Adviser: Florin Bobaru Damage and failure in composite materials under dynamic loading has been extensively studied in experiments for several decades. Composite materials exhibit various damage and failure patterns under different loading rates, such as splitting and branching. Classical models cannot directly be applied to problems with discontinuous fields. A new nonlocal continuum model, pe...

A subcapital femoral neck fracture complicating a healed trochanteric fracture is rare. Such cases are managed in a rather heterogeneous manner, i.e. there exists a mixture of cases treated by either fixed angle devices or dynamic compression screws. We describe 5 patients who developed subcapital femoral neck fractures after healed trochanteric fractures treated with dynamic compression screws...

The aim of this study was to comparatively evaluate the bending resistance at 45º, the static and dynamic cyclic fatigue life, and the fracture type of the WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) 25-08 and Reciproc (VDW, Munich, Germany) 25-08 instruments. A total of 60 nickel-titanium (NiTi) instruments (30 Reciproc and 30 WaveOne) from three different lots, each of which was 25 ...

The dynamic fracture behavior of layered architectures is experimentally studied. Specifically, crack penetration, trapping, and branching at an interface are examined. A newly introduced optical technique called Digital Gradient Sensing (DGS) that quantifies elasto-optic effects due to a non-uniform state of stress is extended to perform full-field measurements during the fracture event using ...

The study of rock fractures is essential in evaluating stability of underground structures, understanding earthquakes, and assessing storage and transport of oil and gas in rock formations. Geophysical monitoring techniques, particularly compressional and shear wave propagation, can probe the internal structure of rock and fractures remotely and nondestructively and can provide insight into fra...

PURPOSE In this study, a temporal abutment fixation screw, designed to fracture in a controlled way upon application of an occlusal force sufficient to produce critical micromotion was developed. The purpose of the screw was to protect the osseointegration of immediate loaded single implants. MATERIALS AND METHODS Seven different screw prototypes were examined by fixing titanium abutments to ...

the dynamic behavior of three high manganese steels with very different stacking faultenergy (sfe) values (4-30 mj/m2) were studied using high strain rate torsional tests. the hotrolledmicrostructure of the steel with the lowest sfe of 4 mj/m2 consisted of a duplex mixture ofaustenite and ε-martensite, but those of the other two steels were fully austenitic. the deformedmicrostructures were stu...

Brittle materials such as rock and ceramic usually exhibit apparent increases of strength and toughness when subjected to dynamic loading. The reasons for this phenomenon are not yet well understood, although a number of hypotheses have been proposed. Based on dynamic fracture mechanics, the present work offers an alternate insight into the dynamic behaviors of brittle materials. Firstly, a sin...