Notch fatigue behavior of needled C/SiC composite under random vibration loading

Author(s):  
Shao-Dong Wu ◽  
De-Guang Shang ◽  
Lin-Xuan Zuo ◽  
Lin-Feng Qu ◽  
Song-Guang Wang ◽  
...  
2014 ◽  
Vol 24 (5) ◽  
pp. 1331-1336 ◽  
Author(s):  
Hai-tao HU ◽  
Yu-long LI ◽  
Tao SUO ◽  
Feng ZHAO ◽  
Ying-gang MIAO ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1285
Author(s):  
Wentao He ◽  
Shaoping Wang ◽  
Chao Zhang ◽  
Xi Wang ◽  
Di Liu

The service life of mechanical face seals is related to the lubrication and wear characteristics. The stable analytical methods are commonly used, but they cannot address effects of random vibration loading, which, according to experimental studies, are important factors for lubrication and wear of mechanical face seals used in air and space vehicles. Hence, a dynamic model for mechanical face seals is proposed, with a focus on the effects of random vibration loading. The mechanical face seal in the axial direction is described as a mass-spring-damping system. Spectrum analysis specified for random vibration is then performed numerically to obtain the response power spectral density (PSD) of the mechanical face seal and calculate the root mean square (RMS) values under random vibration conditions. A lumped parameter model is then developed to examine how dynamic parameters such as stiffness and damping affect the lubrication regimes of mechanical face seals. Based on the dynamic model and Archard wear equation, a numerical wear simulation method is proposed. The results elucidated that the increase of input acceleration PSDs, the decrease of axial damping, and the increase of axial stiffness lead to the probability of the mechanical face seal operating under full film lubrication regime increase and finally the decrease of wear. This research provides a guideline for improving the adaptability of mechanical face seals under random vibration environments.


Author(s):  
Lyle Breaux ◽  
Scot McNeill ◽  
Gyorgy Szasz

A methodology is presented for Level 1 and 2 Fitness-for-Service (FFS) assessments of process and power piping subject to random vibration loading. The intent is to provide a basis for random vibration assessment based on concepts from spectral fatigue, which is simplified to the degree that a non-specialist can conduct the FFS assessment with little prior knowledge of the subject matter. The proposed Level 1 FFS assessment is based on extension and generalization of established industry screening curves for piping vibration. The measured (overall) RMS vibration level is compared against allowable values given by the curves evaluated at the average crossing frequency of the measured vibration. The proposed Level 2 FFS assessment utilizes an allowable cyclic stress. The allowable stress is a function of the target design life as well as the average crossing frequency and kurtosis of the measured vibration. Both approaches are illustrated by example.


2019 ◽  
Vol 95 ◽  
pp. 58-64 ◽  
Author(s):  
Jiang Xia ◽  
Lin Yang ◽  
Qunxing Liu ◽  
Qi Peng ◽  
LanXian Cheng ◽  
...  

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