Pub Date : 2020-09-30DOI: 10.20855/ijav.2020.25.31674
M. Khiavi, M. Ghorbani, A. Rahmati
One of the major factors in an economic project of new concrete dams and safety valuation of available dams in seismic areas is the control and dissipation of the induced hydrodynamic pressure induced by dam and reservoir interaction. As one of the main control functions, dissipating the induced hydrodynamic pressure on the upstream face of the dam is considered in the evaluations. In this paper, the effects of a rubber damper as an isolation layer on the dam’s seismic control have been investigated. For optimization of the rubber damper thickness and height, the Monte Carlo probabilistic analysis is used. The ANSYS program on the basis of finite element technique is applied for modeling and analysis. The Pine Flat dam in California, due to components of El Centro, San Fernando and North Ridge earthquake is modeled as a case study to evaluate the effect of upstream isolation layer on seismic control and optimization. The effect of the thickness and height of the rubber damper on reducing the responses is investigated and the optimum thickness and height are selected using sensitivity analysis for safe and economic design. The obtained results show the capability of the rubber damper in the seismic and hydrodynamic control of the sample model.
{"title":"Seismic Optimization of Concrete Gravity Dams Using a Rubber Damper","authors":"M. Khiavi, M. Ghorbani, A. Rahmati","doi":"10.20855/ijav.2020.25.31674","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.31674","url":null,"abstract":"One of the major factors in an economic project of new concrete dams and safety valuation of available dams in seismic areas is the control and dissipation of the induced hydrodynamic pressure induced by dam and reservoir interaction. As one of the main control functions, dissipating the induced hydrodynamic pressure on the upstream face of the dam is considered in the evaluations. In this paper, the effects of a rubber damper as an isolation layer on the dam’s seismic control have been investigated. For optimization of the rubber damper thickness and height, the Monte Carlo probabilistic analysis is used. The ANSYS program on the basis of finite element technique is applied for modeling and analysis. The Pine Flat dam in California, due to components of El Centro, San Fernando and North Ridge earthquake is modeled as a case study to evaluate the effect of upstream isolation layer on seismic control and optimization. The effect of the thickness and height of the rubber damper on reducing the responses is investigated and the optimum thickness and height are selected using sensitivity analysis for safe and economic design. The obtained results show the capability of the rubber damper in the seismic and hydrodynamic control of the sample model.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"425-435"},"PeriodicalIF":1.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45975092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-30DOI: 10.20855/ijav.2020.25.31632
F. Unker
A special combined gyro-pendulum stabilizer (a gyroscope with coupling to a pendulum) mounted on a vibrating mass is considered for investigation of the vibration responses. This paper mainly focuses on the derivation of the frequency equations and on finding the required angular momentum for vibration control of the system. Besides, there is also an ANSYS simulation model of gyro-pendulum, which was built to verify the mathematical model. The dynamic responses of both that obtained from ANSYS simulation and that obtained from numerical solving of a Lagrangian mathematical model are analyzed comparatively. The angular momentum (ΩIp), in relation to the natural frequency (ωn) of the primary mass, shows that this vibration control device is more adaptable than other conventional ones by producing unidirectional thrust along the forcing excitation axis whilst the gyroscope is spinning.
