Vibration Reduction Technology Research Articles

Research status and dynamic analysis of damping and vibration reduction technology of rotating machinery rotor system

Research status and dynamic analysis of damping and vibration reduction technology of rotating machinery rotor system

Control Mechanism and Noise Reduction Effect of CVDM on Rail Transit Steel Bridge: Experimental and Numerical Study

Steel bridge, as one of the main structural types in bridge design, has been widely used in rail transit. However, the train-induced vibro-acoustic problem of the bridge has become increasingly prominent. The vibration and noise characteristics must be more significant and complex than steel truss bridge because of too many components. Viscoelastic damping materials (VDMs) have the characteristics of both viscous liquid and elastic solid, and have better damping performance than other damping materials. Therefore, VDM plays an important role in vibration and noise reduction technology. In applications, VDM is usually combined with constraining materials to form composite viscoelastic damping materials (CVDM). In this paper, based on the dynamic receptance method and superposition principle, the coupling model of vehicle–track–bridge in the frequency domain is first established, and then the vibration and noise prediction model of a steel truss bridge with CVDM is established based on RUK theory and statistical energy analysis (SEA) method. Based on the prediction model, the natural dynamic characteristics of typical components of steel truss bridges with CVDM were investigated, and the control mechanism and influence rule of CVDM on train-induced vibration and noise of steel bridges were revealed.

Innovative Applications of Intelligent Technology in Infant Care Products: A Study on the Design of Bottle Warmers and Milk Warmers

This paper delves into the innovative application of intelligent technology in the design of infant care products, with a particular focus on the design of smart bottle warmers and milk warmers, and their impact on user experience. The study begins by analyzing the current market demands and limitations of existing products in the field of infant care products, followed by a detailed discussion of the design features, technological advantages, and user experience of HAUTURE brand products. Through an in-depth analysis of the temperature control technology of the smart bottle warmer, the user interface design, and the dual-sealing system and vibration reduction and noise reduction technology of the milk warmer, this paper reveals how intelligent technology enhances product performance and user satisfaction. In addition, this paper examines the role of user feedback in product design improvement and proposes solutions to technical challenges. Finally, it provides an outlook on the future development trends of intelligent infant care products, predicting how intelligent technology will further shape innovation in this field.

Research on Active Vibration Reduction Technology for Actively Supporting Main Mirror of Space Telescope

Research on Active Vibration Reduction Technology for Actively Supporting Main Mirror of Space Telescope

Vibration reduction technology using modal energy propagation analysis method

Since the noise generated by mechanical structures affects the merchantability, it is important to predict the noise and vibratory characteristics at the first design stage. The frames and panels or trim parts in automobiles are coupled systems of the rigid and flexible substructure. In these systems, vibration of the flexible structures often becomes one of the major noise sources when the excitation force is applied to the rigid structure. FEM and modal analysis technique are not sufficient to carry out the effective low noise design in higher frequency because of high modal density and complexity of mode shape. Modal energy propagation method, proposed in this paper, is based on the mode synthesis method and the vibration power flow between the eigen modes of the rigid and flexible structures. Previous studies have verified that the vibration level can be reduced by extracting modes that contribute highly to the vibration power flow between subsystems and changing their characteristics. In this report, we present the results of applying this method to a coupled system of a body and panel structures in automobiles and verifying its validity. The structural modifications obtained from this analysis method were verified for their effectiveness in decreasing vibration.

