Triangulation photo tesserae

Our projects

Hydraulic fracturing

contour plot of pressure
opening of our method vs time-discontinuous
Hydraulic crack growth over time

Hydraulic fracture trajectories obtained for hydro-fracture propagation in cemented naturally fractured block. Top left figure shows contours of water pressure; top right figure compares opening velocity for our method versus time-discontinuous method; bottom figure shows crack propagation in naturally fractured media.

Fracture-based fatigue

traction-displacement diagram for fatigue
diagram of fatigure sample
simulation of fatigure model
Number of cycles to failure
Experiment Simulation
R=0.1 570,830 579,000
R=0.5 705,440 737,000

A fatigue model based on cohesive-zone modeling and damage variables is illustrated in the top left. When tested computationally on a notched specimen shown in the lower left, the results closely match a laboratory experiment as shown on the right. We also developed a simple but effective extrapolation scheme that is able to reproduce laboratory experiments in the high-cycle regime, as shown in the above table.

Experiment with overlead cycle

The above graph shows a computational experiment that reproduces a known fatigue effect in which the fatigue crack growth is retarded following a single peak overload. Our model captured the effect that larger overload increases the degree of retardation.

Micromechanics of bone fracture

crack formation in single osteon

Convergent crack propagation solution in microscale osteonal structure of femur bone.

Viscoelastic frequency-dependent materials

J' results for viscoelastic model
tandelta results for viscoelastic model

Storage compliance (J') and loss tangent (tan δ) fitted to polyethylene data. Three, nine, and twenty seven rheological units approximation (the latter is not discernible as it matches the data exactly) without increase of model parameters. Fit is performed for a chosen frequency range and is not valid outside of it.