{"title":"Tuned Gyro-Pendulum Stabilizer for Control of Vibrations in Structures","authors":"F. Unker","doi":"10.20855/ijav.2020.25.31632","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.31632","url":null,"abstract":"A special combined gyro-pendulum stabilizer (a gyroscope with coupling to a pendulum) mounted on a vibrating mass is considered for investigation of the vibration responses. This paper mainly focuses on the derivation of the frequency equations and on finding the required angular momentum for vibration control of the system. Besides, there is also an ANSYS simulation model of gyro-pendulum, which was built to verify the mathematical model. The dynamic responses of both that obtained from ANSYS simulation and that obtained from numerical solving of a Lagrangian mathematical model are analyzed comparatively. The angular momentum (ΩIp), in relation to the natural frequency (ωn) of the primary mass, shows that this vibration control device is more adaptable than other conventional ones by producing unidirectional thrust along the forcing excitation axis whilst the gyroscope is spinning.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"355-362"},"PeriodicalIF":1.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44182303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-30DOI: 10.20855/ijav.2020.25.31609
T. Dovedi, R. Upadhyay
The rolling element bearing is one of the most significant components of any rotating machinery. However, the foremost cause of malfunction in any rotating machine is due to defects like cracks, dents, spall, pits, etc. in ball bearings. Early diagnosis of these bearing faults is highly essential to avoid an accidental shutdown of rotating machinery. In the present work, a novel technique of bearing fault diagnosis is proposed following double decomposition of the vibration activity. The experimentally recorded vibration signals are processed through two stages of decomposition viz. Empirical Mode Decomposition and Tunable Q-factor Wavelet Transform based Time-Frequency decomposition. Subsequently, sub-bands of decomposed time-frequency activity are acquired and discriminable features are computed. Fractal Dimension (FD) based features are extracted from each decomposed sub-band as complexity measures of time-frequency sub-bands. In order to classify bearing faults, a Support Vector Machine classifier is trained with acquired features and classification performance is evaluated. The results of classification reveal that the proposed double decomposition technique is a potential candidate in extracting viable vibration signatures for fault identification. The study is conducted on Case Western Reserve University bearing datasets.
{"title":"Diagnosis of Ball Bearing Faults Using Double Decomposition Technique","authors":"T. Dovedi, R. Upadhyay","doi":"10.20855/ijav.2020.25.31609","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.31609","url":null,"abstract":"The rolling element bearing is one of the most significant components of any rotating machinery. However, the foremost cause of malfunction in any rotating machine is due to defects like cracks, dents, spall, pits, etc. in ball bearings. Early diagnosis of these bearing faults is highly essential to avoid an accidental shutdown of rotating machinery. In the present work, a novel technique of bearing fault diagnosis is proposed following double decomposition of the vibration activity. The experimentally recorded vibration signals are processed through two stages of decomposition viz. Empirical Mode Decomposition and Tunable Q-factor Wavelet Transform based Time-Frequency decomposition. Subsequently, sub-bands of decomposed time-frequency activity are acquired and discriminable features are computed. Fractal Dimension (FD) based features are extracted from each decomposed sub-band as complexity measures of time-frequency sub-bands. In order to classify bearing faults, a Support Vector Machine classifier is trained with acquired features and classification performance is evaluated. The results of classification reveal that the proposed double decomposition technique is a potential candidate in extracting viable vibration signatures for fault identification. The study is conducted on Case Western Reserve University bearing datasets.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"327-340"},"PeriodicalIF":1.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41529219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three types of piezoelectric micropumps following different configurations: single, series, and parallel connection, are developed and investigated. All the micropumps are fabricated by wet etching technology and sealed by high temperature glass bonding. They share the same dimension characteristic of diffuser/nozzle microchannels. Verifying the impact of adding series or parallel connected pump chambers on single chambers, as well as verifying the performance of the flow rate, pressure and piezoelectric transducer vibration of three micropumps have been examined. Through the comparisons between three kinds of micropumps, the results show that the flow rate of the micropumps with parallel connected pump chambers have a higher flow rate than that of micropumps with single and serial connected pump chambers under the same driving conditions. In addition, both the flow rate and pressure with the serial micropump are the lowest. The pressure of the micropump with single pump chamber is larger than other kinds of micropumps at certain driving frequencies. Consequently, increasing the pump chambers cannot always increase the performance of the micropump. This coincides with the theory analysis. Finally, the vibration performance of piezoelectric transducers with three micropumps have been carried out. The parallel transducer has a higher vibration displacement than the other two kinds of micropumps. These results have great potentials for integration into labs with a chip or microfluidic driven systems.