Integrated transmission vibration reduction technology based on the “isolating-reducing-optimizing” method

Hydro-mechanical transmission devices that can transfer power from the engine to the action mechanism are widely used in heavy-duty vehicles. It has many components, and the operating conditions are complex and changeable. Multi-source excitations and load disturbances easily aggravate vehicle vibrations, which has an adverse impression on the running quality of the whole vehicle. Therefore, it is necessary to carry out research on the vibration problems caused by multiple excitation sources. Thus, in this paper, a new vibration reduction method of “isolating-reducing-optimizing” for hydro-mechanical transmission devices is proposed to optimize such devices in multiple dimensions to improve their dynamic responses. This novel method optimized the coupling stiffness to isolate the vibration caused by the engine fluctuating torque. Moreover, the vibration energy decoupling method and optimization method are used to decouple the rigid body vibration of the mounting system, and gear profile modification method based on a dynamic model is used to attenuate the internal high frequency vibration caused by the gear meshing excitation. Finally, the steady-state conditions and cycle conditions vibration tests of the transmission system before and after optimization are carried out. The time and frequency domain vibration responses of the transmission system before and after optimization are compared to verify the effectiveness of the optimization method.

Study on the Mechanism and Prevention of Frequent Mine Seismic Events in Goaf Mining under a Multi-Layer Thick Hard Roof: A Case Study

Mine seismic events are an inevitable dynamic phenomenon occurring in deep mines. A scientific and rational method is needed to evaluate and understand mine seismicity and its induced disasters. In the Ordos mining area of North China, multiple groups of thick hard-bedded sandstone formations commonly exist in the overlying strata of Jurassic coal seams. In recent years, frequent mine seismic events in many large mines of Ordos have resulted in suspended or limited production, which seriously threatens the safe and efficient operation of 10-million-ton modern mines in China. Therefore, taking the frequent occurrence of mine seismic events in the mining process of goaf working face with a multi-layer thick hard roof in Ordos mine as the research background, this study investigated the mechanism and prevention of mine seismic in goaf working face with the methods of case study, theoretical analysis and field monitoring. The following conclusions are made: when the goaf working face is mined, an “advanced and lateral” L-form roof forms under the coupled influence of the lateral suspension plate formed above the upper working face and the roof of the working face. Due to the common influence from “advanced and lateral” L-form roof activation, the gradually breaking multi-layer thick hard roof, thick hard roof group bending and prying effects, in addition to excessively fast or uneven mining speed, mine seismic events will occur frequently when the exceedance warning index (EWI) is breeched. On this basis, coordinated blasting to break the roof along two roadways and within the working face is put forward as a measure with the purpose of preventing and controlling mine seismic events, and a robust effect on mine seismic reduction and disaster prevention is obtained in field application. The research results can serve as a reference for the development and application of mine seismic mechanism and blasting vibration reduction technology on the working face where there is a multi-layer thick hard roof, thereby supporting a strategy of promoting the resource development and energy security of deep mines.

Investigation on low-frequency sound propagation characteristics of fluid-filled steel pipeline

With the development of vibration reduction and noise reduction technology, the propeller noise, hydrodynamic noise and equipment base noise in submarines have been effectively suppressed. The sea pipeline system contains mechanical noise and fluid pulsation noise, which is one of the main noise sources of submarines. The fluid-filled steel pipeline is the basic component of the sea pipeline system. It is of great significance to study the low-frequency sound propagation characteristics of the fluid-filled steel pipeline system to effectively suppress the low-frequency noise of the pipeline system to the sea and achieve quiet submarines. At present, there are few studies on the sound propagation of fluid-filled steel pipeline, and most of them refer to gas-filled pipes. It is believed that there are low-frequency plane waves in the pipeline, which leads to the design of muffling devices only for liquids, the role of the pipe wall in the propagation of low-frequency sound is ignored. In this paper, according to the relationship between normal waves and medium wave velocity, a sound propagation model of fluid-filled steel pipeline is proposed, which is verified by experimental research. Through this model, the propagation path of low-frequency sound in the fluid-filled steel pipeline is clarified, which has an important guiding role in the vibration and noise reduction of the fluid-filled pipeline system.

