Pub Date : 2020-03-30DOI: 10.20855/ijav.2020.25.11626
K. Renji, S. J. K. Florence, S. Deshpande
Honeycomb sandwich composite cylindrical shells are widely used in aerospace structures. Experimentally observed modal densities of such shells are not reported. In this work, modal densities of a typical honeycomb sandwich composite cylinder are obtained experimentally by measuring the drive point admittance. The results are in good agreement with those estimated theoretically that incorporated transverse shear deformation. Its limitations at higher frequencies are investigated and the frequency beyond which the estimation is in error is determined. The results provide an example to prove the need for measuring the imaginary part of the driving point admittance and using it in the determination of the modal densities of honeycomb sandwich-type structures. Experiments are carried out with two boundary conditions for the cylinder and the results provide experimental evidence for the fact that the modal densities at high frequencies do not depend on the boundary conditions. At higher frequencies, it is expected that both of the face sheets vibrate independently. This frequency can be approximately estimated as the fundamental bending mode frequency of the wall of the honeycomb core. The modal density determined through the measured driving point admittance will have a sharp reduction at this frequency and this feature can be used in identifying this phenomenon. The experimental results are in very good agreement with the above results.
{"title":"An Experimental Investigation of Modal Densities of Composite Honeycomb Sandwich Cylindrical Shells","authors":"K. Renji, S. J. K. Florence, S. Deshpande","doi":"10.20855/ijav.2020.25.11626","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.11626","url":null,"abstract":"Honeycomb sandwich composite cylindrical shells are widely used in aerospace structures. Experimentally observed modal densities of such shells are not reported. In this work, modal densities of a typical honeycomb sandwich composite cylinder are obtained experimentally by measuring the drive point admittance. The results are in good agreement with those estimated theoretically that incorporated transverse shear deformation. Its limitations at higher frequencies are investigated and the frequency beyond which the estimation is in error is determined. The results provide an example to prove the need for measuring the imaginary part of the driving point admittance and using it in the determination of the modal densities of honeycomb sandwich-type structures. Experiments are carried out with two boundary conditions for the cylinder and the results provide experimental evidence for the fact that the modal densities at high frequencies do not depend on the boundary conditions. At higher frequencies, it is expected that both of the face sheets vibrate independently. This frequency can be approximately estimated as the fundamental bending mode frequency of the wall of the honeycomb core. The modal density determined through the measured driving point admittance will have a sharp reduction at this frequency and this feature can be used in identifying this phenomenon. The experimental results are in very good agreement with the above results.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"112-120"},"PeriodicalIF":1.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43331021","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 : 2020-03-30DOI: 10.20855/ijav.2020.25.11490
M. H. Said, F. Tounsi, L. Rufer, B. Mezghani, L. Francis
This paper presents analytic and numerical modelling of a MEMS electrodynamic micro-sensor of dynamic pressure. Two coaxial planar inductors of different diameters are used in the proposed micro-sensor design. Using finite element analysis, the diaphragm resonant frequency and dynamic displacements are evaluated for different diaphragm thicknesses. Then, the total sensitivity is deduced by coupling different physical domains which contribute in the micro-sensor operation. A lumped element model is built in order to study the micro-sensor sensitivity and define the dynamic performance for different resonant frequencies. This model shows that the best sensitivity, within the mV/Pa range, is obtained around the resonant frequency when operation in the audible frequency range, and decreases to the μV/Pa range for ultrasonic frequencies. The obtained sensitivity curves prove that the undamped inductive micro-sensor can offer high pressure sensitivity within a narrow frequency bandwidth.
