scholarly journals Experimental Research on the Vibration of Ship Propulsion Shaft under Hull Deformation Excitations on Bearings

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Cong Zhang ◽  
Dongchen Xie ◽  
Qianwen Huang ◽  
Zhihua Wang
Keyword(s):  
Resonant Frequency ◽  
Experimental Research ◽  
Dynamic Characteristics ◽  
Rotation Speed ◽  
Experimental System ◽  
Coupling Vibration ◽  
Safety And Reliability ◽  
Shaft Vibration ◽  
Dynamic Excitations ◽  
Ship Vibration

With the development of ship enlargement, the problems of coupling vibration between hull and propulsion system and vibration transmission via bearings are more and more prominent. Based on the theory of shaft vibration and the experimental system for dynamic characteristics of the shaft, an experiment plan about propulsion shaft vibration under dynamic excitations is designed in this paper. The performance of propulsion shaft vibration under hull deformation excitations applied on intermediate and stern bearings is studied. Hydraulic excitations in horizontal and vertical directions on the intermediate bearing and stern bearing of the experimental model of propulsion shaft are considered in this paper to simulate hull deformation on bearings of the ship. Vibration characteristics of the shaft under different excitations are gained and coupling effects are discussed. Moreover, the influences of amplitude and direction of excitations on bearings and the shaft rotation speed on the vibration of propulsion are studied. The results show that aiming at improving the safety and reliability of navigation, the hull deformation, especially the horizontal hull deformation excitation on the intermediate bearing, is not neglectable and should be considered during primary design. Also, rotation speed and resonant frequency are needed to be well designed with the frequencies of hull deformation excitations.

scholarly journals Analysis of the dynamic characteristics of downsized aerostatic thrust bearings with different pressure equalizing grooves at high or ultra-high speed

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110180
Author(s):  
Ruzhong Yan ◽  
Haojie Zhang
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Rotation Speed ◽  
Dynamic Stiffness ◽  
Simulation Method ◽  
Perturbation Amplitude ◽  
Thrust Bearings ◽  
Supply Pressure ◽  
Ultra High Speed ◽  
Air Film

This study adopts the DMT(dynamic mesh technology) and UDF(user defined functions) co-simulation method to study the dynamic characteristics of aerostatic thrust bearings with equalizing grooves and compare with the bearing without equalizing groove under high speed or ultra high speed for the first time. The effects of air film thicness, supply pressure, rotation speed, perturbation amplitude, perturbation frequency, and cross section of the groove on performance characteristics of aerostatic thrust bearing are thoroughly investigated. The results show that the dynamic stiffiness and damping coefficient of the bearing with triangular or trapezoidal groove have obvious advantages by comparing with that of the bearing without groove or with rectangular groove for the most range of air film thickness, supply pressure, rotation speed, perturbation amplitude, especially in the case of high frequency, which may be due to the superposition of secondary throttling effect and air compressible effect. While the growth range of dynamic stiffness decreases in the case of high or ultra-high rotation speed, which may be because the Bernoulli effect started to appear. The perturbation amplitude only has little influence on the dynamic characteristic when it is small, but with the increase of perturbation amplitude, the influence becomes more obvious and complex, especially for downsized aerostatic bearing.

scholarly journals Assessment of Bearing Dynamic Characteristics by Numerical Modeling with Effects of Oil Film and Centrifugal Deformation

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Jie Yu ◽  
Wei Yuan ◽  
Songsheng Li ◽  
Wenbing Yao
Keyword(s):  
Contact Angle ◽  
Dynamic Characteristics ◽  
Axial Load ◽  
Rotation Speed ◽  
Great Influence ◽  
Static Model ◽  
Contact Load ◽  
Oil Film ◽  
Spindle Bearing ◽  
Ring Rotation

This paper developed a modified quasi-static model (MQSM), considering the oil film thickness between the bearing parts and the centrifugal deformation of the inner ring, and contrasting with traditional quasi-static model (TQSM), to analyze the dynamic characteristics of spindle bearing. The model was verified with the experimental results. A systematic parametric analysis was made to investigate the influence of applied load, inner ring rotation speed (ni), and the radius coefficient of groove curvature (RCR) on the contact load, contact angle, and heat generating rate. The results show that there is a smaller influence on the contact load, contact angle, and heat generation of bearing with the changes of ni and axial load (Fa) of bearing in the case of MQSM and TQSM. But the radial load (Fr) and RCR have great influence on this.

