A Thermomechanical Modeling and Simulation of Viscoplastic Large Deformation Behavior for Polymeric Materials. 2nd Report, Vertex Model Based on Flow Rule and Its Finite Element Analysis.

Discontinuous fiber-reinforced composites have better productivity and formability than continuous fiber-reinforced composites. However, their strength is remarkably low. Thus, there is an urgent need to improve the strength of discontinuous fiber-reinforced plastic composites. In this study, we utilized a unit-cell model that considers microscopic damage including matrix cracking and fiber breaking, and incorporates constitutive laws of thermosetting resin or thermoplastic resin for the matrix. The tensile damage and strength of the composite were investigated for various fiber lengths and/or matrix properties. We compared the simulated strengths with experiments for carbon fiber-reinforced polypropylene. The effect of deformation rate on mechanical behavior was also investigated.

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“…The equivalent strain rate _ e p is defined by the following hardening rule for the PP matrix (Murakami et al [9]):…”

Section: Advanced Composite Materials 149mentioning

confidence: 99%

“…The first term represents craze growth due to plastic volumetric expansion strain e p m [9], while the second term represents craze initiation and annihilation. Here, A and B are nondimensional constants.…”

Section: Advanced Composite Materials 149mentioning

confidence: 99%

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

Okabe

Motani²,

Nishikawa

et al. 2012

Advanced Composite Materials

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“…The equivalent strain rate _ " p is defined by the following hardening rule for the PP matrix, reported by Murakami et al (2002).…”

Section: Periodic Cell Simulationmentioning

confidence: 99%

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

Okabe

Nishikawa

Takeda

2009

International Journal of Damage Mechanics

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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.

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“…program developed for predicting the craze nucleation and growth of PP blends in the previous studies [31][32][33][34] while there has been considerable amount of work concerning the modeling of elastoviscoplasticdamage behavior of polymers. [35][36][37][38] RADIOSS offers the way to introduce an advanced material model into a numerical scheme through user-defined subroutine: User Material Laws.…”

Section: Calibration Procedures Of Plasticity and Fracture Properties mentioning

confidence: 99%

“…The more detail description can be found in Ref. 38 The proposed elastoviscoplastic constitutive equation with craze effect 31,32 is given by;…”

Section: Calibration Procedures Of Plasticity and Fracture Properties mentioning

confidence: 99%

Characterization of material ductility of PP/EPR/talc blend under wide range of stress triaxiality at intermediate and high strain rates

Mae

2008

J of Applied Polymer Sci

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A ductile fracture locus formulated in the space of the effective plastic strain to fracture and the stress triaxiality for the polypropylene (PP) blended with ethylene-propylene rubber (EPR) and talc fillers is obtained at the intermediate and high strain rates by using a combined experimental-numerical approach. Biaxial loading tests on the flat butterfly specimens are carried out to characterize fracture behaviors under pure shear, combined shear and tension, pure tensile loading conditions at various loading velocities. Corresponding finite element analysis is performed to determine the evolution of stress, strain, and strain rate states. It is found that the material ductility strongly depends on the stress triaxiality for the present PP/EPR/talc blend. Meanwhile, the fracture surfaces are observed by scanning electron microscopy, revealing that there exist two competing failure mechanisms: the multiple crazing at high positive stress triaxialities and void-sheeting like fracture mode at the low stress triaxiality. The transition of the failure modes occurs in the intermediate range of stress triaxialities. The obtained fracture locus covers a wide range of the stress triaxiality. It would be applicable to the fracture analysis of real automotive components such as interior or exterior polymeric components under various impact loading conditions.

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A Thermomechanical Modeling and Simulation of Viscoplastic Large Deformation Behavior for Polymeric Materials. 2nd Report, Vertex Model Based on Flow Rule and Its Finite Element Analysis.

Cited by 15 publications

References 0 publications

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

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

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

Characterization of material ductility of PP/EPR/talc blend under wide range of stress triaxiality at intermediate and high strain rates

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