{"title":"Sensitivity and Performances Analysis of a Dynamic Pressure Narrow-Band Electrodynamic Micro-Sensor","authors":"M. H. Said, F. Tounsi, L. Rufer, B. Mezghani, L. Francis","doi":"10.20855/ijav.2020.25.11490","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.11490","url":null,"abstract":"This paper presents analytic and numerical modelling of a MEMS electrodynamic micro-sensor of dynamic pressure. Two coaxial planar inductors of different diameters are used in the proposed micro-sensor design. Using finite element analysis, the diaphragm resonant frequency and dynamic displacements are evaluated for different diaphragm thicknesses. Then, the total sensitivity is deduced by coupling different physical domains which contribute in the micro-sensor operation. A lumped element model is built in order to study the micro-sensor sensitivity and define the dynamic performance for different resonant frequencies. This model shows that the best sensitivity, within the mV/Pa range, is obtained around the resonant frequency when operation in the audible frequency range, and decreases to the μV/Pa range for ultrasonic frequencies. The obtained sensitivity curves prove that the undamped inductive micro-sensor can offer high pressure sensitivity within a narrow frequency bandwidth.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"17-26"},"PeriodicalIF":1.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47135017","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 : 2020-03-30DOI: 10.20855/ijav.2020.25.11604
S. Sepehrirahnama, Felix Bob Wijaya, D. Oon, E. Ong, H. Lee, K. Lim
In this hydroelasticity study, the fluid added-mass effect on a hemispherical shell structure under flexural vibration is investigated. The vibration response of the hemisphere is solved by using a commercial finite element software (ABAQUS) coupled with an in-house boundary element code that models the fluid as potential flow. The fluidstructure interaction is solved as a fully-coupled system by modal superposition to reduce the number of degrees of freedom. The need for an iterative scheme to pass displacement/force information between the two solvers is avoided by direct coupling between the fluid and structure equations. The numerical results on the downward shift in natural frequencies due to added-mass effect compare well with vibration measurements conducted on a stainless-steel bowl with interior and exterior fluid. For water and soap-water solution used in the experiments, the fluid viscosity (varying over a wide range) did not have any significant effect on the wet natural frequencies. This is due to the small viscous boundary layer (milimetre scale) compared to the nominal size of the bowl in centimetres. For such cases, the fluid-added mass only depends on the density of the fluid and the use of potential flow in the numerical model is applicable.
{"title":"Fluid Added-Mass Effect on Flexural Vibration of Hemispherical Shell Structure","authors":"S. Sepehrirahnama, Felix Bob Wijaya, D. Oon, E. Ong, H. Lee, K. Lim","doi":"10.20855/ijav.2020.25.11604","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.11604","url":null,"abstract":"In this hydroelasticity study, the fluid added-mass effect on a hemispherical shell structure under flexural vibration is investigated. The vibration response of the hemisphere is solved by using a commercial finite element software (ABAQUS) coupled with an in-house boundary element code that models the fluid as potential flow. The fluidstructure interaction is solved as a fully-coupled system by modal superposition to reduce the number of degrees of freedom. The need for an iterative scheme to pass displacement/force information between the two solvers is avoided by direct coupling between the fluid and structure equations. The numerical results on the downward shift in natural frequencies due to added-mass effect compare well with vibration measurements conducted on a stainless-steel bowl with interior and exterior fluid. For water and soap-water solution used in the experiments, the fluid viscosity (varying over a wide range) did not have any significant effect on the wet natural frequencies. This is due to the small viscous boundary layer (milimetre scale) compared to the nominal size of the bowl in centimetres. For such cases, the fluid-added mass only depends on the density of the fluid and the use of potential flow in the numerical model is applicable.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"104-111"},"PeriodicalIF":1.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46728133","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 : 2020-03-30DOI: 10.20855/ijav.2020.25.11512
Dragan B. Sekulic
This paper analyses the effect of the waviness parameter w on the oscillatory comfort of bus passengers for one road in good condition. The analysis is carried out by a validated nonlinear oscillatory 16 degrees of freedom (DOF) bus model defined in the software Matlab/Simulink and procedure from ISO 2631/1997 standard. The root-mean-square (RMS ) values of the weighted vertical accelerations from the passengers’ seats increase with the increase in the parameter w. On the other hand, the RMS values of the weighted vertical accelerations from bus floor decreased with the increase in the parameter w. The best oscillatory comfort has a passenger in the middle part of the bus, and the worst has a passenger in the rear part of the bus. The intensities of the vertical accelerations from the bus floor are mainly concentrated into two frequency ranges, 0 ÷ 2.5 Hz and 5 ÷ 10 Hz. The passenger seats are dampened with vertical vibrations above 4 Hz. For the narrow range w = 1.5÷ 2.3, nominal value of the waviness parameter (w = 2) is sufficiently precise in assessment of the bus passengers’ oscillatory comfort.
