Current understanding of ultra-high cycle fatigue

Ultra-Low Cycle Fatigue Fracture Life of a Type of Buckling Restrained Brace

Buckling restrained braced frames (BRBFs) for seismic load resistance have been widely used in recent years. One of the key requirements for a buckling restrained brace is to sustain large plastic deformations under severe ground motions. The core of a buckling restrained brace is prone to fatigue fracture under cyclic loading. The earthquake induced fracture type of the core plate in a bucklin...

Ultra Low Cycle Fatigue of Axisymmetric Freestanding Nanoscale Gold Films

We present ultra low-cycle fatigue experiments of axisymmetric nano-crystalline gold films of nano-thickness deformed by a spherical indenter using a recently developed freestanding membrane test. Freestanding membranes of gold were centrally deflected using a spherical indenter attached to a MEMS load cell. Fabrication of the films for these experiments yielded films 100 nm thick and 500 μm in...

Rolling Contact Fatigue in Ultra High Vacuum

A Novel ±0.5V Ultra High Current Drive and Output Voltage Headroom Current Output Stage with Very High Output Impedance

A novel ultra-high compliance, low power, very accurate and high output impedance current output stage (COS) with extremely high output current drive capability is proposed in this paper. The principle of operation of this unique structure is discussed, its most important formulas are derived and its outstanding performance is verified by HSPICE simulation in TSMC 0.18µm CMOS, BSIM3, and Level4...

Propagation Lifetime from the Surface and Internal Defects in the Ultra High Cycle Fatigue Regime

Ultra High Cycle fatigue leads to a failure initiated in the bulk material of a material. Some results on the nodular cast iron are presented: initiation occurs from the defects, located at the surface or in the bulk. It has been shown that environment plays a major role that could explain the difference between fatigue lives, for the surface and internal initiation. The influence of the defect...