Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (6)

Search Parameters:
Keywords = external horizontal damping

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
18 pages, 5328 KiB  
Article
Theoretical and Experimental Investigation of Dynamic Characteristics in Propulsion Shafting Support System with Integrated Squeeze Film Damper
by Qilin Liu, Wu Ouyang, Gao Wan and Gaohui Xiao
Lubricants 2025, 13(8), 335; https://doi.org/10.3390/lubricants13080335 - 30 Jul 2025
Viewed by 106
Abstract
The lateral vibration of propulsion shafting is a critical factor affecting the acoustic stealth performance of underwater vehicles. As the main vibration isolation component in transmitting vibrational energy, the damping efficiency of the propulsion shafting support system (PSSS) holds particular significance. This study [...] Read more.
The lateral vibration of propulsion shafting is a critical factor affecting the acoustic stealth performance of underwater vehicles. As the main vibration isolation component in transmitting vibrational energy, the damping efficiency of the propulsion shafting support system (PSSS) holds particular significance. This study investigates the dynamic characteristics of the PSSS with the integral squeeze film damper (ISFD). A dynamic model of ISFD–PSSS is developed to systematically analyze the effects of shaft speed and external load on its dynamic behavior. Three test bearings (conventional, 1S, and 3S structure) are designed and manufactured to study the influence of damping structure layout scheme, damping fluid viscosity, unbalanced load, and shaft speed on the vibration reduction ability of ISFD–PSSS through axis orbit and vibration velocity. The results show that the damping effects of ISFD–PSSS are observed across all test conditions, presenting distinct nonlinear patterns. Suppression effectiveness is more pronounced in the vertical direction compared to the horizontal direction. The 3S structure bearing has better vibration reduction and structural stability than other schemes. The research results provide a reference for the vibration control method of rotating machinery. Full article
(This article belongs to the Special Issue Water Lubricated Bearings)
Show Figures

Figure 1

23 pages, 6630 KiB  
Article
Investigation into the Dynamic Parameter Characterization of Water-Lubricated Bearings Under Vibration Coupling
by Hongtao Zhu, Yong Jin, Qilin Liu, Wu Ouyang and Tao He
Lubricants 2025, 13(3), 123; https://doi.org/10.3390/lubricants13030123 - 14 Mar 2025
Cited by 1 | Viewed by 516
Abstract
This study aims to investigate the dynamic behavior of water-lubricated stern bearings during service. A transient rotor dynamics numerical model is developed to research the effects of operating conditions and critical structural parameters on the variation patterns of the dynamic characteristic coefficients and [...] Read more.
This study aims to investigate the dynamic behavior of water-lubricated stern bearings during service. A transient rotor dynamics numerical model is developed to research the effects of operating conditions and critical structural parameters on the variation patterns of the dynamic characteristic coefficients and journal orbit of WLBs. The main stiffness and damping formulas for dimensionless bearings are fitted based on numerical results. Additionally, the accuracy of the model calculations is experimentally verified on a water-lubricated bearing test rig. The results demonstrate that the variation trends of the main stiffness and main damping coefficients in the horizontal and vertical directions of the bearings are proportional to the external load and inversely proportional to the rotational speed. Under eccentric excitation, the dynamic characteristic coefficients of the bearings change periodically with time as an approximately sinusoidal function. With the increase in the bearing length-to-diameter ratio or the decrease in the radial clearance-to-radius ratio, the main stiffness and the main damping coefficients in the horizontal direction increase, while the main stiffness coefficient in the vertical direction decreases. This study provides theoretical support for modeling the transient transverse vibration of a propulsion shaft system. Full article
(This article belongs to the Special Issue Friction–Vibration Interactions)
Show Figures

Figure 1

22 pages, 5778 KiB  
Article
Identification of Dynamic Parameters and Frequency Response Properties of Active Hydraulic Mount with Oscillating Coil Actuator: Theory and Experiment
by Rang-Lin Fan and Zhen-Nan Fei
Appl. Sci. 2022, 12(17), 8547; https://doi.org/10.3390/app12178547 - 26 Aug 2022
Cited by 4 | Viewed by 1566
Abstract
Active hydraulic mounts (AHMs) provide an effective solution for refining ride comfort noise and vibration in passenger cars. AHMs with inertia tracks, decoupler membranes, and oscillating coil actuators (AHM-IT-DM-OCAs) have been extensively studied owing to their compact structures and strong damping characteristics in [...] Read more.
Active hydraulic mounts (AHMs) provide an effective solution for refining ride comfort noise and vibration in passenger cars. AHMs with inertia tracks, decoupler membranes, and oscillating coil actuators (AHM-IT-DM-OCAs) have been extensively studied owing to their compact structures and strong damping characteristics in the low-frequency band. This study focuses on the full parameter identification based on the distinct features of external dynamics, which can be used to obtain an accurate and reliable estimate of the transfer functions required for active control algorithms. A lumped parameter model was established for the AHM-IT-DM-OCAs, and the analytical frequency bands were defined by the two resonance frequencies of the fluid channel and actuator mover. Methods for nonlinear model simplification were proposed in different bands and verified theoretically. Based on the simplified models, the distinct features of the active and passive dynamics are successively revealed, which include three resonances and seven horizontal segments. Subsequently, a series of experimental studies on the distinct features were carried out, which agreed well with the theoretical results. However, owing to the limitations of the test equipment and fixture modalities, only the distinct features of one fixed point, two resonance peaks, and three horizontal segments can be used for parameter identification. Based on the validated distinct features, a procedure for full parameter identification is proposed, and all six key parameters are identified. The obtained results showed good consistency and rationality, indicating that this approach can be used for the transfer function estimation of the primary and secondary paths of the AHM-IT-DM-OCAs. Full article
(This article belongs to the Section Acoustics and Vibrations)
Show Figures