{"title":"Influence of Road Roughness Wavelengths on Bus Passengers' Oscillatory Comfort","authors":"Dragan B. Sekulic","doi":"10.20855/ijav.2020.25.11512","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.11512","url":null,"abstract":"This paper analyses the effect of the waviness parameter w on the oscillatory comfort of bus passengers for one road in good condition. The analysis is carried out by a validated nonlinear oscillatory 16 degrees of freedom (DOF) bus model defined in the software Matlab/Simulink and procedure from ISO 2631/1997 standard. The root-mean-square (RMS ) values of the weighted vertical accelerations from the passengers’ seats increase with the increase in the parameter w. On the other hand, the RMS values of the weighted vertical accelerations from bus floor decreased with the increase in the parameter w. The best oscillatory comfort has a passenger in the middle part of the bus, and the worst has a passenger in the rear part of the bus. The intensities of the vertical accelerations from the bus floor are mainly concentrated into two frequency ranges, 0 ÷ 2.5 Hz and 5 ÷ 10 Hz. The passenger seats are dampened with vertical vibrations above 4 Hz. For the narrow range w = 1.5÷ 2.3, nominal value of the waviness parameter (w = 2) is sufficiently precise in assessment of the bus passengers’ oscillatory comfort.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"41-53"},"PeriodicalIF":1.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46061657","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 : 2020-03-30DOI: 10.20855/ijav.2020.25.4e95
Li Cheng
{"title":"Sound Absorptions by Micro-Perforated Panels","authors":"Li Cheng","doi":"10.20855/ijav.2020.25.4e95","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.4e95","url":null,"abstract":"","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"2-2"},"PeriodicalIF":1.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45495634","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 : 2020-03-30DOI: 10.20855/ijav.2020.25.11603
S. Kaul
This paper examines a model to investigate the impact of a vibration isolation system on the planar (in-plane) dynamics of a motorcycle. While it is not very common, a vibration isolation system is used in some motorcycles to mitigate vibrations resulting from the shaking forces of the engine. For such layouts, the powertrain is assembled to the frame through the vibration isolation system that typically consists of two to four isolators. It is critical to comprehend the influence of the isolation system on the overall dynamic characteristics of the motorcycle due to the coupled dynamics of the rear suspension, the isolation system, and the rear unsprung mass. The influence of a vibration isolation system on the in-plane dynamics is analysed by using a relatively simple model that has been developed in this study. This model has been used to evaluate the influence of the isolation system on natural modes, transmissibility, and ride comfort. Results indicate that the use of a vibration isolation system couples the rear unsprung hop to the pitch motion of the powertrain with a slight increase in the corresponding natural frequency. Results indicate that the use of a vibration isolation system directly affects handling of the motorcycle. Furthermore, results indicate that the pitch of the sprung mass and the hop of the rear unsprung mass are particularly influenced by the vibration isolation system. The model presented in this paper could be useful in the early stages of the design process to compare the rigidly mounted powertrain to different layouts of the vibration isolation system.
