Department of Civil Engineering

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Subject: search.filters.subject.Crack branching

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    Numerical modelling of crack initiation, propagation and branching under dynamic loading
    (Elsevier, 2020-02) Islam, Md Rushdie Ibne
    In this paper crack initiation, propagation and branching phenomena are simulated using the Pseudo-Spring Smoothed Particle Hydrodynamics (SPH) in two and three-dimensional domains. The pseudo-spring analogy is used to model material damage. Here, the interaction of particles is limited to its initial immediate neighbours. The particles are connected via springs. These springs do not provide any extra stiffness in the system but only define the level of interaction between the connecting pairs. It is assumed that a crack has passed through a spring connecting a particle pair if the damage indicator of that spring becomes more than a predefined value. The crack branching of a pre-notched plate under dynamic loading and the effect of loading amplitude are studied. The computed crack speeds, crack paths and surfaces are compared with experimental and numerical results available in the literature and are found to be in good agreement. Next, the effect of notch location for a plate with a circular hole is studied. The ability of the framework to model arbitrary crack paths and surfaces are also demonstrated via three-dimensional simulations of chalk under torsion, Kalthoff-Winkler experiment, Taylor bullet impact and crack branching.
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    A comparison of numerical stability for ESPH and TLSPH for dynamic brittle fracture
    (Elsevier, 2023-10) Islam, Md Rushdie Ibne
    Dynamic brittle fracture is a numerically challenging problem that involves crack nucleation, formation, propagation, and material fragmentation. In this work, we use two forms of Smoothed Particle Hydrodynamics (SPH), namely Eulerian SPH (ESPH) and Total Lagrangian SPH (TLSPH) augmented with the pseudo-spring or virtual-link analogy for seamless modelling of crack formation, subsequent propagation, and material fragmentation. Being particle-based in nature, SPH is naturally capable of capturing finite deformation in materials, and the pseudo-spring or virtual-link analogies provide modelling of multiple discrete cracks without any additional condition, such as visibility criteria. We simulate the crack branching and propagation in a brittle polymeric material subjected to biaxial tensile loading with a pre-existing central notch. The numerical results using ESPH and TLSPH agree with the previously published experimental and numerical results. We have also simulated the dynamic fragmentation of a cylinder and compared the results. This work shows the capability of both ESPH and TLSPH frameworks to model dynamic brittle fracture especially crack branching and curving. It is also observed that the ESPH and TLSPH frameworks present similar results for minor material deformation problems. However, the ESPH framework shows better stability and capability for finite material deformation problems.