Vibration reduction technology and the mechanisms of surrounding rock damage from blasting in neighborhood tunnels with small clearance

Interlaid rock is an important component in the construction of neighborhood tunnels that supports and reinforces the area between two tunnels. However, the blasting load during excavation can sometimes damage the interlaid rock and threaten the stability of a tunnel’s structure. This paper presents a case study of the small clearance section of the Liantang highway tunnel project in Shenzhen, China, where the minimum distance between the two tunnels involved is only 0.5 m. To reduce the damage to the interlaid rock caused by blasting loads, we proposed a four-part excavation method with a vibration-cushioning rock layer in the following tunnel of neighborhood tunnels. Numerical simulation was used to model the damage prevention mechanism of the vibration-cushioning rock layer and to better understand the propagation of cracks in the interlaid rock. Furthermore, based on the simulation results, combined microseismic controlled-blasting technology was implemented, using innovative blasting patterns combined with different charge structures and blasting equipment designed according to the varying thickness of the interlaid rock. Finally, this implementation succeeded in protecting interlaid rock during blasting operations.

Study on Band Gap Characteristics of Phononic Crystal Double-Layer Beam Structure Attached by Multilayer Cylinder

Intended for the vibration and noise control problems faced by many engineering fields, a fresh variety of phononic crystal beam structure was constructed by attaching a one-dimensional periodic multilayer cylinder to a double-layer beam structure. Utilizing the finite element method and the Bloch theorem, the vibration modes of the band structure, the critical point of the band gap and the associated finite structure’s vibration transmission is estimated, and then the band gap characteristics of the structure are comprehensively studied. The results show that reasonable parameter design can achieve vibration and noise control in a certain frequency range. Based on the modal analysis, the mechanism of band gap opening is revealed. By comparing the single-layer beam and double-layer beam with the same parameters, the advantages of the double-layer beam in vibration reduction and noise reduction are shown. The study’s findings offer a fresh concept for ship engineering disciplines including vibration and noise reduction technology.

Computer-Aided Analysis of Small Clear Space Intersection Tunnel and Heavy Load Railway Surrounding Rock Structure Dynamic Response Characteristics Analysis under Intelligent Manufacturing

Among many tunnel construction projects, small clear tunnels have been the focus of urban rail transit construction in recent years. The purpose of this research work is to study the dynamic response characteristics of the surrounding rock structure of a heavy-duty railway with a small clearance crossing tunnel. It is proposed to analyze the dynamic response characteristics of the surrounding rock structure through the frequency response function. The vertical acceleration, tensile force, stress, and internal strength of the pipe section are specifically analyzed. The influence of the pipe joint and the assembly method on the dynamic response is also analyzed. The influencing factors of stability are analyzed from buried depth, clear distance, and surrounding rock grade. Studies have shown that the minimum clear distance of crossing tunnels increases nonlinearly with the increase of tunnel depth and gravity, and decreases nonlinearly with the increase of cohesion, internal friction angle, calculated internal friction angle, and lateral pressure coefficient. When other parameters are the same and when the side pressure coefficient is less than 1, the minimum clear distance is larger than that of the side pressure coefficient when it is equal to 1. When the vibration frequency exceeds 100 Hz, the coherence coefficient is basically close to 1, indicating that the frequency response function response result of this section is the most reliable. It is hoped that it can provide a reference for the dynamic stability analysis of the surrounding rock structure of the heavy-duty railway surrounding rock structure and the surrounding stratum and the research of structural vibration reduction technology for the small clearance crossing tunnel in the future.

Analysis and Application of Vibration Damping Hole in Tunnel Working Face Based on Grey Correlation Analysis

In the process of tunnel blasting construction, certain vibration hazards will be caused to adjacent buildings. Therefore, it is necessary to explore feasible vibration reduction measures in the construction process. Combined with field measurement and numerical calculation, the law of vibration reduction effect of vibration reduction holes in the blasting construction of subway tunnels is analyzed. The gray correlation theory is used to determine the influence degree of vibration reduction hole parameters on the vibration reduction effect; each parameter is clarified, and the primary and secondary relationship of each parameter in the vibration reduction effect is clarified. Among them, the effect of damping hole spacing is particularly obvious. Combined with numerical calculation and comprehensive analysis of on-site construction effects, it is found that during the construction process, the distance between the vibration damping holes is 120 mm, the distance between the vibration damping holes and the explosion source is 2000 mm, the diameter of the vibration damping holes is more than 120 mm, the depth of the vibration damping holes is 1200–1500 mm, and double-row vibration-damping hole spacing is 50–100 mm, which can achieve a better vibration-damping effect. The research results will provide a reference vibration reduction technology for the blasting construction of urban shallow tunnels and have certain reference value and guiding significance for the blasting scheme design and vibration control of similar projects.

