Active Control of Sound Radiated by a Submarine Hull in Axisymmetric Vibration Using Inertial Actuators

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Mauro Caresta ◽  
Nicole Kessissoglou
Keyword(s):  
Active Control ◽  
Structural Control ◽  
Single Point ◽  
Active Vibration Control ◽  
Axisymmetric Vibration ◽  
Sound Fields ◽  
Axial Forces ◽  
Submarine Hull ◽  
Acoustic Transfer Function ◽  
Control Forces

This paper investigates the use of inertial actuators to reduce the sound radiated by a submarine hull under excitation from the propeller. The axial forces from the propeller are tonal at the blade passing frequency. The hull is modeled as a fluid-loaded cylindrical shell with ring stiffeners and equally spaced bulkheads. The cylinder is closed at each end by circular plates and conical end caps. The forces from the propeller are transmitted to the hull by a rigid foundation connected to the propeller shaft. Inertial actuators are used as the structural control inputs. The actuators are arranged in circumferential arrays and attached to the internal end plates of the hull. Two active control techniques corresponding to active vibration control and discrete structural acoustic sensing are implemented to attenuate the structural and acoustic responses of the submarine. In the latter technique, error information on the radiated sound fields is provided by a discrete structural acoustic sensor. An acoustic transfer function is defined to estimate the far field sound pressure from a single point measurement on the hull. The inertial actuators are shown to provide control forces with a magnitude large enough to reduce the sound due to hull vibration.

Structural Control Considering Time Delay Effect

1985 ◽  
Vol 9 (4) ◽  
pp. 224-227 ◽  
Author(s):  
Mohamed Abdel-Rohman
Keyword(s):  
Time Delay ◽  
Active Control ◽  
Theoretical Consideration ◽  
Structural Control ◽  
Control Mechanism ◽  
Structural Response ◽  
Delay Effect ◽  
Numerical Example ◽  
Control Forces ◽  
Time Delay Effect

The time delay between measuring the structural response, and applying the designed active control forces may affect the controlled response of the structure if not taken into consideration. In this paper it is shown how to design the control forces to compensate for the delay effect. It is also shown that the time delay effect can be used as a criterion to judge the effectiveness of the proposed control mechanism. As an illustration of the theoretical consideration, a numerical example in which a tall building is controlled by means of active tendons is presented.

Semiactive Control of Structural Vibrations

1993 ◽  
Author(s):  
W. N. Patten ◽  
H. C. Wu ◽  
W. Yan ◽  
R. L. Sack ◽  
C. C. Kuo ◽  
...  
Keyword(s):  
Active Control ◽  
Structural Control ◽  
Control Strategies ◽  
Structural Response ◽  
Semiactive Control ◽  
Hydraulic Actuator ◽  
Limit States ◽  
Loop Control ◽  
Mechanical Devices ◽  
Control Forces

Abstract Structural control can be used to mitigate dynamic structural response and prevent structures from reaching their limit states. Typical active vibration systems utilize large electric motors, and expensive hydraulic pumping equipment to provide force inputs to a structure during a dynamic event. The work here explores the effectiveness of low power, inexpensive semi-active control hardware to provide vibration attenuation, for structures. While there are a number of electro-mechanical devices that might provide semi-active control forces, the investigation here analyzed the use of an automatically adjustable hydraulic actuator (i.e., a shock absorber). The variation in damping characteristics is accomplished by using variable orificing. While semi-active hydraulic actuators are a relatively cheap means of providing smart damping for a structure, the development of effective closed loop control strategies for these devices is not a completely resolved issue. The paper develops a dynamic model of a semi-active actuator. Two inner loop controllers are then suggested, for the operation of the actuator. The control of a simple structure is then simulated. The paper closes with a comparison of the performances between a semi-active (clipped optimal) control and active control of a three story structure that is subject to an earthquake.