Experimental Research on Rotating Skimmer

2003 ◽  
Author(s):  
Minoru Chino ◽  
Kenji Takizawa ◽  
Takashi Yabe
Keyword(s):  
Experimental Research ◽  
Rotational Speed ◽  
Rotation Speed ◽  
Experimental Results ◽  
Injection System ◽  
Benchmark Test ◽  
Injection Speed ◽  
Structure Interaction ◽  
Wide Range ◽  
Computer Codes

This paper provides the experimental results on skimmer and gives some detailed information useful for benchmark test of computer codes that are now able to simulate the fluid-structure interaction. For this purpose, we specially designed the injection system that imposes reproducible rotational speed and injection speed on the skipper. The effect of rotation is discussed by changing rotation speed in a wide range.

Study on the influence of machine tool spindle radial error motion resulted from bearing outer ring tilting assembly

2018 ◽  
Vol 233 (9) ◽  
pp. 3246-3258 ◽  
Author(s):  
Xiaohu Li ◽  
Ke Yan ◽  
Yifa Lv ◽  
Bei Yan ◽  
Lei Dong ◽  
...  
Keyword(s):  
Rotation Speed ◽  
Total Error ◽  
Experimental System ◽  
Outer Ring ◽  
Operation Condition ◽  
Thermal Displacement ◽  
Radial Error ◽  
Spindle Rotation ◽  
Motion Characteristics ◽  
Error Motion

To reveal the spindle radial error motion characteristics in condition of bearing outer ring tilting assembly, mathematical method on spindle radial error motion were analyzed. Then, in real operation condition the natural frequency of the test rig was investigated. Experimental system and methods were designed to test axial thermal displacement, radial error motion and modal characteristic of spindle in condition of bearing outer ring tilting assembly. Results show that axial thermal extension and radial vertical rising of spindle front-end occurs during thermal displacement test. With the same outer spacer nonparallelism, the synchronous error motion and total error motion generally increase with spindle rotation speed, and reach a peak at certain rotation speed.

Experimental Research on Dynamic Characteristics of a Rolling Agricultural Tire (Influence of Running Condition)

2013 ◽  
Author(s):  
Katsuhide Fujita ◽  
Takashi Saito ◽  
Mitsugu Kaneko
Keyword(s):  
Natural Frequency ◽  
Dynamic Behavior ◽  
Experimental Research ◽  
Dynamic Characteristics ◽  
Excitation Frequency ◽  
Road Surface ◽  
Natural Mode ◽  
The Road ◽  
On The Road ◽  
Agricultural Machines

When agricultural machines are operated on pavements, the vibration and noise caused by the interaction between the tire lugs and the road surface are inevitable. In conventional studies, it is considered that the dynamic behavior of a rolling agricultural tire is influenced by the vibration characteristics of the tire. Resonance occurs when the lug excitation frequency of the tire, which is defined as the lug number multiplied by the number of revolutions of the tire, becomes equal to the natural frequency of the tire. In other words, the rolling tire shows large vibrations in the direction of the natural mode corresponding to the natural frequency of the tire. However, in the conventional equipment, the diameter of the drum is smaller than that of the tire. Therefore, the real running condition on the road was not realized by the rolling test using the conventional equipment. In this study, a new equipment is produced to realize the running condition in the rolling test. The dynamic and vibratory characteristics of operating agricultural machine are investigated by using this new equipment. The obtained results are compared to the conventional ones and the influence of the running condition on dynamic characteristics of rolling tire is investigated.

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