نتایج جستجو برای: cyclic fatigue

تعداد نتایج: 166131  

Journal: :journal of rehabilitation sciences and research 0
saeed talebian department of physiotherapy, school of rehabilitation, tehran university of medical sciences, tehran, iran maryam saba department of physical therapy, school of rehabilitation, tehran university of medical sciences,tehran, iran hossein bagheri gholamreza olyaei shiva mousavi

background: surface electromyography (semg) of muscles is a non-invasive tool that can be helpful in the assessment of muscle function and some motor control evaluations. a loss of force, known as muscle fatigue is accompanied by changes in muscle electrical activity. one of the most commonly used surface emg parameters which reflects paraspinal muscle fatigue during different tasks and positio...

Journal: :journal of mechanical research and application 2012
e. kalateh mollaei h. jahed

with the expanding demand on application of magnesium alloys in automotive and aerospace industries, robust methods in fatigue characterization of commercially available magnesium alloys with high specific strength is anticipated. in this paper, rotating bending load controlled tests has been studied on specimens machined from an extrusion piece of az31b. due to asymmetric and anisotropic behav...

ژورنال: مهندسی دریا 2007
راشد, غلامرضا, قاجار, رحمت الله, هاشمی, سید جلال الدین,

During the offshore drilling operations by drillships or semisubmersible vessels the drillstring in its first drilljoint to the Kelly suffers bending due to float vessel roll or pitch. The cyclic bending stress at any point along the drillstring, is a function of the roll or pitch angle, Kelly position in bushing, and hookload. The cumulative fatigue damage of the drillpipe due to cyclic stress...

Journal: :Journal of the Formosan Medical Association = Taiwan yi zhi 2017
Chih-Wen Chi Chun-Chieh Li Chun-Pin Lin Chow-Shing Shin

BACKGROUND/PURPOSE Dental rotary instruments can be applied in multiple conditions of canals, but unpredictable fatigue fracture may happen. This study evaluated the fatigue lives of two batches of nickel-titanium (NiTi) dental rotary files operating in clinically simulated root canals. METHODS Single-step cyclic fatigue tests were carried out to assess the performance of two batches of NiTi ...

Journal: :iranian endodontic journal 0
shahram azimi parisa delvari hamid cyrus hajarian mohammad ali saghiri kasra karamifar mehrdad lotfi

introduction: this study investigated the fatigue and fracture modes of race and protaper rotary instruments. materials & methods: fatigue resistance was evaluated by rotating the files 30 ° or 60 ° and with 2 or 5mm radius of curvature. race taper 06 size 25 and protaper f1 files (n=40) were used. the number of rotations to failure was analyzed by two-way anova and independent sample     t-tes...

Journal: :Biomaterials 2005
R K Nalla J J Kruzic J H Kinney R O Ritchie

Although fatigue damage in bone induced by cyclic loading has been recognized as a problem of clinical significance, few fracture mechanics based studies have investigated how incipient cracks grow by fatigue in this material. In the present study, in vitro cyclic fatigue experiments were performed in order to quantify fatigue-crack growth behavior in human cortical bone. Crack-growth rates spa...

Journal: :Materials science & engineering. A, Structural materials : properties, microstructure and processing 2008
John J Lewandowski Ravikumar Varadarajan Brian Smith Chris Tuma Mostafa Shazly Luciano O Vatamanu

The mechanical behavior of 316LVM 1x7 cables were evaluated in uniaxial tension, and in cyclic strain-controlled fatigue with the use of a Flex tester operated to provide fully reversed bending fatigue. The magnitude of cyclic strains imparted to each cable tested was controlled via the use of different diameter mandrels. Smaller diameter mandrels produced higher values of cyclic strain and low...

E. Kalateh Mollaei H. Jahed

With the expanding demand on application of magnesium alloys in automotive and aerospace industries, robust methods in fatigue characterization of commercially available magnesium alloys with high specific strength is anticipated. In this paper, rotating bending load controlled tests has been studied on specimens machined from an extrusion piece of AZ31B. Due to asymmetric and anisotropic behav...

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...

Journal: :Biomaterials 2005
J J Kruzic R K Nalla J H Kinney R O Ritchie

Although the propagation of fatigue cracks has been recognized as a problem of clinical significance in dentin, there have been few fracture mechanics-based studies that have investigated this issue. In the present study, in vitro cyclic fatigue experiments were conducted over a range of cyclic frequencies (1-50 Hz) on elephant dentin in order to quantify fatigue-crack growth behavior from the ...

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