{"title":"Experimental Investigation of Piezoelectric Micropumps with Single, Series or Parallel Pump Chambers","authors":"Yanfang Guan, Mingyang Bai, Xiangxin Meng, Yansheng Liu, Fengqian Xu","doi":"10.20855/ijav.2020.25.31688","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.31688","url":null,"abstract":"Three types of piezoelectric micropumps following different configurations: single, series, and parallel connection, are developed and investigated. All the micropumps are fabricated by wet etching technology and sealed by high temperature glass bonding. They share the same dimension characteristic of diffuser/nozzle microchannels. Verifying the impact of adding series or parallel connected pump chambers on single chambers, as well as verifying the performance of the flow rate, pressure and piezoelectric transducer vibration of three micropumps have been examined. Through the comparisons between three kinds of micropumps, the results show that the flow rate of the micropumps with parallel connected pump chambers have a higher flow rate than that of micropumps with single and serial connected pump chambers under the same driving conditions. In addition, both the flow rate and pressure with the serial micropump are the lowest. The pressure of the micropump with single pump chamber is larger than other kinds of micropumps at certain driving frequencies. Consequently, increasing the pump chambers cannot always increase the performance of the micropump. This coincides with the theory analysis. Finally, the vibration performance of piezoelectric transducers with three micropumps have been carried out. The parallel transducer has a higher vibration displacement than the other two kinds of micropumps. These results have great potentials for integration into labs with a chip or microfluidic driven systems.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"453-460"},"PeriodicalIF":1.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41531087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-30DOI: 10.20855/ijav.2020.25.31671
Qi Huang, R. Wu, Li-hong Wang, Longtao Xie, Jianke Du, T. Ma, Ji Wang
For the design of quartz crystal resonators, finding and determining the vibration modes have always been very important and cumbersome. Vibration modes are usually identified through plotting displacement patterns of each coupled modes and making comparisons. Over the years, there is not much improvement in the identification procedure while tremendous efforts have been made in refining the equations of the Mindlin plate theory to obtain more accurate results, such as the adoption of the Finite Element Method (FEM) by implementing the high-order Mindlin plate equations for efficient analysis. However, due to the old fashioned mode identification method, the FEM application is still inadequate and cannot be fully automated for this purpose. To have this situation improved, a method using the proportions of strain and kinetic energies to characterize the energy level of each vibration mode is proposed. With solutions of displacements, the energy distribution of each vibration mode is calculated and the mode with the highest energy concentration at a specific frequency is designated as the dominant mode. The results have been validated with the traditional approach by plotting mode shapes at each frequency. Clearly, this energy approach will be advantageous with the FEM analysis for vibration mode identification automatically.
{"title":"Identification of Vibration Modes of Quartz Crystal Plates with Proportion of Strain and Kinetic Energies","authors":"Qi Huang, R. Wu, Li-hong Wang, Longtao Xie, Jianke Du, T. Ma, Ji Wang","doi":"10.20855/ijav.2020.25.31671","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.31671","url":null,"abstract":"For the design of quartz crystal resonators, finding and determining the vibration modes have always been very important and cumbersome. Vibration modes are usually identified through plotting displacement patterns of each coupled modes and making comparisons. Over the years, there is not much improvement in the identification procedure while tremendous efforts have been made in refining the equations of the Mindlin plate theory to obtain more accurate results, such as the adoption of the Finite Element Method (FEM) by implementing the high-order Mindlin plate equations for efficient analysis. However, due to the old fashioned mode identification method, the FEM application is still inadequate and cannot be fully automated for this purpose. To have this situation improved, a method using the proportions of strain and kinetic energies to characterize the energy level of each vibration mode is proposed. With solutions of displacements, the energy distribution of each vibration mode is calculated and the mode with the highest energy concentration at a specific frequency is designated as the dominant mode. The results have been validated with the traditional approach by plotting mode shapes at each frequency. Clearly, this energy approach will be advantageous with the FEM analysis for vibration mode identification automatically.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"392-407"},"PeriodicalIF":1.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46272502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-30DOI: 10.20855/ijav.2020.25.31669
