Nadia Lapusta
Assistant Professor of Mechanical Engineering and Geophysics

BA/MA, Kiev State University, Ukraine; S.M., Harvard University, 1996, PhD, 2001

1200 East California Boulevard
Pasadena, CA 91125
MC 104-44

(626) 395-2277

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Research

Professor Lapusta's research interests are in continuum mechanics, computational modeling, fracture and frictional processes, and mechanics and physics of earthquakes. Her work is directed towards understanding fracture and frictional phenomena on all scales, from frictional failure in earthquakes and dynamic cracks in solid structural components to tribological processes on micron-sized asperities and complex atomic and molecular interactions at crack tips.

Recent studies addressed properties of macroscopic descriptions of friction, nucleation and dynamics of shear cracks on planar interfaces, and sequences of frictional ruptures with application to earthquakes. Under loading, interfaces either creep or exhibit stick-slip behavior, depending on their frictional properties. In the stick-slip regime, slip events occur in the form of frictional instabilities: slip starts on a part of the interface, then accelerates and ultimately results in a dynamic rupture rapidly propagating along the interface. It is important to understand how these failure events nucleate, propagate, and arrest. During the dynamic phase, shear heating effects, such as flash heating of asperity contacts and partial melting, become important. Partial melting introduces solid-fluid interactions. Dynamic failure also may result in off-interface damage and branching. These and other phenomena strongly influence the rupture process.

Significant efforts are devoted to developing efficient computational techniques applicable to such nonlinear, dynamic, and multi-scale problems.

Selected Publications

Transition of mode II cracks from sub-Rayleigh to intersonic speeds in the presence of favorable heterogeneity (with Y. Liu), J. Mech. Phys. Solids, 56, pp. 25-50, 2008.

Pulse-like and crack-like ruptures in experiments mimicking crustal earthquakes (with X. Lu and A. J. Rosakis), Proc. Natl. Acad. Sci. USA, 104, pp. 18931-18936, 2007.

Comparison of finite difference and boundary integral solutions to spontaneous rupture (with S. M. Day, L. A. Dalguer, and Y. Liu), J. Geophys. Res. 108, doi: 10.1029/2001JB000793, 2005.