Figure 1

17 pages, 5221 KiB  
Article
Enhancing Output Power of a Cantilever-Based Flapping Airflow Energy Harvester Using External Mechanical Interventions
by Liuqing Wang and Dibin Zhu
Sensors 2019, 19(7), 1499; https://doi.org/10.3390/s19071499 - 28 Mar 2019
Cited by 8 | Viewed by 3569
Abstract
This paper presents a flapping airflow energy harvester based on oscillations of a horizontal cantilever beam facing the direction of airflow. A wing is attached to the free end of a cantilever beam and a bluff body is placed in front of the [...] Read more.
This paper presents a flapping airflow energy harvester based on oscillations of a horizontal cantilever beam facing the direction of airflow. A wing is attached to the free end of a cantilever beam and a bluff body is placed in front of the wing from where vortex falls off, producing vortices under the wing and driving it to oscillate. An electromagnetic transducer is integrated to convert the flow induced vibration into electrical energy. This flapping energy harvester, however, may stop oscillating or vibrate in the second mode under high electrical damping, and thus may be unable to achieve its optimum performance. Simple yet effective mechanical interventions can be applied to the harvester to enhance its power output, i.e., to increase flow velocity and to apply external magnetic interaction. The effect of airflow velocities on output power was investigated experimentally and the results show that the energy harvester scavenges more power in airflow at higher Reynolds numbers (higher flow velocity at R e < 24,000). The external magnetic excitation is achieved though placing one magnet to the wing and another one above the wing to induce a repelling force, aiding the beam to oscillate in high electrical damping. Experimental results show that the power output can be enhanced by 30% when the magnet interaction is properly integrated. Full article
(This article belongs to the Special Issue Energy Harvesting Sensor Systems)
Show Figures

Figure 1

20 pages, 15529 KiB  
Article
Simulation and Experimental Studies of a Multi-Tubular Floating Sea Wave Damper
by Leszek Chybowski, Zenon Grządziel and Katarzyna Gawdzińska
Energies 2018, 11(4), 1012; https://doi.org/10.3390/en11041012 - 20 Apr 2018
Cited by 16 | Viewed by 4928
Abstract
This article explores the issue of shore protection from sea waves and has presented the main methods used for coastal protection. It discusses the construction and operation of the multi-tubular floating sea wave damper that has been developed at the Maritime University of [...] Read more.
This article explores the issue of shore protection from sea waves and has presented the main methods used for coastal protection. It discusses the construction and operation of the multi-tubular floating sea wave damper that has been developed at the Maritime University of Szczecin by Professor Bolesław Kuźniewski. This paper presents the results of the research project aimed at creating and examining a prototype of the device. The research aimed to confirm the two hypotheses: “the largest damping force should occur when the damping units are placed at an optimal distance equal to half the length of the wave to be damped” and “a compensation of the horizontal forces caused by the rippling of water should occur in the damping device”. Simulation studies of the behaviour of the device’s buoyancy elements when floating on waves were performed using the ANSYS AQWAWB and AQWA software. The buoyancy components were modelled as TUBE elements with a diameter of 0.11 m and a length of 1.5 m and as triangular and square surface elements. The results of the experimental research and the computer simulation of the operation of the prototype device have also been presented. The external conditions adopted corresponded to the frequency of a wave equal to 0.807 Hz and to the wave height in front of the device which was equal to 0.1 m. Experimental studies were conducted in an auxiliary model basin with dimensions of 60 m × 7 m × 3.12 m at the Ship Hydromechanics Division, Ship Design and Research Centre (CTO S. A.) in Gdańsk (Poland). The study recorded the distribution of the vertical and horizontal forces acting on the prototype device as well as the wave height both in front of and behind the device. Both hypotheses were proven. Simulation and experimental studies have been summarised. A proposal for future works has also been presented. Full article
Show Figures

Figure 1

17 pages, 3824 KiB  
Article
An Adaptive Damping Network Designed for Strapdown Fiber Optic Gyrocompass System for Ships
by Jin Sun, Xiaosu Xu, Yiting Liu, Tao Zhang, Yao Li and Jinwu Tong
Sensors 2017, 17(3), 494; https://doi.org/10.3390/s17030494 - 2 Mar 2017
Cited by 20 | Viewed by 5564
Abstract
The strapdown fiber optic gyrocompass (strapdown FOGC) system for ships primarily works on external horizontal damping and undamping statuses. When there are large sea condition changes, the system will switch frequently between the external horizontal damping status and the undamping status. This means [...] Read more.
The strapdown fiber optic gyrocompass (strapdown FOGC) system for ships primarily works on external horizontal damping and undamping statuses. When there are large sea condition changes, the system will switch frequently between the external horizontal damping status and the undamping status. This means that the system is always in an adjustment status and influences the dynamic accuracy of the system. Aiming at the limitations of the conventional damping method, a new design idea is proposed, where the adaptive control method is used to design the horizontal damping network of the strapdown FOGC system. According to the size of acceleration, the parameters of the damping network are changed to make the system error caused by the ship’s maneuvering to a minimum. Furthermore, the jump in damping coefficient was transformed into gradual change to make a smooth system status switch. The adaptive damping network was applied for strapdown FOGC under the static and dynamic condition, and its performance was compared with the conventional damping, and undamping means. Experimental results showed that the adaptive damping network was effective in improving the dynamic performance of the strapdown FOGC. Full article
(This article belongs to the Section Physical Sensors)
Show Figures

Figure 1

Back to TopTop