He Yu, Zai-ke Tian, Hong-ru Li, Baohua Xu, An Guoqing
Residual Useful Life (RUL) prediction is a key step of Condition-Based Maintenance (CBM). Deep learning-based techniques have shown wonderful prospects on RUL prediction, although their performances depends on heavy structures and parameter tuning strategies of these deep-learning models. In this paper, we propose a novel Deep Belief Network (DBN) model constructed by improved conditional Restrict Boltzmann Machines (RBMs) and apply it in RUL prediction for hydraulic pumps. DBN is a deep probabilistic digraph neural network that consists of multiple layers of RBMs. Since RBM is an undirected graph model and there is no communication among the nodes of the same layer, the deep feature extraction capability of the original DBN model can hardly ensure the accuracy of modeling continuous data. To address this issue, the DBN model is improved by replacing RBM with the Improved Conditional RBM (ICRBM) that adds timing linkage factors and constraint variables among the nodes of the same layers on the basis of RBM. The proposed model is applied to RUL prediction of hydraulic pumps, and the results show that the prediction model proposed in this paper has higher prediction accuracy compared with traditional DBNs, BP networks, support vector machines and modified DBNs such as DEBN and GC-DBN.
{"title":"A Novel Deep Belief Network Model Constructed by Improved Conditional RBMs and its Application in RUL Prediction for Hydraulic Pumps","authors":"He Yu, Zai-ke Tian, Hong-ru Li, Baohua Xu, An Guoqing","doi":"10.20855/ijav.2020.25.31669","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.31669","url":null,"abstract":"Residual Useful Life (RUL) prediction is a key step of Condition-Based Maintenance (CBM). Deep learning-based techniques have shown wonderful prospects on RUL prediction, although their performances depends on heavy structures and parameter tuning strategies of these deep-learning models. In this paper, we propose a novel Deep Belief Network (DBN) model constructed by improved conditional Restrict Boltzmann Machines (RBMs) and apply it in RUL prediction for hydraulic pumps. DBN is a deep probabilistic digraph neural network that consists of multiple layers of RBMs. Since RBM is an undirected graph model and there is no communication among the nodes of the same layer, the deep feature extraction capability of the original DBN model can hardly ensure the accuracy of modeling continuous data. To address this issue, the DBN model is improved by replacing RBM with the Improved Conditional RBM (ICRBM) that adds timing linkage factors and constraint variables among the nodes of the same layers on the basis of RBM. The proposed model is applied to RUL prediction of hydraulic pumps, and the results show that the prediction model proposed in this paper has higher prediction accuracy compared with traditional DBNs, BP networks, support vector machines and modified DBNs such as DEBN and GC-DBN.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"373-382"},"PeriodicalIF":1.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45928762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-30DOI: 10.20855/ijav.2020.25.31649
V. Nguyen, Zhenpeng Wu, Beiping Zhang, Zhang Run
To reduce shaking of a vibration screed system (VSS) and improve the paving performance of an asphalt paver (AP), the root-mean-square (RMS) acceleration responses at points on the front and rear screed floors are analyzed via an experimental method. A 3D nonlinear dynamic model of the VSS is also built to evaluate the influence of the dynamic parameters of the VSS on the compression efficiency, paving quality, and working stability of the AP based on the objective functions of the vertical, pitching, and rolling RMS values at the centre of gravity of the screed. The angular deviations, α and γ, of the tamper are then controlled to improve the paving performance. The research results show that the excitation frequency, ft, and both angular deviations, α and γ, of the tamper strongly affect the paving performance. The compression efficiency is quickly enhanced, while both paving quality and working stability are significantly reduced with increasing the excitation frequency ft and reducing the angular deviations. α and γ. and vice versa. Additionally, the screed shaking and paving performance of the AP are remarkably improved by control of the angular deviations, α and γ, under different working conditions.
