Numerical prediction of mechanical behavior of acrylonitrile-butadiene-styrene under three-point bending and impact loadings by Anand–Gurtin material model

Abstract

A satisfactory reproduction of three-point bending and impact test data of an industrially important amorphous polymer, acrylonitrile-butadiene-styrene (ABS), in the context of finite element analysis is of prime importance to industry. Constitutive material models developed for amorphous polymers are capable of describing their complex mechanical behavior under multiaxial loadings with a variety of success; therefore, the computational accuracy directly depends on the selection of constitutive model and a proper determination of its associated parameters. Thus, this study aimed at accurately predicting the multiaxial mechanical behavior of ABS by the Anand–Gurtin elastic–viscoplastic material model selected as the constitutive model and employed for the first time in the numerical implementations of the three-point bending and impact tests of ABS. To this end, the constitutive model parameters never identified for ABS before was first determined mainly depending on uniaxial compression test data at various strain rates ranging from 2 × 10−4 s−1 to 2 × 10−1 s−1 and then validated against tension test data for a broad range of strain rates varying from 1 × 10−3 s−1 to 45 s−1. All the experimental data taken into consideration in this study was taken from the previous studies of authors. The material model with the validated constitutive parameters of ABS was utilized in the numerical implementation of three-point bending tests for two different bending speeds (0.05–10 mm/s), in addition, impact tests for two various low impact velocities (4.43–6.23 m/s). Numerical results revealed that the constitutive model successfully reproduces the three-point bending test data of ABS for both bending speeds but acceptably overestimates the impact response of ABS under both low impact velocities in terms of peak impact load. Hence, it was concluded that this computationally inexpensive complex material model with the constitutive parameters determined for ABS can be used in the accurate prediction of its multiaxial material behavior.

Investigation of effects of added hemp fiber particles on tensile behavior of acrylonitrile-butadiene-styrene

“…Although the origin of strain softening is not well-known yet, 36,69 it has been claimed that damage-induced plastic localization or physical aging are the reasons for strain softening. 34,69 Micro-shear band deformation, which eventually initiates a macroscopic plastic zone called necking, has also been implicated as the cause of strain softening. [70][71][72] During the actual tension tests at all strain rates, necking was observed in ABS/Hemp-1 and ABS/Hemp-5, while almost not observed in ABS/Hemp-10.…”

“…In other words, relying on only tension test data is not sufficient to assess their actual material behaviors under multiaxial loads like bending and impact. 2,3,6,34,68 Thus, there is a high need in testing these manufactured biocomposites under bending and impact loadings in order to ascertain their actual mechanical behaviors.…”

“…Based on the results tabulated in Table 3, strain rate sensitivity parameters calculated by using equation ( 9) and As well-known for a long time, both the elastic and plastic material qualities of polymers are highly dependent on strain rate. 4,34,36,75 A significant number of rigorous studies has been devoted to understanding the strain rate effect on the material behavior of polymers. 1,68,76 Those studies have revealed that increasing strain rate leads to an increase in modulus of elasticity and yield strength of polymers.…”

“…In polymers, engineering stress–strain data does not provide any reliable results in terms of elastic modulus and yield strength. 3,5,32–34 Therefore, true stress–strain data was computed by taking into account the following formulae.Herein, normalσTrue and normalεTrue denote the true stress and true strain, respectively. In the same manner, normalσeng and normalεeng represent the engineering stress and engineering strain, respectively.…”

“…In polymers, engineering stress-strain data does not provide any reliable results in terms of elastic modulus and yield strength. 3,5,[32][33][34] Therefore, true stress-strain data was computed by taking into account the following formulae.…”