Size dependency of tension strength in natural fiber composites

Dill-Langer, Gerhard; Hidalgo, R. C.; Kun, Ferenc; Moreno, Yamir; Aicher, Simon; Herrmann, H. J.

doi:10.1016/s0378-4371(03)00141-9

Cited by 29 publications

(17 citation statements)

References 23 publications

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“…Neither of these two extremes are realistic, however they are important in establishing limiting behaviors of the model. Particularly, for local load sharing, the local stress concentration around damage is so high that the failure statistics is governed by extreme statistics [26][27][28][29] and the critical load for the system decreases with system size [30,31]. On the other hand, a global load sharing model gives a finite failure threshold, as the stress concentration is much lower here.…”

Section: Introductionmentioning

confidence: 99%

Modes of failure in disordered solids

2017

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The two principal ingredients determining the failure modes of disordered solids are the strength of heterogeneity and the length scale of the region affected in the solid following a local failure. While the latter facilitates damage nucleation, the former leads to diffused damage-the two extreme natures of the failure modes. In this study, using the random fiber bundle model as a prototype for disordered solids, we classify all failure modes that are the results of interplay between these two effects. We obtain scaling criteria for the different modes and propose a general phase diagram that provides a framework for understanding previous theoretical and experimental attempts of interpolation between these modes. As the fiber bundle model is a long-standing model for interpreting various features of stressed disordered solids, the general phase diagram can serve as a guiding principle in anticipating the responses of disordered solids in general.

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Section: Introductionmentioning

confidence: 99%

Modes of failure in disordered solids

2017

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“…[5][6][7][8][9][10] The relations can be described by Weibull statistics. [11][12][13][14] The mechanical properties of fibrereinforced composites are determined by: multiple factors: Besides the fibre load, the aspect ratio and the fibre-matrix adhesion are especially important. The aspect ratio of the fibres should be greater than 30 as a minimum, but should better exceed 100.…”

Section: Introductionmentioning

confidence: 99%

Cellulose‐Nanocomposites: Towards High Performance Composite Materials

Kohler

Nebel

2006

Macromolecular Symposia

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Strong cellulose fibres, e.g. flax and hemp, are increasingly used for composites. Despite substantial advantages, the tensile strength of these fibres is limited due to their complex structure and the unavoidable imperfections of the cell wall, inherent from growth or induced by processing. Essential improvements are possible by using highly crystalline cellulose fibrils (''whiskers'') which can be isolated from the cell wall, thus eliminating the influence of adhesion and defects. Instead of complete fibrillation, which demands special time consuming processing, a partly fibrillation has been achieved by adapted textile finishing procedures which have the potential for mass production. By combining chemical and mechanical/hydro-mechanical treatments it is possible to produce finest fibrils with diameters from below 1 mm down to the nanometer range. The problem of fibril agglomeration during drying has been avoided by forming homogenous fibrous sheets in a wet-laid non-woven process. These sheets can be impregnated with thermosetting resins. Alternatively thermoplastic polymers can be directly integrated to form hybrid materials ready for moulding. The resulting composites show greatly enhanced mechanical properties.

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“…approaching the critical load the system is characterized by scaling laws with exponents independent of specific material properties Kun et al, 2003a, b). The microscopic mechanism of creep of our model is relevant for natural fibre composites like wood (Dill-Langer et al, 2003), but can also be simply extended to more complex material behaviours (Nechad et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

“…The viscoelastic fibre bundle model with the equation of motion Equation (1) can provide an adequate description of natural fibre composites like wood subjected to a constant load (Dill-Langer et al, 2003). For the behaviour of the solutions ε(t) of Equation (1) two distinct regimes can be distinguished depending on the value of the external load σ o : when σ o falls below a critical value σ c , Equation (1) has a stationary solution ε s , which can be obtained by settingε = 0, i.e.…”

Section: Fibre Bundle Model Of Creep Rupturementioning

confidence: 99%

“…Interfacial failure also occurs in fibre reinforced composites, where debonding of the fibrematrix interface is an important damage mechanism. Since disordered properties of the glue play a crucial role in the failure of interfaces, most of the theoretical studies in this field rely on discrete models (Herrmann and Roux, 1990;Chakrabarti and Benguigui, 1997;Delaplace et al, 1999;Roux, 2000;Hidalgo et al, 2001;Dill-Langer et al, 2003;Raischel and Herrmann, 2005) which are able to capture heterogeneities and can account for the complicated interaction of nucleated cracks.…”

Section: Introductionmentioning

confidence: 99%

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Extension of fibre bundle models for creep rupture and interface failure

et al. 2006

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We present two extensions of the classical fibre bundle model to study the creep rupture of heterogeneous materials and the shear failure of glued interfaces of solid blocks. To model creep rupture, we assume that the fibres of a parallel bundle present time dependent behaviour under an external load and fail when the deformation exceeds their local breaking threshold. Assuming global load sharing among fibres, analytical and numerical calculations showed that there exists a critical load below which only partial failure occurs while above which the system fails globally after a finite time. Approaching the critical point from both sides the system exhibits scaling behaviour which implies that creep rupture is analogous to continuous phase transitions. To describe interfacial failure, we model the interface as an array of elastic beams which experience stretching and bending under shear load and break if the two deformation modes exceed randomly distributed breaking thresholds. The two breaking modes can be independent or combined in the form of a von Mises type breaking criterion. In the framework of global load sharing, we obtain analytically the macroscopic constitutive behaviour of the system and describe the microscopic process of the progressive failure of the interface.

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Size dependency of tension strength in natural fiber composites

Cited by 29 publications

References 23 publications

Modes of failure in disordered solids

Modes of failure in disordered solids

Cellulose‐Nanocomposites: Towards High Performance Composite Materials

Extension of fibre bundle models for creep rupture and interface failure

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