{"title":"Vibration Analysis and Control of a Vibration Screed System for Asphalt Pavers","authors":"V. Nguyen, Zhenpeng Wu, Beiping Zhang, Zhang Run","doi":"10.20855/ijav.2020.25.31649","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.31649","url":null,"abstract":"To reduce shaking of a vibration screed system (VSS) and improve the paving performance of an asphalt paver (AP), the root-mean-square (RMS) acceleration responses at points on the front and rear screed floors are analyzed via an experimental method. A 3D nonlinear dynamic model of the VSS is also built to evaluate the influence of the dynamic parameters of the VSS on the compression efficiency, paving quality, and working stability of the AP based on the objective functions of the vertical, pitching, and rolling RMS values at the centre of gravity of the screed. The angular deviations, α and γ, of the tamper are then controlled to improve the paving performance. The research results show that the excitation frequency, ft, and both angular deviations, α and γ, of the tamper strongly affect the paving performance. The compression efficiency is quickly enhanced, while both paving quality and working stability are significantly reduced with increasing the excitation frequency ft and reducing the angular deviations. α and γ. and vice versa. Additionally, the screed shaking and paving performance of the AP are remarkably improved by control of the angular deviations, α and γ, under different working conditions.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"363-372"},"PeriodicalIF":1.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47688769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-30DOI: 10.20855/ijav.2020.25.31681
Qibo Mao, Shenquan Li, Shizuo Huang
Inertial actuators (IAs) are often used as control units in active noise and vibration control systems. It is wellknown that the IA’s natural frequency should be far below that of the structure under control to ensure good stability margins. However, under normal circumstances, an IA with low natural frequency either increases the additional weight or causes unwanted static displacement of the IA’s proof-mass. In this study, an IA with virtual mass is presented to reduce the IA’s natural frequency without changing its physical design. The virtual mass of the IA is realized by using the proof-mass acceleration feedback as a local loop within the IA. Thus, the IA’s natural frequency can be shifted to low frequency for active control application. The proposed IA with virtual mass is then applied to actively control a clamped beam’s vibration based on the velocity feedback control system. The experimental results show that the stability of the control system and the control performance can be improved significantly as the IA’s natural frequency is reduced with virtual mass.
{"title":"Inertial Actuator with Virtual Mass for Active Vibration Control","authors":"Qibo Mao, Shenquan Li, Shizuo Huang","doi":"10.20855/ijav.2020.25.31681","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.31681","url":null,"abstract":"Inertial actuators (IAs) are often used as control units in active noise and vibration control systems. It is wellknown that the IA’s natural frequency should be far below that of the structure under control to ensure good stability margins. However, under normal circumstances, an IA with low natural frequency either increases the additional weight or causes unwanted static displacement of the IA’s proof-mass. In this study, an IA with virtual mass is presented to reduce the IA’s natural frequency without changing its physical design. The virtual mass of the IA is realized by using the proof-mass acceleration feedback as a local loop within the IA. Thus, the IA’s natural frequency can be shifted to low frequency for active control application. The proposed IA with virtual mass is then applied to actively control a clamped beam’s vibration based on the velocity feedback control system. The experimental results show that the stability of the control system and the control performance can be improved significantly as the IA’s natural frequency is reduced with virtual mass.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"445-452"},"PeriodicalIF":1.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43386476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-30DOI: 10.20855/ijav.2020.25.21635
Md. Mehedi Hassan, M. I. Khan, Y. Hasemura, Md Mainul Islam
The comparisons of an AE source location performance of two widely used methods, time of arrival (TOA) and difference of arrival time (DOAT) have been analyzed in a complex planar multilayered surface. The complex surface has been prepared by covering a steel plate (SM400A) with a multilayered rubber material (Natural Rubber). The purpose of using this structure has been defined to get the comparable AE source location performance in a complicated signal propagation pathway. Both source location techniques have been conducted in a simulated AE wave propagating plane (300 mm � 200 mm in size) under Hsu-Nielsen method. Investigations reveal that the TOA technique gives several erroneous results along with good results. However, the DOAT method has produced all excellent results, even when using a complex surface. It was found since the TOA method is sensitive to constant velocity continuity, the present complex pathway leads to the velocity discontinuity, and thus, several incorrect results have been found. On the other hand, the DOAT method is dependent on the arrival time difference only, and therefore, it shows a higher performance in the source location, even in the presence of a complex structure.
