Evaluation of an ultrasonic device to test fretting-fatigue in very high cycle regime
Traditional fatigue tests are not suitable for very high cycle fatigue (VHCF) problems,because of the enormous time spent to reach this regime.Many mechanical components may,however,be subjected to VHCF.Fatigue strength beyond certain limit is usually estimated using statistical approaches or establishing a threshold for crack nucleation.Fretting may take place whenever two fixed parts are under mechanical vibration and variable bulk load.It can have catastrophic effects for parts under fatigue,mainly in VHCF,virtually eliminating crack initiation period.The objective of the present work was to evaluate an ultrasonic device to accelerate very high cycle frettingfatigue tests.Axial load was imposed by a piezoelectric transducer to round cross-section specimens.Fretting was induced by forcing at right angle cylinder pads,which were replaceable and could be specified for each case.It was possible to choose,at the same time,both fretting amplitude and bulk load.Normal load was imposed by an adjustable spring.Results confirmed that fatigue strength decreased significantly when specimens were subjected to fretting.Besides this,worn surfaces showed many characteristics evidencing the occurrence of fretting.Upgrades are necessary to decrease the influence of the apparatus on fretted amplitude and to facilitate surfaces alignment.
high cycle fatigue fretting-fatigue ultrasonic fatigue testing
Pedro F.Filgueiras Claude Bathias Ernani S.Palma
Department of Mechanical Engineering,Universidade Federal de Minas Gerais,Belo Horizonte 31270-901,B Laboratoire Energétique Mécanique Electromagnétisme,Université Paris Ouest,Ville d’Avray 92410,Franc
国际会议
北京
英文
1-10
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）