This paper is concerned with the analysis of active and passive hybrid actions in structures constrained damping layers (ACL). A system model derived via Hamilton’s Principle, based on constitutive equations elastic, viscoelastic, piezoelectric materials. The converges to a purely piezotronic as thickness viscoelastic material (VEM) layer approaches zero. mixed Galerkin-GHM (Golla-Hughes-McTavish) method employed discretize analyze time domain. With an LQR (linear quadratic regulator)...

Extensive investigations have been conducted to study the vibration localization phenomenon and excessive forced response that can be caused by mistuning in bladed disks. Most previous researches focused on analyzing∕predicting or attacking issue via mechanical tailoring. Few developing effective control methods for such systems. This extends piezoelectric network concept, which has utilized mode delocalization periodic structures, of mistuned disks under engine order excitation. A is...

Abstract Virtual coupling is a novel technology that enables trains to run closely together without physical connections through communication and automation systems. The paper addresses an adaptive polynomial approximation algorithm for cooperative control of high-speed (HSTs) under virtual coupling. It aims solve the tracking problem HSTs formation operations various scenarios, including known unknown parameters. To enable system achieve operation while ensuring appropriate spacing...

Understanding the instability phenomena of rotor-shaft and driveline systems incorporating universal joints is becoming increasingly important because trend towards light-weight, high-speed supercritical designs. In this paper, a nondimensional, periodic, linear time-varying model with torsional lateral degrees-of-freedom developed for rotor shaft-disk assembly supported on flexible bearing driven through U-joint. The stability system investigated utilizing Floquet theory. It shown that...

This paper explores the feasibility of using Magnetorheological (MR) fluid-based dampers for lag damping augmentation in helicopters. An MR damper model is integrated with a rotor aeromechanical model. Two different control schemes are presented-namely On-Off scheme and Feedback Linearization scheme. In scheme, two criteria used to obtain equivalent linear nonlinear as function size perturbation applied field. The uses feedback controller linearize force output damper. compared transient...

The underlying principle for vibration confinement is to alter the structural modes so that corresponding modal components have much smaller amplitude in concerned area than remaining part of structure. In this research, state-of-the-art technique advanced two correlated ways. First, a new eigenstructure assignment algorithm developed more directly suppress regions interest. This featured by optimal selection achievable eigenvectors minimizes eigenvector at region using Rayleigh Principle....

Extremely large, lightweight, in-space deployable active and passive microwave antennas are demanded by future space missions. This paper investigates the development of PVDF based piezopolymer actuators for controlling surface accuracy a membrane reflector. Uniaxially stretched films were poled using an electrodeless method which yielded high quality piezofilms required this applications. To further improve piezoperformance piezopolymers, several copolymers examined. It was found that one...

This paper proposes a multi-mode vibration suppression scheme for rotationally periodic structures. Identical active-passive hybrid piezoelectric networks are applied on each of the substructures, where active charge and current feedback is used together with passive shunts to optimize network performance. By exploiting rotational periodicity, new algorithm synthesized analytically determine control parameters. It shown that this approach can suppress all spatial harmonics, which cannot be...

This paper is concerned with the enhanced active constrained layer (EACL) damping treatment edge elements. A finite element time-domain-based model (FEM) developed for beam structure partially covered EACL. The elements are modeled as equivalent springs mounted at boundaries of piezoelectric layer. Golla-Hughes-McTavish (GHM) method used to viscoelastic GHM dissipation coordinates can describe frequency-dependent material properties. becomes current (ACL) system stiffness approaches zero....

It is known that, when the mechanical coupling between substructures weak, small imperfections in a periodic structure can induce vibration localization. This phenomenon could lead to large certain regions of and be very harmful system. In this study, it shown that proposed coupled piezoelectric circuits greatly relieve or even eliminate such localization problems. Part structural energy will transferred into electrical through materials, newly created electro-mechanical wave/energy channel...