{"title":"Performance Investigation of Two AE Source Location Techniques on a Planar Multilayer Structure","authors":"Md. Mehedi Hassan, M. I. Khan, Y. Hasemura, Md Mainul Islam","doi":"10.20855/ijav.2020.25.21635","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.21635","url":null,"abstract":"The comparisons of an AE source location performance of two widely used methods, time of arrival (TOA) and \u0000difference of arrival time (DOAT) have been analyzed in a complex planar multilayered surface. The complex \u0000surface has been prepared by covering a steel plate (SM400A) with a multilayered rubber material (Natural Rubber). The purpose of using this structure has been defined to get the comparable AE source location performance in a complicated signal propagation pathway. Both source location techniques have been conducted in a simulated AE wave propagating plane (300 mm � 200 mm in size) under Hsu-Nielsen method. Investigations reveal that the TOA technique gives several erroneous results along with good results. However, the DOAT method has produced all excellent results, even when using a complex surface. It was found since the TOA method is sensitive \u0000to constant velocity continuity, the present complex pathway leads to the velocity discontinuity, and thus, several incorrect results have been found. On the other hand, the DOAT method is dependent on the arrival time difference only, and therefore, it shows a higher performance in the source location, even in the presence of a complex structure.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"226-235"},"PeriodicalIF":1.0,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44944858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-30DOI: 10.20855/ijav.2020.25.21592
S. Hosseini, J. Marzbanrad
In this paper, a robust controller is designed with the help of a Magnetorheological fluid (MRF) for a semi-active engine mount. To do so, an 8-DOF vehicle model is chosen in which the road roughness and engine vibration are the disturbance inputs to the system and the mass of the vehicle is taken into accounts as an uncertainty. In addition, the maximum magnitude and frequency of the force applied to the vehicle body by the actuators are limited in the ranges of 0~1500N and 0~10Hz, respectively. To validate such a design, the proposed controller is compared with a PID controller. The comparison results show that the proposed controller has a good performance while dealing with uncertainties such a way that using it leads to transmitting the engine vibration frequency less than 6%. It is also shown that the vibrations due to disturbances entering the system are effectively reduced in the system including the proposed controller.
{"title":"Robust H-infinity Controller in a MRF Engine Mount for Improving the Vehicle Ride Comfort","authors":"S. Hosseini, J. Marzbanrad","doi":"10.20855/ijav.2020.25.21592","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.21592","url":null,"abstract":"In this paper, a robust controller is designed with the help of a Magnetorheological fluid (MRF) for a semi-active engine mount. To do so, an 8-DOF vehicle model is chosen in which the road roughness and engine vibration are the disturbance inputs to the system and the mass of the vehicle is taken into accounts as an uncertainty. In addition, the maximum magnitude and frequency of the force applied to the vehicle body by the actuators are limited in the ranges of 0~1500N and 0~10Hz, respectively. To validate such a design, the proposed controller is compared with a PID controller. The comparison results show that the proposed controller has a good performance while dealing with uncertainties such a way that using it leads to transmitting the engine vibration frequency less than 6%. It is also shown that the vibrations due to disturbances entering the system are effectively reduced in the system including the proposed controller.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"219-225"},"PeriodicalIF":1.0,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42299266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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