Design Of Isolation System Research Articles

Study on Dynamic Characteristics of Resilient Mount Under Preload.

Resilient mounts are essential for anti-vibration and shock absorption applications, making accurate predictions of their static and dynamic behaviors critical for effective design and mechanical performance. This study investigates static and dynamic characteristics of resilient mounts to predict their effects. Tension, compression, and shear tests were performed under quasi-static loading conditions to obtain stress-strain cycle curves. This study includes a review of the Yeoh hyperelastic model, which consists of three parameters, and discusses the calibration of these parameters to describe the hyperelastic material behavior. The parameters were validated through numerical analysis by comparing them with experimental results from quasi-static tests on the resilient mount. The dynamic behavior was further analyzed using modal analysis and frequency response simulations under various preload conditions. Results show that increasing preload significantly shifts the transmissibility curves and resonance peaks to lower frequencies. This study offers valuable insights into static and dynamic characteristics of resilient mounts, contributing to the design and optimization of vibration isolation systems for naval applications.

Study of Systems of Active Vibration Protection of Navigation Instrument Equipment

Assessment of the influence of vibration isolator parameters on the distribution of the system’s natural frequencies is a significant task in the design of vibration isolation systems. The root method was used to determine the natural frequencies of the controlled vibration isolator. For a certain feedback structure of a controlled electrodynamic type vibration isolator, the need for a consistent selection of parameters has been justified. A mathematical solution has been proposed for the approximate determination of the roots of the characteristic equation of the controlled vibration isolator, which enables the analytical assessment of the influence of the vibration isolator parameters on the distribution of its natural frequencies. The research has been conducted in relative parameters, which makes it possible to generalize the results. The specificity of the inertial dynamic vibration isolator, which in some cases is associated with the implementation of anti-resonance conditions, can lead to the fact that resonant frequencies can occur on both sides of the tuning frequency of the vibration isolator. The use of an elastic suspension on flat springs to protect navigation equipment from vibration allows reduction in the intensity of translational vibration, while not changing the orientation of the device relative to the Earth. The implementation of an elastic suspension according to the scheme of the inverted pendulum allows an increase in the effectiveness of vibration isolation, under the conditions of a controlled change of the vibration isolator parameters and due to the use of feedback. The results of this research can be used in precision systems, such as vibration isolators, laser processing equipment, ultraprecision measurements or medical devices.

Optimum Design of Elastomer-Based Shock Isolation System for a Naval Component

Optimum Design of Elastomer-Based Shock Isolation System for a Naval Component

Design and mechanical properties of metal rubber secondary multidirectional vibration isolation system under random vibration

Design and mechanical properties of metal rubber secondary multidirectional vibration isolation system under random vibration

Damping performance and optimal design of mid-story isolation system with tuned inerter damper

Damping performance and optimal design of mid-story isolation system with tuned inerter damper

Design of active vibration isolation system for satellite optical load based on Stewart platform

According to the requirements of hyperstatic environment of a satellite optical load during in orbit operation, the Stewart active vibration isolation platform was designed, and its dynamic equation was established by Newton Euler method. The virtual prototype model was established in ADAMS, and the accuracy of the model was verified by comparing the numerical solution and simulation solution of the modal frequency of the platform; On this basis, the dynamic model is decoupled into six SISO systems, and the optimal controller is designed for each subsystem. Finally, the whole system is simulated by ADAMS/MATLAB, and the displacement response curves of the load before and after control are obtained. The simulation results show that the Stewart active vibration isolation platform can effectively suppress the vibration.

Synchronization characteristics of two induction motors on a floating raft system

The synchronization characteristics of two exciters driven by induction motors independently on a typical double-layer vibration isolation system, that is, the floating raft system are studied in the paper to enhance its vibration attenuation effect. Firstly, a new dynamical model for a floating raft system driven by two exciters is established by the Lagrange equation under considering the coupling effect among floating raft system and exciters. Then, the vibration responses in all directions are obtained by the Laplace transform. Secondly, the synchronization and stability solution are obtained by using the average small parameter method. Thirdly, the results of the theoretical analysis are verified by simulations. Finally, the parameter scope of a floating raft system to enhance its vibration attenuation effect is given. Moreover, compared with the traditional model, the proposed model considering the coupling effect among floating raft system and exciters is more feasible. Additionally, the effects of the mass ratio of the eccentric block, the symmetrical installation distance, parameter differences of two motors, and other dynamic parameters such as system mass and stiffness on their synchronization and the system vibration are discussed. This paper can provide a theoretical reference for the design, modeling, and application of such double-layer vibration isolation systems including the floating raft systems to enhance its vibration attenuation effect.

