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Mechanical and Civil Engineering Seminar

Thursday, March 28, 2019
11:00am to 12:00pm
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Gates-Thomas 135
Breaking Badly: Chasing Fractures from Tectonic to Table-Top Scales

Mechanics of fracture and failure of solids continues to elicit challenges in terms of modeling and simulation, and investigation of the physical mechanisms in a range of engineering, biological and geological materials like metals, polymers, and rocks. Here, I will give an overview of two major efforts in my group focusing on addressing the multiscale nature of fracture in two seemingly different but societally relevant applications: (1)Physics-based modeling of earthquake propagation on frictional interfaces , and (2) modeling of fracture in soft materials.

In the first half of my talk, I will focus on a new computational algorithm for modeling earthquake ruptures with high resolution fault zone physics. I will present a hybrid method that combines Finite element method (FEM) and Spectral boundary integral (SBI) equation through the consistent exchange of displacement and traction boundary conditions, thereby benefiting from the flexibility of FEM in handling problems with nonlinearities or small-scale heterogeneities and from the superior performance and accuracy of SBI. I will present a verification of the hybrid method using a benchmark problem from the Southern California Earthquake Center’s dynamic rupture simulation validation exercises and show that the method enables exact near field truncation of the elastodynamic solution. I will further demonstrate the capability and computational efficiency of the hybrid scheme for resolving off-fault complexities using a unique model of a fault zone with explicit representation of small scale secondary faults and branches enabling new insights into earthquake rupture dynamics that may not be realizable in homogenized isotropic plasticity or damage models. Next, I will briefly discuss our recent efforts in extending this method to consistently simulate sequences of seismic and aseismic slip in a fault zone by combining adaptive explicit and implicit integration schemes enabling us to vary the time step over more than seven orders of magnitude and to potentially explore the interplay between geometric, rheological, and frictional complexities over short and long time scales.

For more information, please contact Carolina Oseguera by phone at 626-395-4271 or by email at susta@caltech.edu

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