Mixed mode І/ІІ fracture prediction of blunt V-notched nanocomposite specimens with nonlinear behavior by means of the Equivalent Material Concept

Torabi, A.R.; Rahimi, A.S.; Ayatollahi, M.R.

doi:10.1016/j.compositesb.2018.09.025

Cited by 15 publications

(3 citation statements)

References 57 publications

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“…Therefore, the created prenotches are suitable for the determination of fracture toughness through Equation ( 1). As for the effect of the shape of the notch on the fracture toughness measurement, a series of studies [36][37][38][39][40] has been conducted. It has been found that the thickness of SCB samples has very limited effects on the stress intensity factor Y I 41 and mode-I fracture toughness K Ic.…”

Section: Determination Of Fracture Properties Of Fiber-reinforced Cpb...mentioning

confidence: 99%

Experimental investigation of fiber content and length on curing time‐dependent mode‐I fracture behavior and properties of cemented paste backfill and implication to engineering design

Fang

Cui

2022

Fatigue Fract Eng Mat Struct

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The inclusion of fiber in cemented paste backfill (CPB) can significantly alter the mechanical response of the CPB body. The intrinsic defects in CPB and the potential dynamic loading condition make it necessary to investigate the fracture properties of fiber-reinforced CPB (FR-CPB). The mode-I fracture behavior and properties are crucial to the successful engineering application of FR-CPB technology used in underground mines. The contribution of fiber length and content to the evolutive mode-I fracture behavior and properties of FR-CPB was examined in this study. The results show that the addition of fiber reduces the prepeak stiffness but improves the mode I fracture toughness (K Ic ), and the improvement in K Ic increases with fiber length. In contrast, the initial increase in fiber content (from 0% to 0.5%) benefits the K Ic acquisition, while a further increase in fiber content from 0.5% to 0.75% poses a negative influence on the K Ic development. Moreover, with the adoption of the cement hydration model, four predictive functions are proposed to describe the contribution of fiber length and content to the development of fracture properties. In addition, K Ic is identified as a more reliable fracture property for assessing the immediate ground support role played by the FR-CPB structure. The findings are helpful when it comes to the determination of the fiber length and content in FR-CPB design. K E Y W O R D Scemented paste backfill, fiber reinforcement, fracture toughness, tailings, underground mine List of abbreviations/symbols: CB, chevron bend; CCNBD, cracked chevron-notched Brazilian disc; FRCC, fiber-reinforced cementitious composites; FR-CPB, fiber-reinforced cemented paste backfill; K IC , mode I fracture toughness; LPD, load-point displacement; NT, natural tailings; PSD, particle size distribution; SCB, semicircular bending test; SR, short rod; ST, silicate tailings; TSF, tailings storage facilities; UCS, uniaxial compressive strength; w /c, water to cement ratio; T, thickness of sample; F l , fiber length; F c , fiber content; F lr , reference fiber length; a, notch length; D, diameter of sample; FM-ITZ, fiber-matrix interfacial transition zone; P, normal force; S, half of the distance between the two supporting rollers; R, radius of sample; k s , stiffness; E i , fracture initiation energy; E m , critical fracture energy; P m , peak force; Y I , stress intensity factor; u, displacement; i, stage number; E p , postpeak fracture energy; ξ f , final degree of cement hydration; ξ, degree of cement hydration; τ, curing time constant; β, shape constant; t e , curing time; T r , reference curing temperature; T c , actual curing temperature; E a , energy activating cement hydration; R', natural gas constant; a i , b i , c i , d i , fitting constants.

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Section: Determination Of Fracture Properties Of Fiber-reinforced Cpb...mentioning

confidence: 99%

Experimental investigation of fiber content and length on curing time‐dependent mode‐I fracture behavior and properties of cemented paste backfill and implication to engineering design

Fang

Cui

2022

Fatigue Fract Eng Mat Struct

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“…Also, Torabi et al. [49,50] have studied the fracture behavior of polymer-based nano-composite specimens weakened by blunt V-notches under mode I and mixed mode I/II loading conditions by means of the Equivalent Material Concept (EMC). They have shown that EMC combined with stress-based brittle fracture criteria can predict the load-carrying capacity (LCC) of ductile V-notched nano-composite specimens well.…”