Optimum design of HNBR and PCR-based isolation system to protect a sensitive article stored in a naval vessel container subjected to shock load

In naval engineering, protecting sensitive articles from shock loads is a major concern, as it may lead to adverse consequences. This paper focuses on the design of a novel Hydrogenated Nitrile Butadiene Rubber (HNBR) and Polychloroprene Rubber (PCR)-based shock isolation system to protect a sensitive article stored in a hollow cylindrical naval vessel container (NVC). Firstly, NVC is modeled as a two-degree-of-freedom lumped parameter model (LPM), wherein isolators made of HNBR and PCR materials are modeled with 5-order polynomial nonlinear stiffness and linear damping. The optimal values of the isolator parameters are obtained using a multi-objective genetic algorithm, and corresponding responses to a shock load are found using MATLAB. Furthermore, a three-dimensional (3D) finite element model (FEM) of the NVC is generated in ABAQUS and subjected to shock loading in a transverse direction to conduct a comprehensive dynamic analysis of the isolation system. In 3D simulation, HNBR and PCR materials are modeled using a hyper-viscoelastic model developed based on experimental test data. The 3D simulation results of the NVC for the optimized design of HNBR and PCR isolators agree with the optimized results of the LPM. Moreover, the proposed HNBR and PCR isolators are very effective in shock reduction.

Design and Experimental Study of a Hybrid Micro-Vibration Isolation System Based on a Strain Sensor for High-Precision Space Payloads.

Micro-vibrations significantly influence the imaging quality and pointing accuracy of high-precision space-borne payloads. To mitigate this issue, vibration isolation technology must be employed to reduce the transmission of micro-vibrations to payloads. In this paper, a novel active-passive hybrid isolation (APHI) system based on a strain sensor is proposed for high-precision space payloads, and corresponding theoretical and experimental studies are implemented. First, a theoretical analysis model of the APHI system is established using a two-degrees-of-freedom system, and an integral control method based on strain sensing is presented. Then, an electromagnetic damper, active piezoelectric actuator, and strain sensor are designed and manufactured. Finally, an APHI experimental system is implemented to validate the effectiveness of electromagnetic damping and strain-sensing active control. Additionally, the control effects of acceleration, displacement, and strain sensors are compared. The results demonstrate that strain sensors can achieve effective active damping control, and the control method based on strain sensors can effectively suppress the payload response while maintaining stability. Both displacement and strain sensors exhibit superior suppression effects compared with the acceleration sensor, with the strain sensor showing greater potential for practical engineering applications than the displacement sensor.

Investigation on the free vibration characteristics of vertical quasi-zero stiffness isolation system considering the disc spring's loading position

This study investigates a quasi-zero stiffness (QZS) isolation system designed for vertical vibration control in isolation structures. The QZS characteristics are achieved by connecting a negative stiffness disc spring in parallel with the linear positive stiffness spiral spring. Initially, the force-displacement relationship of the disc spring is established, taking into account the loading position, and validated through static experiments. Subsequently, the free vibration equations of the QZS system are derived. The Jacobi elliptic functions and the Newton-harmonic balance (NHB) method are then employed to study its free vibration characteristics without considering damping. The results demonstrate that the natural vibration period of the QZS system is related to the nondimensional amplitude and the height of the loaded inner cone. Furthermore, the second-order analytical approximate solution obtained via the NHB method exhibits remarkable accuracy. Finally, the critical damping ratio of the damped QZS isolation system is investigated using a numerical approach. The findings indicate that the critical damping ratio is only correlated with the nondimensional amplitude. This study addresses the gaps in existing research and provide recommendations for the parametric design of vertical QZS isolation system.

Flower Pollination Algorithm for Optimum Design of Base Isolation Systems under Near-Fault Effect

Flower Pollination Algorithm for Optimum Design of Base Isolation Systems under Near-Fault Effect

Optimization design of a two-stage multidirectional vibration isolation system for large airborne equipment

Purpose Improvement and optimization design of a two-stage vibration isolation system proposed in this paper are conducted to ensure the device of electronic work effective.Design/methodology/approach The proposed two-stage vibration isolation system of airborne equipment is optimized and parameterized based on multi-objective genetic algorithm.Findings The results show that compared with initial two-stage vibration isolation system, the angular vibration of the two-stage vibration isolation system becomes 3.55 × 10-4 rad, which decreases by 89%. The linear isolation effect is improved by at least 67.7%.Originality/value The optimized two-stage vibration isolation system effectively improves the vibration reduction effect, the resonance peak is obviously improved and the reliability of the mounting bracket and the shock absorber is highly improved, which provides an analysis method for two-stage airborne equipment isolation design under complex dynamic environment.

