Macro-mechanical damage modeling of fibrous composite materials accounting for non-linear material behavior

A unified damage model for fibrous composite laminae subject to in-plane stress-state and having multi material-nonlinearity

“…In a very recent work of Abu-Farsakh and Asfa (2018), a unique trend was found between material stiffness-degradation |Xi=EsiEoiof a unidirectional fibrous composite lamina and the corresponding modified-damage (MD) factor normal |1-φ*2. The new trend, as shown in Figure 2, can be considered as a unified relationship for such composite materials, since it is independent of fiber-orientation angle and case of loading.…”

“…Hence, many damage models were developed to simulate growth of damage in composite materials. Two main important approaches were followed in the literature to investigate the damage behavior of a composite lamina, experimental damage-inspection (Chowdhury et al., 2018; Hiremath et al., 2018; Huang et al., 2019; Zhao et al., 2018) using electronic-microscopy and damage-modeling (Abu-Farsakh and Asfa, 2018; Abu-Farsakh et al., 1999; Christian et al., 2018; Kattan and Voyiadjis, 1993; Schapery, 1990; Okabe et al., 2018; Pineda and Waas, 2013; Zhao et al., 2018) using macro- and micro-mechanical approaches.…”

“…Abu-Farsakh and Asfa (2018) proposed an efficient macro-model to trace damage evolution in a unidirectional composite-lamina in the case of general in-plane loading. They classified damage as longitudinal damage “Φ 1 ,” transverse damage “Φ 2 ,” and shear damage “Φ 12 .” It was found that the percentage-reduction of secant moduli of a composite-lamina is mainly affected by the amount of evolved damage irrespective of fiber-orientation.…”

“…Abu-Farsakh and Asfa (2018) assumed that a composite lamina failed when it reached a specific damage value, hence, the residual strength of a composite lamina can be estimated based on the amount of current damage as a percentage of failure damage. The composite materials, boron/epoxy, graphite/epoxy, and carbon/epoxy, with different fiber orientations were used to investigate directional damage evolution.…”

“…Because, relating damage to the total potential energy was improper to obtain such invariant relation. Thus, the only energy term which is proved to behave in an invariant manner in various composite laminas with respect to a damage-variable is shown to be the Plastic Strain Energy Density (PSED) of an equivalent linear elastic system (Abu-Farsakh, 1989; Abu-Farsakh and Al-Jarrah, 2018; Abu-Farsakh and Asfa, 2018).…”