A structural vibration control concept, using piezoelectric materials shunted with real-time adaptable electrical networks, has been investigated. The variable resistance and inductance in an external RL circuit are used as inputs. An energy-based parametric scheme is created to reduce the total system energy (the main structure mechanical plus energies of material circuit) while minimizing flowing into structure. Stability closed-loop proved. performance controller examined through...

The concept of using sensitivity-enhancing feedback control to improve the performance frequency-shift-based structural damage identification has been recently explored. In previous studies, however, controller is designed alter only closed-loop eigenvalues, and effect eigenvectors on sensitivity enhancement not considered. this research, it shown that natural frequency shift in a multi-degree-of-freedom structure can be significantly influenced by placement both eigenvalues eigenvectors. A...

It has been shown that piezoelectric materials can be used as passive electromechanical vibration absorbers by shunting them with electrical networks. Semi-active have also proposed for suppressing harmonic excitations varying frequency. However, these semi-active devices limitations restrict their practical applications. The approach presented here is a high performance active-passive alternative to absorbers. By utilizing combination of circuit and active control actions, the system...

Experimental evidence (Shin, 1992) has shown that the natural frequencies of high-speed spindles with angular contact ball bearings decrease increasing rotational speed. A recent study (Wang et al., 1991) illustrated this phenomenon is caused by stiffness change bearings. simplified approximation was used in past analysis to examine bearing radial at high speeds. While investigation explained experimental observations a qualitative sense, analytical results so far are not sufficient...

Advanced driving algorithms, control strategies, and their optimization in self-driving vehicles various scenarios are hotspots current research; 4WS-4WD (four-wheel steering four-wheel drive) is another hotspot the study of new concept models; nonlinear dynamic characteristics (AVs) prominent fast cornering mode, which leads to a significant reduction accuracy stability trajectory tracking. Based on these research backgrounds, this paper proposes strategy idea based 4WS4WD vehicle its...

A considerable amount of work has been performed in recent years to utilize piezoelectric materials for semiactive and active-passive hybrid structural damping. Many interesting phenomena have studied, promising results shown. For damping, most the investigations focused on designing control actions switch or vary electrical components networks. two schools thought examined. One is use active passive features simultaneously exercise The other integrate with traditional damping into a...

In this research, a new hybrid neural network is developed to model engagement behaviors of automotive transmission wet friction component. Utilizing known first principles on the physics engagement, special modules are created estimate viscous torque and asperity contact as preprocessors two-layer network. Inside these modules, all physical parameters represented by neurons with various activation functions derived from principles. These features contribute improved performance trainability...

This article presents a model for describing the damping characteristics of uniaxially stressed polymeric composites filled with randomly oriented single-wall nanotube (SWNT) ropes. A close-packed lattice consisting seven nanotubes in hexagonal array is used to present nanoropes. The composite described as three-phase system composed resin, resin sheath acting shear transfer zone, and SWNT concept ‘stick-slip’ motion caused by frictional contacts proposed describe load behavior between...

An energy-based algorithm is developed for dynamic absorbers with adaptable stiffness to suppress structural vibrations via real-time parametric control actions. A controller multi-objective fuzzy logic created reduce the main structure energy while constraining total system energy. To ensure stability, an adaptive-passive supervisor designed provide guidelines implementing law. It proved that using this globally stable in sense all signals involved are bounded. The performance of...

This paper presents an integrated study of a rotor/bearing structure, with specific interests toward high-speed spindle systems under rotating end loads. Considering the coupling between shaft and nonlinear bearings, iterative method is developed to derive system equilibrium configuration for given operating conditions. With moving loads, structural instability caused by high rotational speed analyzed. The critical speeds unstable regions are discussed. Machining chatter lobes also derived...

Piezoelectric stacks can normally take significant compressive loads but cannot tolerate tension. Therefore, conventional piezoelectric stack actuators are mainly designed for the push-only actions and usually incorporate a preload mechanism to protect from experiencing tensile stresses. A common method is include mechanical spring in parallel with stack, which may reduce free stroke capability of actuator affect performance. In this research, new bi-directional (can operate both push pull...