Mechatronic design of a composite vibration isolation system

Composite materials have attracted researchers in vibration and noise control applications due to their significant dynamic characteristics such as high strength and high damping level. In this paper, a Glass Fiber Reinforced Composite material (GFRC) is presented as a vibration isolation system to control vibration levels in industry. In addition, the impact of integration of a mechatronic control system to improve the machining process and increase the control of vibration nature. A prototype of an industrial cam–follower machine is motorized, and the Frequency Response Function (FRF) is recorded using a B&K data acquisition analyzer at five rotational speeds. The transmitted vibrations to the machine foundation are estimated without any isolation system. Then, two optimized GFRC plates of optimum stacking sequences are used as an isolation system to reduce the transmitted vibration. The displacement transmissibility is calculated theoretically and experimentally. The results show that the use of GFRC plates as an isolator reduces the vibration level of the system by 98.46% and 98.5% for [90/90/90/0/0]s and [90/ ± 45/ ± 35/90/ ± 35]s GFRC configurations respectively.

Solution of the Problem of Parameters Identification for Vibration Damping Materials

Statement of the problem. For the design of vibration isolation systems of buildings, structures and hardware, it is necessary to have information on the dynamic characteristics of vibration damping materials. These parameters are recommended to be determined on the basis of tests as per GOST 16297-80 or GOST R ISO 10846-1-2010. At the `same time, these methods are limited by the model used in them – a single-mass oscillatory model of the Kelvin-Voigt type and cannot fully assess both the dynamic and rheolo-gical characteristics of materials. Results. The use of a variety of dynamic models of materials allows one to improve the accuracy of describing their properties and predict the behavior of vibration isolation systems over time. Conclusion. The algorithm presented in the article for identifying the parameters of vibration damping materials models allows one to use various models and more accurately describe the properties of materials.

Quasi-zero stiffness interval optimization design and dynamics analysis of a new bi-directional horizontal isolation system

The quasi-Zero Stiffness (QZS) isolation system is a typical nonlinear isolation system, which has high static stiffness characteristics to improve the bearing capacity and deformation resistance, and its low dynamic stiffness characteristics can reduce the inherent frequency of the system to realize a wider vibration isolation frequency band, so it has a more excellent low-frequency vibration isolation performance compared with the linear system. In this paper, a horizontal QZS isolator is constructed based on a pre-compressed oblique spring system, and two sets of the horizontal QZS isolators are mechanically assembled to work together to achieve a bi-directional horizontal QZS isolation system. Considering that the construction of two sets of horizontal vibration isolators is approximately the same, we focus on one of the isolators for the static analysis and derive the parameter conditions to be satisfied for achieving quasi-zero stiffness characteristics. We considered the effect of each adjustable parameter of the horizontal vibration isolator on the mechanical performance of the QZS system, and sought to optimize the QZS interval to improve the vibration isolation performance. A comparative study of the dynamical properties between the QZS system with ordinary and optimized parameters, as well as the equivalent linear system, is further carried out by means of nonlinear approximate analysis. Finally, the dynamic characteristics of the bi-directional horizontal QZS system and the equivalent linear system are compared by shaker tests on the prototype device, which proved the excellent vibration isolation performance of the proposed QZS isolation system.

An overview of the development of intelligent materials and active vibration isolation systems for vehicles

Intend to reduce the impact of external vibrations on the smoothness of automotive precision instruments and vehicles and to improve the operational accuracy of automotive precision instruments and the comfort of passenger vehicles, vibration isolation technologies are used and active control systems are applied to vibration isolation systems. The extensive use of smart materials in vibration isolation systems has enabled the design of vehicle structures based on smart materials to meet the suppression of vehicle vibrations well. This paper reviews the application of commonly used smart materials to the field of vehicle vibration damping, summarizes the configuration design of single-axis and multi-axis vibration isolation systems, and develops the thinking behind the application of active control technology to other carriers, pointing out the future research direction of current smart materials for vehicles.

Experimental Study on the Active Control and Dynamic Characteristics of Electromagnetic Active–Passive Hybrid Vibration Isolation System

Targeting the problems of conventional active–passive hybrid vibration isolation systems, such as low output force, poor bearing capacity, large power loss and inability to withstand strong impacts, this paper proposes an active–passive hybrid vibration isolation system combining an electromagnetic actuator, rubber passive vibration isolator and magnetorheological damper. The overall design of the hybrid vibration isolation system is first introduced. Then, a two-dimensional electromagnetic frequency-domain simulation is carried out on the electromagnetic actuator to obtain the output characteristics. A three-dimensional modeling is conducted to simulate the electromagnetic–mechanical coupling in the time–frequency domain to obtain nephograms of the magnetic flux diffusion distribution and power loss. Then, a dynamic stiffness test is carried out on the rubber vibration isolator to obtain the dynamic stiffness characteristics and the damping angle curve. At the same time, an adaptive suppression filtered-x least mean square (ASFXLMS) algorithm is proposed to adjust the update of the control weight coefficients to ensure that the current signal does not exceed the effective operating range of the actuator when the electromagnetic actuator is subjected to strong external disturbances. Finally, a hybrid vibration isolation system-based active vibration isolation experimental platform is built, and multifrequency line spectra active–passive vibration isolation experiments are carried out. The results demonstrate that the hybrid vibration isolation system has good control effects in the time–frequency domain and shows good robustness when subjected to impact.

