On the thermal bending and twisting of thin skewed plates

1971 ◽  
Vol 73 (6) ◽  
pp. 306-312
Author(s):  
V. Puttaraju
Keyword(s):  
Thermal Bending ◽  
Skewed Plates

Structure-Based Huge Hard-Spring Torsional Resonator Coupled with Thermal Bending for Infrared Sensor

2020 ◽  
Vol 140 (9) ◽  
pp. 240-245
Author(s):  
Masaki Okamoto ◽  
Tomoya Hatagaki ◽  
Shinya Kumagai ◽  
Minoru Sasaki
Keyword(s):  
Infrared Sensor ◽  
Thermal Bending

Thermal bending and vibration of FGM plates with various cutouts and complex shapes using isogeometric method

2020 ◽  
pp. 113518
Author(s):  
Saifeng Zhong ◽  
Jianhua Zhang ◽  
Guoyong Jin ◽  
Tiangui Ye ◽  
Xiaoji Song
Keyword(s):  
Complex Shapes ◽  
Thermal Bending

A method to realize high-precision and large laser thermal bending angle

2021 ◽  
Vol 62 ◽  
pp. 168-178
Author(s):  
Yankuo Guo ◽  
Yongjun Shi ◽  
Xiaogang Wang ◽  
Rui Sun ◽  
Xianfa Li
Keyword(s):  
High Precision ◽  
Bending Angle ◽  
Thermal Bending

scholarly journals Study on Thermal Unstable Vibration of Rotor under Journal Whirl with Large Amplitude in Journal Bearing

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Qilong Hu ◽  
Min Zhu ◽  
Jiangang Yang
Keyword(s):  
Surface Temperature ◽  
Temperature Difference ◽  
Large Amplitude ◽  
Critical Speed ◽  
Journal Bearing ◽  
Lubricant Film ◽  
Analysis Model ◽  
Rotor Vibration ◽  
Thermal Bending ◽  
Unstable Vibration

To investigate the thermal unstable vibration caused by journal whirls with large amplitude in journal bearing, an analysis model of lubricant film thickness is established. The journal surface temperature distribution is solved, and the reason for journal surface temperature difference appearance and its influence on rotor vibration are analyzed. Taking a turbogenerator as an example, the journal surface temperature difference and the induced rotor thermal bending under synchronous whirl in the bearing are calculated. Meanwhile, an engineering vibration fault with its treatment is presented. Results show that, the journal surface circumferential temperature difference is caused by viscous shearing within lubricant film under journal whirls with large amplitude in journal bearing. The direction of temperature difference is related to the direction of unbalanced force acting on journal. The temperature difference causes rotor thermal bending, which can be converted to a thermal unbalance on the rotor. The rotor vibration is caused by both thermal and initial unbalance. When the rotor is running below or at the critical speed, the vibration is on the increase until it leads to instability of the rotor eventually. When the rotor is running above the critical speed, the rotor vibration fluctuates periodically. Reducing the initial (mechanical) unbalances decreases the rotor vibration and the journal surface circumferential temperature difference.

Some Effects of Start-Up and Shut-Down on Thrust Bearing Assemblies in Hydro-Generators

2003 ◽  
Vol 125 (4) ◽  
pp. 824-832 ◽  
Author(s):  
C. M. Ettles ◽  
J. Seyler ◽  
M. Bottenschein
Keyword(s):  
Thrust Bearing ◽  
Operating Conditions ◽  
Transient Effects ◽  
Design Studies ◽  
Thrust Bearings ◽  
Beneficial Effects ◽  
Start Up ◽  
Thermal Bending ◽  
Run Up ◽  
Basic Studies

The modernization of hydro-generators can involve the analysis of many different manufacturer’s designs of thrust bearings. Recent designs of bearing in common use are very reliable, but when failures do occur, it is often with older machines and within the first few minutes of start-up. This paper is a result of general design studies of various thrust bearing configurations subjected to transient operating conditions. It is shown that transient effects can induce an ‘overshoot’ of thermal deformation which can become unstable, leading to ‘thermal ratchetting.’ Examples are given of pads of various manufacturer’s bearings that have been subjected to this mechanism. Results from operating turbines, basic studies and measurements of the thermal bending of plates indicate that a peak deflection occurs well before thermal equilibrium is attained. The peaking phenomenon may be obscured in some designs or in cases where the run-up is gradual. The beneficial effects of using an oil-lift system during start-up are described. During shut-down it is important that the contact of hot, crowned pads against the runner be prevented. Minimum times for operation of the lift system are suggested, based on the thickness of the pads.

Thermal bending of plates with circular holes

1970 ◽  
Vol 14 (2) ◽  
pp. 231-238 ◽  
Author(s):  
R.E. Hoffman ◽  
T. Ariman
Keyword(s):  
Thermal Bending ◽  
Circular Holes
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