The effects of the effective support length of the stern bearing on ship shafting vibration transmission paths

2016 ◽  
pp. 143-148
Keyword(s):  
Vibration Transmission ◽  
Support Length

Estimating vibration transmission characteristics in tooth roots: A study.

1987 ◽  
Vol 31 (4) ◽  
pp. 907-915
Author(s):  
Eiichi Hanzawa ◽  
Hideaki Takehana ◽  
Akira Kimura ◽  
Minoru Toyoda ◽  
Etsuro Matsuo
Keyword(s):  
Transmission Characteristics ◽  
Vibration Transmission ◽  
Tooth Roots

scholarly journals Study on the additional support length requirements of single-span bridges due to skew using a simplified method

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Suiwen Wu ◽  
Junfeng Jia ◽  
Chiyu Jiao ◽  
Junfei Huang ◽  
Jianzhong Li
Keyword(s):  
Aspect Ratio ◽  
Response Spectrum ◽  
Skew Angle ◽  
Empirical Formulas ◽  
Design Response Spectrum ◽  
Skew Bridges ◽  
Simplified Method ◽  
Additional Support ◽  
Linear Manner ◽  
Support Length

AbstractSkew bridges with seat-type abutments are frequently unseated in earthquakes due to large transverse displacements at their acute corners. It is believed these large displacements are due to in-plane rotation of the superstructure. Lack of detailed guidelines for modeling of skew bridges, many current design codes give empirical expressions rather than theoretical solutions for the additional support length required in skew bridges to prevent unseating. In this paper, a parametric study has been carried out to study the influence of skew angle, aspect ratio and fundamental periods of bridges on the additional support length requirements of single-span bridges due to skew using a shake table experiment validated Simplified Method, which is capable of simulating gap closure based on response spectrum analysis. This method is developed based on the premise that the obtuse corner of the superstructure engages the adjacent back wall during lateral loading and rotates about this corner until the loading reverses direction. A design response spectrum specified in AASHTO LRFD Specifications was employed to represent the design-level earthquakes. The results show the additional length required to prevent unseating due to skew increases with the skew angle in an approximately linear manner when the angle is less than a critical value and decreases for angles above this value. This critical skew angle increases with the aspect ratio approximately in a linear manner and shows negligible dependence on the fundamental periods of the bridges, and combination of span length and width. In addition, the critical skew angle varies between 58° and 66°, when the aspect ratio is varied from 3.0 to 5.0. The results also show that the empirical formulas for minimum support length requirements of skew bridges in current codes and specifications can not accurately reflect the influence of skew.

scholarly journals Study on Vibration Transmission among Units in Underground Powerhouse of a Hydropower Station

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3015 ◽  
Author(s):  
Jijian Lian ◽  
Hongzhen Wang ◽  
Haijun Wang
Keyword(s):  
Low Frequency ◽  
Field Tests ◽  
Vertical Vibration ◽  
Transmission Mechanism ◽  
Structural Vibration ◽  
Hydropower Station ◽  
Fe Model ◽  
Vibration Transmission ◽  
Underground Powerhouse ◽  
Mechanical Models

Research on the safety of powerhouse in a hydropower station is mostly concentrated on the vibration of machinery structure and concrete structure within a single unit. However, few studies have been focused on the vibration transmission among units. Due to the integrity of the powerhouse and the interaction, it is necessary to study the vibration transmission mechanism of powerhouse structure among units. In this paper, field structural vibration tests are conducted in an underground powerhouse of a hydropower station on Yalong River. Additionally, the simplified mechanical models are established to explain the transmission mechanism theoretically. Moreover, a complementary finite element (FE) model is built to replicate the testing conditions for comprehensive analysis. The field tests results show that: (1) the transmission of lateral-river vibration is greater than those of longitude-river vibration and vertical vibration; (2) the vibration transmission of the vibrations that is caused by the low frequency tail fluctuation is basically equal to that of the vibrations caused by rotation of hydraulic generator. The transmission mechanism is demonstrated by the simplified mechanical models and is verified by the FE results. This study can provide guidance for further research on the vibration of underground powerhouse structure.

Vibration Transmission Between Columns and Built Up Structures

1994 ◽  
Vol 1 (3) ◽  
pp. 235-246
Author(s):  
John A. Steel
Keyword(s):  
Sound Transmission ◽  
Transmission Characteristics ◽  
Vibration Transmission ◽  
Laboratory Models ◽  
Good Agreement

Vibration transmission from columns into built up structures is studied using laboratory models. Beams attached to plates, forming built up structures, can influence transmission characteristics at these joints. Good agreement is found between measured and predicted results. The orientation of the beams effects coupling and strongest coupling is through a twisting moment applied to the beam. The effects of these changes in coupling on sound transmission between floors is discussed.

Sign in / Sign up

Export Citation Format

Share Document