The role of crack-tip shielding in in ̄uencing mixed-mode (mode I‡ II) fatigue-crack growth thresholds for large, through-thickness cracks in a Ti±6Al±4V turbine blade alloy is examined under high-cycle fatigue loading conditions, i.e., at a loading frequency of 1000 Hz in ambient temperature air for load ratios (Kmin=Kmax) of R ˆ 0:1±0.8. Techniques are developed to quantify crack-tip shielding...

The fatigue strength, effects of a notch on the fatigue strength, and fatigue crack growth rate of Ti-15Zr-4Nb-4Ta alloy were compared with those of other implantable metals. Zr, Nb, and Ta are important alloying elements for Ti alloys for attaining superior long-term corrosion resistance and biocompatibility. The highly biocompatible Ti-15Zr-4Nb-4Ta alloy exhibited an excellent balance between...

This paper summarises fatigue tests on Y-joints to estimate the influence of a post weld treatment method called Ultrasonic Impact Treatment. With this method the fatigue resistance could be increased significantly. Furthermore, tubular joints of tripod structures for offshore wind energy converters are analysed with numerical simulations to judge these welded joints with the hot-spot-concept. ...

In the framework of crack number density analysis, a theoretical investigation is carried out on the relationship between the statistical characteristics of fatigue initiation life and the stochastic growth of short fatigue cracks. The numerical results indicate that, compared with the influence of grain boundary resistance, the effect of the degree of randomness of crystallographic crack growt...

The purpose of this study was to investigate the lateral force and contribution shoulder horizontal adductor elbow extensor muscles activity during wide- narrow-grip bench press (BP) in various conditions, such as resistance-trained/non-trained, concentric/eccentric, muscle fatigue/non-fatigue. We measured on bar electromyographic (EMG) pectoralis major (PM) triceps brachii (TB) 10 RM BP with w...

The elevated plasma level of thyroxin and/or triiodothyronine in hyperthyroidism not only induces a transition from the innervated slow-twitch muscle fibers to fast-twitch fibers, but also changes the contractile function in transition muscle fibers. So the muscle weakness of thyrotoxic myopathy would relate to alteration in fatigability of tetanic contraction in muscles, especially in slow-twi...

Degradation of the cementitious bond between steel rebar and concrete and that between old and new mortar under cyclic shear loading was observed nondestructively by measuring the contact electrical resistance of the joint. Degradation, which caused a decrease in bond strength but no visual damage, was indicated by an abrupt increase in the resistance at a small fraction of the fatigue life. Bo...

A metallurgical zirconium nitride (ZrN) layer was fabricated using glow metallurgy using nitriding with zirconiuming prior treatment of the Ti6Al4V alloy. The microstructure, composition and microhardness of the corresponding layer were studied. The influence of this treatment on fretting wear (FW) and fretting fatigue (FF) behavior of the Ti6Al4V alloy was studied. The composite layer consiste...

Bond wire lift-off is one of the major failure mechanisms in insulated gate bipolar transistor (IGBT) modules. Detecting fault bond wires important to avoid open-circuit IGBT ensure reliable operation power converters. In this paper, we propose a novel fatigue detection method for IGBT, which could be used normal working conditions. Firstly, investigated dependence on heatsink thermal resistanc...

INTRODUCTION The performance and mechanical properties of nickel-titanium (NiTi) instruments are influenced by factors such as cross-section, flute design, raw material, and manufacturing processes. Many improvements have been proposed by manufacturers during the past decade to provide clinicians with safer and more efficient instruments. METHODS The mechanical performance of NiTi alloys is s...