Composite restorations accumulate more biofilm than other dental materials. This increases the likelihood for the hard tissues supporting a restoration (i.e. dentin and enamel) to be exposed to acidic conditions beyond that resulting from dietary variations. In this investigation the fatigue strength and fatigue crack growth resistance of human coronal dentin were characterized within a lactic ...

Ultrasonic methods have been implemented for in situ sizing of fatigue cracks near fastener holes. These techniques, however, only provide an estimate at the time of the measurement and cannot predict the remaining life of the structure. In contrast, statistical crack propagation approaches model the expected fatigue life based on worst-case fatigue process assumptions. The authors have recentl...

A turbine blade root contains notches that locate into a “fir-tree” root fixing in the turbine disc. Fatigue initiation in these stress concentrating features is of some concern. When a turbine blade is cast, the primary orientation along the blade is controlled (usually in the <001> direction) to within certain limits, however the secondary orientation (i.e. the orientation of any notches) is ...

ÐBy incorporating the e€ects of interfacial adhesion in the mechanics of rounded contact between two bodies, a new approach is proposed for the quantitative analysis of a wide variety of contact fatigue situations involving cyclic normal, tangential or torsional loading. In this method, conditions of ``strong'' and ``weak'' adhesion are identi®ed by relating contact mechanics and fracture mecha...

S. Bulatović, Yugoslav River Shipping, Serbia, Lj. Milović, University of Belgrade, Faculty of Technology and Metallurgy, Serbia, A. Sedmak, University of Belgrade, Faculty of Mechanical Engineering, Serbia, I. Samardžić, University of Osijek, Mechanical Engineering Faculty, Slavonski Brod, Croatia Low cycle fatigue test was performed in ambient atmosphere at room temperature. Cycle loading of ...

The addition of liquid-filled urea-formaldehyde (UF) microcapsules to an epoxy matrix leads to significant reduction in fatigue crack growth rate and corresponding increase in fatigue life. Mode-I fatigue crack propagation is measured using a tapered doublecantilever beam (TDCB) specimen for a range of microcapsule concentrations and sizes: 0, 5, 10, and 20% by weight and 50, 180, and 460 lm di...

In this dissertation the work done in the projects KME-410/502 will be presented. The overall objective in these projects is to evaluate and develop tools for designing against fatigue in single-crystal nickel-base superalloys in gas turbines. Experiments have been done on single-crystal nickel-base superalloy specimens in order to investigate the mechanical and fatigue behaviour of the materia...

Recent high-cycle fatigue (HCF) related failures of gas-turbine jet engines have prompted a re-examination of the design methodologies for HCF-critical components, such as titanium alloy turbine blades. As foreign-object damage (FOD) from ingested debris is a key concern for HCF-related failures of such blades, the current study is focused on the role of simulated high velocity FOD in affecting...

Crack initiation mechanisms under two stress ratios (R = ? 1 and 0.5) up to very-high-cycle fatigue (VHCF) regime of a selective laser melted (SLMed) Ti-6Al-4V were investigated. Type I lack-of-fusion defects (almost equiaxed) induced crack except for the cases VHCF R 0.5 in which type II (large aspect ratio) caused facet mode initiation. A nanograin layer formed underneath region rough area at...