths, and the mechanical properties of particles themselves . While the ratios of the three constituents may be varied for a given application, the resulting polymer is typically formulated to achieve a balance of toughness, strength, and temperature resistance.…”

Effects of microstructural inclusions on fatigue life of polyether ether ketone (PEEK)

“…In addition, the MSF model was correlated to a multi-phase polymer system (acrylonitrilebutadiene-styrene) and found to be successfully capturing the microstructural features and effects on strain-life fatigue behavior of the material [8].…”

“…The parameter ∆ߪ ො in Equation (11) represents the multiaxial fatigue term. Additionally, due the lack of well-defined microstructure of polymer, the grain size effect and grain orientation effect for polymers are assumed to be unity [8]. The LC growth of the MSF model is characterized using the classical linear elastic fracture mechanics approaches and is not included in this study.…”

“…Other MSF parameters used in this stage were previously obtained by finite element simulation [20]. Proportionality constant, ߯, is defined as ఙ ఙ ೠ [22] and crack tip displacement threshold, ‫ܦܶܥ∆‬ ௧ , is defined as the shear displacement of the sheared region of a polymer [8]. Besides the microstructural features of PEEK polymer, the cyclic strength coefficient, ‫,′ܭ‬ and hardening exponent, ݊′, obtained from the fatigue experiments are also required in the MSF model.…”

“…Due to the differences in microstructures between polymeric and metallic materials, their mechanisms underlying fatigue failure are also expected to be different. However, their overall fatigue process is similar, with crack initiating from the regions with higher stress concentration resulted from the foreign inclusions, defects, or impurities within the materials [2,8].…”