Fabrication and vibration isolation capacity of multilayer gradient metallic lattice sandwich panels

Sandwich structures have been widely used in ship, aerospace, vehicle and other fields, due to their lightweight and high load bearing properties. With the rapid development of ship stealth technology, multifunctional structures with lightweight, high loading capacity and excellent vibration reduction performances are urgently needed. To achieve the above multifunctional characteristics, we design and fabricate novel gradient metallic lattice sandwich structures via cutting and snap-fit approach. The gradient is governed by the size of the truss width. Modal test and shaking table sweep frequency test are conducted to characterize the vibration characteristics and vibration isolation performances of the structures. The frequency responses are simulated by modal superposition method, which is verified by experimental results. Furthermore, the influences of interlayer gradient, face sheet thickness and hybrid materials on the vibration performances are explored. Results show that the interlayer gradient and face sheet thickness have significant effects on the vibration characteristics of the present structures. The positive gradient structure has the best vibration isolation performance among all the gradient structures. What’s more, reducing the thickness of the face sheets and using hybrid materials are beneficial to achieve low-frequency vibration isolation effect, which can provide a reference for ship vibration and noise reduction technology.

Powertrain shuffle-mode resonance suppression by means of flywheel mounted torsichrone centrifugal pendulum vibration absorbers

A flywheel mounted centrifugal pendulum absorber (CPVA) is designed to completely suppress the low frequency shuffle-mode resonance of a heavy-duty truck powertrain by exploiting the eigenfrequency veering property of the CPVA. The shuffle-mode is excited by the half-order torque of a five-cylinder engine in a downspeeded powertrain during cruising conditions. It is shown that the design of the CPVA may be performed by linear analysis of the CPVA and powertrain system. The linear design is then validated by full nonlinear simulations of the powertrain. A complete suppression of the shuffle-mode resonance is achieved with relatively small total mass of the pendula which makes it highly possible to implement in practice. Downspeeding and downsizing of combustion engines, without sacrificing the power output, are methods to reduce emissions, although, resulting in increased noise and vibration using conventional vibration reduction technology. The CPVA is an order tuned device that can help to reduce the increased vibrations and thus help to reduce the environmental impact of heavy-duty vehicles.

Research on Structural Vibration Reduction Technology of Rotating Machinery Based on Dynamic Vibration Absorption

Rotating machinery such as steam turbines, generators, and fans are generally composed of rotating parts and stator parts. The structural vibration that occurs on the stator parts often seriously affects the safe and stable operation of the equipment. Usually, a part of the structural vibration failure can be solved by dynamic balancing. However, due to the complexity of the system, another part of the structural vibration failure cannot be completely solved by dynamic balancing. For solving structural vibration faults, a vibration reduction technology based on the dynamic vibration absorption is proposed. This method designs a dynamic vibration absorber so that its natural frequency is equal to the excitation force frequency. The vibration of the stator is transferred to the absorber, so as to achieve the purpose of vibration reduction. Then, a rotor system test bench was built, and the vibration absorption device parameters were designed according to the vibration data of the test bench. Through experiments, it is proved that this method has a good vibration reduction effect.