Seismic Control Effect for Nonlinear Benchmark Building Using Passive or Semi-Active Damper

2002 ◽  
Author(s):  
Akira Fukukita ◽  
Tomoo Saito ◽  
Keiji Shiba
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Feedforward Control ◽  
Electrical Power ◽  
Control Device ◽  
Control Effect ◽  
Damping Force ◽  
Active Device ◽  
Seismic Control ◽  
Control Forces

We study the control effect for a 20-story benchmark building and apply passive or semi-active control devices to the building. First, the viscous damping wall is selected as a passive control device which consists of two outer plates and one inner plate, facing each other with a small gap filled with viscous fluid. The damping force depends on the interstory velocity, temperature and the shearing area. Next, the variable oil damper is selected as a semi-active control device which can produce the control forces by little electrical power. We propose a damper model in which the damping coefficient changes according to both the response of the damper and control forces based on an LQG feedback and feedforward control theory. It is demonstrated from the results of a series of simulations that the both passive device and semi-active device can effectively reduce the response of the structure in various earthquake motions.

The Semi-Active Control Considering Structure-Basement-Pile-Soil Interaction

2010 ◽  
Vol 163-167 ◽  
pp. 2780-2786
Author(s):  
Yan Tao Li ◽  
Zhan Xue Zhou
Keyword(s):  
Active Control ◽  
Structural Control ◽  
Soil Structure ◽  
Tall Buildings ◽  
Interaction System ◽  
Subdomain Method ◽  
Infinite Element Method ◽  
Fixed End ◽  
Instantaneous Optimal Control ◽  
The Impact

The interaction system which includes pi1e-supported tall buildings with multistoried basements and the adjacent medium of soil subject to the impact of earthquake is formulated in terms of the spline subdomain method,semi-analytical infinite element method and the bend-shear model of beam element,respectively.Taking advantage of the instantaneous optimal control algorithm, structure-basements-piles-soil interaction effect on the semi-active control is considered. It is shown that the results of structural control have obvious difference between the interaction system and the fixed-end system.The response of the former may be less about 10 percent than the latter in the paper.The dissipative capability of the structure self may be ignored largely if the interaction isn’t considered.When designing the system of the semi-active control, especially for some tall buildings,soil-structure interaction should be taken into consideration.

Frequency Shaped Semi-Active Control for Magnetorheological Fluid-Based Vibration Control Systems

2013 ◽  
Author(s):  
Young-Tai Choi ◽  
Norman M. Wereley ◽  
Gregory J. Hiemenz
Keyword(s):  
Vibration Control ◽  
Control Systems ◽  
Active Control ◽  
Control Algorithm ◽  
Active Vibration Control ◽  
Control Algorithms ◽  
Model Parameters ◽  
Mr Fluid ◽  
Control Current ◽  
Active Vibration

Novel semi-active vibration controllers are developed in this study for magnetorheological (MR) fluid-based vibration control systems, including: (1) a band-pass frequency shaped semi-active control algorithm, (2) a narrow-band frequency shaped semi-active control algorithm. These semi-active vibration control algorithms designed without resorting to the implementation of an active vibration control algorithms upon which is superposed the energy dissipation constraint. These new Frequency Shaped Semi-active Control (FSSC) algorithms require neither an accurate damper (or actuator) model, nor system identification of damper model parameters for determining control current input. In the design procedure for the FSSC algorithms, the semi-active MR damper is not treated as an active force producing actuator, but rather is treated in the design process as a semi-active dissipative device. The control signal from the FSSC algorithms is a control current, and not a control force as is typically done for active controllers. In this study, two FSSC algorithms are formulated and performance of each is assessed via simulation. Performance of the FSSC vibration controllers is evaluated using a single-degree-of-freedom (DOF) MR fluid-based engine mount system. To better understand the control characteristics and advantages of the two FSSC algorithms, the vibration mitigation performance of a semi-active skyhook control algorithm, which is the classical semi-active controller used in base excitation problems, is compared to the two FSSC algorithms.