Section: Introductionmentioning

confidence: 99%

“…The experimentally recorded LPF loads have been theoretically predicted by coupling the Virtual Isotropic Material Concept (VIMC) with two brittle fracture criteria, namely the maximum tangential stress (MTS) and the mean stress (MS) criteria, which are two of the four criteria known as the Theory of Critical Distances (TCD) [48]. Also, Torabi et al [49,50] have studied the fracture behavior of polymer-based nano-composite specimens weakened by blunt V-notches under mode I and mixed mode I/II loading conditions by means of the Equivalent Material Concept (EMC). They have shown that EMC combined with stressbased brittle fracture criteria can predict the load-carrying capacity (LCC) of ductile V-notched nano-composite specimens well.…”

Section: Introductionmentioning

confidence: 99%

Experimental verification of the virtual isotropic material concept for the last-ply-failure of U-notched quasi-isotropic E-glass/epoxy composite laminates under tension-shear loading

Torabi

Pirhadi

2020

Journal of Industrial Textiles

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Fracture investigation of U-notched E-glass/epoxy laminated composite specimens with various notch root radii is performed under mixed mode I/II loading conditions both experimentally and theoretically. Rectangular E-glass/epoxy composite laminates with two numbers of ply (8-ply and 16-ply) and the quasi-isotropic [0/90/+45/–45]s lay-up configuration are fabricated for conducting the fracture tests. To measure the damage initiation angles (DIAs) and the last-ply-failure (LPF) loads of the fabricated composite samples containing horizontal and inclined U-notches, as the main aim of this study, the specimens are loaded under tension by the universal testing machine. The experimental LPF loads are theoretically predicted with the aid of a novel concept, called the Virtual Isotropic Material Concept (VIMC). The proposed VIMC is linked to the two well-known stress-based fracture criteria, namely the maximum tangential stress (MTS) and the mean stress (MS) criteria, in the context of the linear elastic notch fracture mechanics (LENFM). It is proved that the two combined criteria, namely the VIMC-MTS and VIMC-MS criteria, can predict well the LPF loads of the U-notched laminated composite specimens tested under mixed mode I/II loading conditions. One of the important merits of these new criteria is that the predictions of the LPF loads of the U-notched composite specimens are performed without complicated and time-wasting ply-by-ply damage analyses.

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Nonlinear fracture assessment and nanomechanical deformation of elastomeric composites: Development of finite element model and experimental validation

et al. 2021

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In this article, Mode‐I fracture and nanomechanical deformation of elastomeric composites are studied using nonlinear fracture mechanics implicating computer modeling techniques like finite element analysis, and the models developed are verified experimentally. The effect of low notch‐to‐width ratios (NWR) on failure properties like J‐integral, geometry factor, crack tip opening displacement (CTOD), crack advancement, and R‐curves is investigated. The geometry factor is found to be decreasing by 96% when NWR is increased from 0.06 to 0.34. An empirical relationship between CTOD and crack advancement for hybrid elastomeric composites depending on NWR is developed and has been verified analytically. Optimization of silica in 10 phr carbon black filled styrene butadiene rubber is performed, and several characterization techniques are used to justify the outcome. The applicability of mechanical properties like stress contours and factor of safety in fracture characterization of composites is explained briefly. A mesh sensitivity based finite element model has been developed for calibrating the nanoindentation test of elastomeric composites and verified experimentally.

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Mixed mode І/ІІ fracture prediction of blunt V-notched nanocomposite specimens with nonlinear behavior by means of the Equivalent Material Concept

Cited by 15 publications

References 57 publications

Experimental investigation of fiber content and length on curing time‐dependent mode‐I fracture behavior and properties of cemented paste backfill and implication to engineering design

Experimental investigation of fiber content and length on curing time‐dependent mode‐I fracture behavior and properties of cemented paste backfill and implication to engineering design

Experimental verification of the virtual isotropic material concept for the last-ply-failure of U-notched quasi-isotropic E-glass/epoxy composite laminates under tension-shear loading

Nonlinear fracture assessment and nanomechanical deformation of elastomeric composites: Development of finite element model and experimental validation

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