Research on vibration isolation and noise reduction technology for the metro depot

Under the situation of increasingly tight land resources, the development of depot superstructures has been applied in many cities.The noise generated by the passage of subway vehicles and the vibration of buildings are problems that need to be solved urgently. The use of vibration and noise reduction measures for the track is an important solution.In order to study the vibration reduction effect of the depot vibration reduction measures, taking the Guangzhou Metro Chentougang Depot as an example, the vibration and noise reduction technology of the depot is studied.The research results show that: (1) It can be seen from Table 1 and Table 2 that after the vehicle speed is corrected to the same speed, the Z vibration level of the trapezoidal sleeper section at the foot of the ballast slope is lower than that of the ordinary transverse sleeper section, and the train speed is 10km/h (low speed). The insertion loss VLZ is 8.24dB, and the insertion loss VLZ is 8.53dB under the train speed of 35km/h (high speed).(2) At the measuring point 7.5m away from the centerline of the track, the Z vibration level of the trapezoidal sleeper section is smaller than that of the ordinary transverse sleeper. The insertion loss VLZ under low-speed conditions is 8.60dB, and the insertion loss VLZ under high-speed conditions is 8.93dB.

Vibration reduction technology of airborne photoelectric stabilized sighting platform

Vibration reduction technology of airborne photoelectric stabilized sighting platform

Experimental Study on Vibration Reduction Technology of Hole-by-Hole Presplitting Blasting

In order to effectively reduce the disturbance of the precrack blasting vibration on slope rock mass, except paying attention to the damping effect of the precrack, it is also necessary to optimize the blasting parameters and initiation mode of the precrack itself. Based on the blasting theory and empirical formula, the parameters of presplitting blasting such as the hole diameter, hole spacing, charge decoupling coefficient, and line charge density were determined, and field tests of conventional pre-splitting blasting and presplitting blasting with precise delay and hole-by-hole initiation were carried out on the west slope of Buzhaoba. Regression analysis was carried out on the vibration monitoring data, and the blasting vibration attenuation regularity of slope particles was obtained. By comparing the monitored vibration velocity of the two presplitting blasting tests and the forecast results of theoretical calculation, the average reduction rate of the conventional same row blasting vibration is 26.40%, while that of the hole-by-hole blasting vibration can reach 41.45% with a half hole rate of 80.7% and an irregularity of about 130 mm. Results show that the effect of precise delay initiation between preholes based on the digital electronic detonator is better than that of the simultaneous initiation of preholes. Therefore, it is suggested that the hole-by-hole presplitting blasting technology should be applied in the excavation of boundary slope and the treatment of high and steep slope.

Vibration characteristics of pressure pipelines at pumping stations and optimized design for vibration attenuation

Abstract To explore the effects of different pressure pipeline layouts on pumping station pipeline vibration, this study establishes an ALGOR numerical model for pipeline flow considering fluid–structure interactions. A data acquisition and signal processing vibration test system is used to obtain vibration signals and verify simulation results including pipeline fluid velocity, fluid pressure, and transient stress. Based on the flow's vibration excitation characteristics, we consider structural vibration reduction technology and propose an optimized design scheme. As an example, we apply this approach to a pressure pipeline at the Ningxia Yanhuanding Pumping Station Project. Results show strong vibrations at the water inlet, the junction between the branch and main pipes, and the water outlet, with even stronger vibration at the inlet than at the outlet. In the optimized design scheme, adjusting the distance between the branch pipes only weakly reduces flow-generated pipeline vibration; increasing the pipe diameter and changing the main pipe's relative orientation show stronger effects. Vibration reduction is optimized for a main pipe dip angle of 2–5° relative to the branch pipes, simultaneously decreasing pumping station energy loss. These results provide a theoretical and practical basis for optimal design of pressure pipelines at high-lift pumping stations.

Research on damping addition and vibration reduction technology of frame aerospace electronic chassis

This paper poses a box instrumentation in aerospace electronic chassis TO-5 encapsulation relay under the action of impact environmental load state of reverse fault mode, by reasonable single frames of viscoelastic damping materials added, increasing box style structure between the PCB mechanical installation interface damping ratio and frequency ratio, finally realizes the transfer rate is reduced, achieve instrumentation relay PCB, lower impact acceleration response. By adding damping cushion to the frame machine installation interface, the load transfer path of impact mechanics is optimized to reduce the installation stiffness and change the fundamental frequency characteristics of the whole machine.