Micromechanics on the Rate-dependent Fracture of Discontinuous Fiber-reinforced Plastics

Abstract

Numerical simulation by finite element analysis was used to investigate the relationship between the strength of glass fiber reinforced plastic (GFRP) and fiber length. Load speed dependability was also investigated, since thermoplastic resin used for GFRP exhibits much nonlinear stress-strain behavior and strong dependency on load speed. For this purpose, we conducted a periodic-cell simulation to address the effect of composite microstructure, matrix viscoplasticity, and microscopic damage (fiber break and matrix crack). When the fiber length was varied, the damage pattern was divided into two patterns: fiber-avoiding propagation and fiber-breaking modes of the matrix crack from fiber ends. When the matrix crack easily propagated in a fiber-avoiding way for shorter fiber lengths, the rate-dependent effect of the matrix was significant. Moreover, we considered the length at which the fracture mode changed based on this analysis, and compared it with the conventional critical length given by Kelly. Since the conventional critical length does not ensure improved composite strength, the consideration of the damage mode transition is essential for selecting the appropriate fiber length for strength improvement.

Numerical simulation of microscopic damage and strength of fiber-reinforced plastic composites

“…For matrix elements, the constitutive law described above is used. This formulation was coupled with periodic-cell simulation [12] to perform simulations using the periodic-cell model. Following the routine operation employed in homogenization [13,14], for thermosetting resin, Equation (16) is then transformed into the following equation.…”

“…Recently, we developed a new simulation scheme for a unit-cell model in order to analyze the microscopic damage and failure of fiber-reinforced composites [10][11][12][13]. In this study, we use this scheme to investigate changes in failure mode and tensile strength due to changes in matrix type and fiber length.…”

Recent studies on numerical modelling of damage progression in fibre-reinforced plastic composites

“…This model has been applied to CFRPs, glass-fibre-reinforced polymers, and metal matrix composites. We extended these models to the failure process of short fibre reinforced composites (Okabe, et al, 2010, Sasayama, et al, 2013.…”

Effects of fiber cracking on elastoplastic-damage behavior of fiber-reinforced metal matrix composites

“…Emanating from the eigenstrain concept (Eshelby, 1957) and the micromechanical framework (Ju and Chen, 1994a, b, c;Tseng, 1996, 1997;Zhang, 1998, 2001;Ju and Sun, 2001;Sun and Ju, 2001;Lin and Ju, 2009;Feng and Yu, 2010;Yanase, 2010, 2011), the effective elastoplasticdamage behavior of fiber/particle-reinforced composites due to interfacial complete/partial debonding Lee, 2000, 2001;Liu et al, , 2006Ju et al 2006Paulino et al, 2006;Ju, 2007, 2008;Ju and Yanase, 2009;Okabe et al, 2010), particlecracking , and thermal residual effect Ju and Yanase, 2008;Zhang and Wang, 2010) have been investigated extensively in the literature. In addition, a number of studies regarding the effects of particle-cracking in particle-reinforced MMCs have been conducted under the unit-cell micromechanical framework and the finite element analysis.…”