Lattice Trapping of Fracture Cracks

Thomson, Robb; Hsieh, Chi Tai; Rana, Verinder S.

doi:10.1063/1.1660699

Cited by 374 publications

(173 citation statements)

References 3 publications

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“…The variation in energy release rate indicated by Eq. 3 is analogous to the phenomenon of lattice trapping of a crack (38), which has the consequence of enhanced work of fracture and irreversibility (39). It is reasonable to assume that the periodic energy storage and release rate will scale with the remote loading, or…”

Section: Resultsmentioning

confidence: 99%

Biologically inspired crack trapping for enhanced adhesion

Glassmaker

Jagota

Hui

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

245

270

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We present a synthetic adaptation of the fibrillar adhesion surfaces found in nature. The structure consists of protruding fibrils topped by a thin plate and shows an experimentally measured enhancement in adhesion energy of up to a factor of 9 over a flat control. Additionally, this structure solves the robustness problems of previous mimic structures and has preferred contact properties (i.e., a large surface area and a highly compliant structure). We show that this geometry enhances adhesion because of its ability to trap interfacial cracks in highly compliant contact regimes between successive fibril detachments. This results in the requirement that the externally supplied energy release rate for interfacial separation be greater than the intrinsic work of adhesion, in a manner analogous to lattice trapping of cracks in crystalline solids.interface ͉ fracture ͉ fibrillar ͉ lattice trapping ͉ biomechanics T he ability to adhere two surfaces strongly together and then reversibly separate them, repeatedly, is a desirable capability that is rarely achievable using conventional fabrication techniques and materials. Nevertheless, fibrillar surfaces with these properties have evolved in nature on the adhesive surfaces of the feet of many lizards and insects. With such natural surfaces as inspiration, we have developed a fibrillar structure that produces a robust, reusable material with strongly enhanced adhesion compared with a flat control of the same material, with the enhancement resulting only from the modification of surface geometry.The essential feature that our surfaces borrow from biology is the seta, a hair-like bristle having a diameter of 0.5-10 m and terminating in one or more flattened, expanded tips (''spatulas'') at its contacting end. A number of biological studies (1-16) have found that arrays of setae are a common feature on the adhesion surfaces of many lizards and insects. In the biological literature, the shape, dimensions, and composition of setae from various species are described (1-5, 9-16). Also, the mechanical properties and adhesion force of a single gecko seta (7) and even a single spatula (17,18) were the subjects of recent investigations. An important conclusion to emerge from these two studies is that setal arrays use noncovalent surface forces to achieve adhesion, and evidence suggests that geckos rely primarily on van der Waals and capillary forces (8, 18). As a result, the surface architecture is the primary design variable that has been adjusted in biological systems by evolution.Because of the extraordinary adhesion ability of animals that possess setal arrays, several researchers have recently made an effort to mimic the biological setal geometry by using synthetic materials (19)(20)(21)(22)(23)(24)(25)(26). It has been established theoretically that a fibrillar interface can increase both strength and interfacial toughness, compared with a flat control (21, 27-30). However, simple arrays of micropillars (19-21) have not exhibited stronger adhesion than flat control surfaces o...

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Section: Resultsmentioning

confidence: 99%

Biologically inspired crack trapping for enhanced adhesion

Glassmaker

Jagota

Hui

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

245

270

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“…This "lattice trapping" of cracks is well-established theoretically [33,34] and in atomistic simulations [35,36], and large lattice trapping is unexpected for most metallic systems. In order to identify the origin of the lattice trapping, we first computed the cohesive energy E 0 of crystalline Mg as a function of the lattice parameter a with c/a fixed.…”

Section: Meam Potentialsmentioning

confidence: 97%

Magnesium interatomic potential for simulating plasticity and fracture phenomena

Francis

Curtin

2014

Modelling Simul. Mater. Sci. Eng.

138

104

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Abstract.Magnesium has multiple dislocation and twinning systems with starkly different properties, which make its plastic deformation strongly anisotropic and highly complex. Existing empirical interatomic potentials fail to capture the full scope of these properties, making current molecular statics and dynamics simulation results of limited quantitative and predictive use. Here, based on the work by Kim et al, a new modified embedded-atom method potential for magnesium is introduced and rigorously validated against existing ab initio, continuum theory and experimental results. The new potential satisfactorily reproduces all the necessary mechanical properties for plastic deformation, including the various generalized stacking fault energy surfaces, dislocations core structures, Peierls stresses, surface energies, and basal plane cohesive strength. The capability of this potential to accurately describe all the important slip systems and fracture behavior makes it valuable for future realistic atomistic studies of general magnesium deformation and failure problems.

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“…Higher energy release rates lead to crack propagation in the initial (2110) plane. It is known that the discrete character of interatomic bonds which reveals itself in the so called lattice trapping effect 40 can retard crack propagation to energy release rates beyond the critical energy release rate determined by the Griffith criterion. As can be seen from Fig.…”

Section: Crack Propagation a Simulation Conditionsmentioning

confidence: 99%

Simulation of crack propagation in alumina with ab initio based polarizable force field

Hocker

Beck

Schmauder

et al. 2012

The Journal of Chemical Physics

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We present an effective atomic interaction potential for crystalline α-Al 2 O 3 generated by the program potfit. The Wolf direct, pairwise summation method with spherical truncation is used for electrostatic interactions. The polarizability of oxygen atoms is included by use of the Tangney-Scandolo interatomic force field approach. The potential is optimized to reproduce the forces, energies and stresses in relaxed and strained configurations as well as {0001}, {1010} and {1120} surfaces of Al 2 O 3 . Details of the force field generation are given, and its validation is demonstrated. We apply the developed potential to investigate crack propagation in α-Al 2 O 3 single crystals.

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Lattice Trapping of Fracture Cracks

Cited by 374 publications

References 3 publications

Biologically inspired crack trapping for enhanced adhesion

Biologically inspired crack trapping for enhanced adhesion

Magnesium interatomic potential for simulating plasticity and fracture phenomena

Simulation of crack propagation in alumina with ab initio based polarizable force field

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