Active Vibration Control of a Multimode Rotor-Bearing System Using an Adaptive Algorithm

1986 ◽  
Vol 108 (2) ◽  
pp. 230-231 ◽  
Author(s):  
A. V. Metcalfe ◽  
J. S. Burdess
Keyword(s):  
Active Vibration Control ◽  
Rotation Frequency ◽  
External Control ◽  
Electromagnetic Actuators ◽  
Mass Unbalance ◽  
Rotor Bearing ◽  
Active Vibration ◽  
Control Forces ◽  
Bearing System ◽  
Uncontrolled System

A method for minimizing forced harmonic vibration of a rotor-bearing system by the application of external control forces is presented. The frequency of the vibration is assumed known. In cases of mass unbalance or bend in the shaft this will be shaft rotation frequency and can usually be monitored without difficulty. The control forces could be provided by electromagnetic actuators. The control strategy presented does not require any knowledge of the system parameters and, provided the uncontrolled system is stable, cannot destablize the system. Results from a simulation are shown.

An Active-Passive Piezoelectric Vibration Absorber for Structural Control Under Harmonic Excitations With Time-Varying Frequency

2000 ◽  
Author(s):  
Ronald A. Morgan ◽  
K. W. Wang
Keyword(s):  
Active Control ◽  
Structural Control ◽  
High Performance ◽  
Piezoelectric Materials ◽  
Negative Resistance ◽  
Electrical Circuit ◽  
Superior Performance ◽  
Electrical Networks ◽  
Harmonic Excitations ◽  
Time Varying Frequency

Abstract It has been shown that piezoelectric materials can be used as passive electromechanical vibration absorbers when shunted by electrical networks. Semi-active piezoelectric absorbers have also been proposed for suppressing harmonic excitations with varying frequency. However, these semi-active devices have limitations that restrict their applications. The design presented here is a high performance active-passive alternative to semi-active absorbers that uses a combination of a passive electrical circuit and active control actions. The active control consists of three parts: an adaptive inductor tuning action, a negative resistance action, and a coupling enhancement action. A formulation for the optimal tuning of the piezoelectric absorber inductance on a multiple degree of freedom (MDOF) structure is derived. The effectiveness of the proposed system is demonstrated experimentally on a system under a variable frequency excitation. Extensive parameter studies are also carried out to show that the proposed design offers superior performance and efficiency compared to other state-of-the-art control methods.

scholarly journals Review on vibration control in tall buildings: from the perspective of devices and applications

2020 ◽  
Author(s):  
BG Kavyashree ◽  
Shantharam Patil ◽  
Vidya S. Rao
Keyword(s):  
Control System ◽  
Active Control ◽  
Structural Control ◽  
Passive Control ◽  
Hybrid Control ◽  
Tall Buildings ◽  
Effective Control ◽  
Earthquake Load ◽  
History Of ◽  
External Loads

AbstractPermanent construction has evolved from the Palaeolithic age to today’s skyscrapers. Constructing the structure, which promises occupants safety, has become a concern because of the uncertainties in nature. Therefore in recent years, attention has been given to the development of structural protective devices that could take care of the external loads. Structural control against the wind and earthquake load has been seriously studied where the structure behaves differently for wind and earthquake load has been briefly discussed in this paper. Initially, paper discusses the history of the construction and the passive control system, which was used in structural control, is briefly discussed in this paper. Also, the implementation of active control has been discussed which was introduced later in the structural control for more effective control. But the limitations of the passive and active control system have introduced semi-active control and also the hybrid control strategy. The two mechanisms are put together in the semi-active and hybrid system to obtain all advantages of the algorithm along with overcoming their limitations. The review also briefs about stochastic vibrational control of the structure where randomness is considered in external loads, parameter of the system and also in the external devices which are implemented in the structural control. As construction sector is a complex system, big data analysis, a new field in structural control system is discussed and future scope is also mentioned.

Sign in / Sign up

Export Citation Format

Share Document