Seismic resilient design and negative stiffness-assisted nonlinear isolation system for adjacent non-coaxial buildings linked by corridors

Adjacent non-coaxial buildings have been widely built owing to complementary functions, while the non-coaxial layout could cause a great torsion effect and seismic-induced damage. This study proposes a negative stiffness-assisted hybrid isolation system and a corresponding earthquake-resilient design methodology to upgrade the multi-performances of the adjacent non-coaxial buildings and linking corridors. The hybrid isolation system includes synthetic employment of various isolators and negative-stiffness amplification systems comprised of nonlinear viscous dampers for adjacent structures, as well as tailored friction bearing for linking corridors. The mechanical property and model of the adjacent non-coaxial buildings are established, based on which a typical case is introduced. Next, the conception of the earthquake-resilient design method and procedure is elaborated, following which the functionality of each component in the hybrid system is investigated. The advantages of the developed hybrid isolation system and design methodology are illustrated by a systematic parametric analysis and time history analysis for the typical case. The results show that the torsional effect can be a dominant problem in non-coaxial adjacent buildings, which can be solved by the flexibly tailored negative stiffness effect produced by the negative stiffness-assisted isolation system. The collaboration within the proposed hybrid isolation system can produce improved isolating and enhanced nonlinear energy dissipation effects on adjacent buildings, simultaneously limiting the isolation displacement without weakening the isolating effect. The optimized friction sliding bearings effectively reduce the relative torsion concentrated on the linking corridors with a maintained function. The hybrid isolation system and earthquake-resilient design can be adopted as a high-efficiency solution to the non-coaxial linked historic buildings with insufficient seismic resistance.

A Fully Integrated 0.6 Gbps Data Communication System for Inductive-Based Digital Isolator with 0.8 ns Propagation Delay and 10−15 BER

Digital isolators are implemented to protect low-voltage electronics and ensure human safety during high-voltage surge events. In this work, we present the design of an inductive-based digital isolation system that can sustain up to 1 kVrms breakdown voltage. The proposed system is designed using the pulse polarity modulation scheme and fabricated in a 0.35 μm CMOS. Two identical dies are bounded within the IC package, with one die housing the transmitter (Tx) and the isolation transformer, while the other die contains the receiver (Rx). Two different customized designs between three metal layers are implemented to form the isolation element. The transformer’s secondary coil is constructed in metal-1, while the primary coil is formed in metal-2 and metal-3 for comparing the system functionality, isolation capability, and propagation delay. The functionality has been verified by measurements for an operating frequency of 300 MHz with a 2.6 ns propagation delay and an energy consumption of 8.15 × 103 pJ/bit at 1 Mbps. The chip was tested under extreme temperatures and achieved a maximum measured common mode transient immunity (CMTI) of 500 V/μs. Jitter has been examined to ensure fast transmission at a bit error rate (BER) of 10−15 with a total jitter (TJ) of 188.18 ps.

Passive Isolator Design and Vibration Damping of EO/IR Gimbal Used in UAVs

One of the most critical factors affecting the quality of the images captured by the surveillance systems used in the unmanned aerial vehicles is the vibrations transmitted from the aircraft to the gimbal. The gimbal used in unmanned aerial vehicles is essential equipment, holding the camera steadily and accurately and pointing it in the desired direction. Within the scope of this article, a passive vibration isolation system design has been made for the two-axis electro-optical gimbal used in the mini unmanned aerial vehicle. By choosing the spring-damper system among different methods, the design that isolates the harmonic vibration from the platform on a single axis has been made using the analytical method. The analytical method was used to create a design that isolates the harmonic vibration from the platform along a single axis. In addition, the part named 'Pan Yoke', which contains this damper system, was designed with a computer-aided design program, and natural frequency values were checked with Ansys modal analysis. The frequency of the vibration transmitted from the air vehicle to the gimbal and the natural frequency of the designed part have been determined to be close to each other, at around 200 Hz. The natural frequency values of this part were optimised with various design changes and topology optimisations to prevent the part from resonating.