{"title":"Influence of a Vibration Isolation System on Planar Dynamics of a Motorcycle","authors":"S. Kaul","doi":"10.20855/ijav.2020.25.11603","DOIUrl":"https://doi.org/10.20855/ijav.2020.25.11603","url":null,"abstract":"This paper examines a model to investigate the impact of a vibration isolation system on the planar (in-plane) dynamics of a motorcycle. While it is not very common, a vibration isolation system is used in some motorcycles to mitigate vibrations resulting from the shaking forces of the engine. For such layouts, the powertrain is assembled to the frame through the vibration isolation system that typically consists of two to four isolators. It is critical to comprehend the influence of the isolation system on the overall dynamic characteristics of the motorcycle due to the coupled dynamics of the rear suspension, the isolation system, and the rear unsprung mass. The influence of a vibration isolation system on the in-plane dynamics is analysed by using a relatively simple model that has been developed in this study. This model has been used to evaluate the influence of the isolation system on natural modes, transmissibility, and ride comfort. Results indicate that the use of a vibration isolation system couples the rear unsprung hop to the pitch motion of the powertrain with a slight increase in the corresponding natural frequency. Results indicate that the use of a vibration isolation system directly affects handling of the motorcycle. Furthermore, results indicate that the pitch of the sprung mass and the hop of the rear unsprung mass are particularly influenced by the vibration isolation system. The model presented in this paper could be useful in the early stages of the design process to compare the rigidly mounted powertrain to different layouts of the vibration isolation system.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"25 1","pages":"96-103"},"PeriodicalIF":1.0,"publicationDate":"2020-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41719645","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 : 2019-12-31DOI: 10.20855/ijav.2019.24.41526
Yuan Xianju, Tian Tianyu, Lin Hongtao, Tian-yu Qiu
Magnetorheological (MR) dampers whose nonlinear hysteresis is a rather complicated phenomenon have been widespread in mechanical systems, automobile shock absorbers, the civil engineering, etc. The understanding of such a behaviour is helpful to control effectively and utilize maximum advantages of MR dampers. It is vitally important to construct parametric models used to develop control algorithms. Hence, the current study aims at developing a parametric model which exhibits considerably better predictions than that of more complicated models. In addition to achieving such a target, a simple algebraic model including only an exponential function, a hyperbolic tangent function, and other algebraic expressions can be able to capture the non-linear hysteresis adequately. Compared to an existing algebraic model and the experimental dataset, the proposed model is a reliable one.
{"title":"A New Model for Characterizing Nonlinear Hysteresis of Magnetorheological Fluid Damper","authors":"Yuan Xianju, Tian Tianyu, Lin Hongtao, Tian-yu Qiu","doi":"10.20855/ijav.2019.24.41526","DOIUrl":"https://doi.org/10.20855/ijav.2019.24.41526","url":null,"abstract":"Magnetorheological (MR) dampers whose nonlinear hysteresis is a rather complicated phenomenon have been widespread in mechanical systems, automobile shock absorbers, the civil engineering, etc. The understanding of such a behaviour is helpful to control effectively and utilize maximum advantages of MR dampers. It is vitally important to construct parametric models used to develop control algorithms. Hence, the current study aims at developing a parametric model which exhibits considerably better predictions than that of more complicated models. In addition to achieving such a target, a simple algebraic model including only an exponential function, a hyperbolic tangent function, and other algebraic expressions can be able to capture the non-linear hysteresis adequately. Compared to an existing algebraic model and the experimental dataset, the proposed model is a reliable one.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"24 1","pages":"784-791"},"PeriodicalIF":1.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48821620","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 : 2019-12-31DOI: 10.20855/ijav.2019.24.41432
T. K. Joseph, K. Renji, K. Venkatraman
The loss factor of a structure is significantly improved by using constrained damping treatment. For a mass efficient design, the damping material is to be applied at suitable locations. The studies reported in literature use the modal strain energy distribution in the viscoelastic material or the strain energy distribution in the base structure as tools to arrive at these suitable locations for the damping treatment. It is shown here that the regions identified through the above criteria need not be suitable for certain bending modes of vibration. A new approach is proposed in which the strain in the viscoelastic material and the angle of flexure are shown to be more reliable in arriving at the locations for the damping treatment. Providing damping layers at identified locations using these parameters results in significant loss factors with minimal added mass.
{"title":"On the Region for the Application of Passive Damping Treatment and Loss Factor Enhancement","authors":"T. K. Joseph, K. Renji, K. Venkatraman","doi":"10.20855/ijav.2019.24.41432","DOIUrl":"https://doi.org/10.20855/ijav.2019.24.41432","url":null,"abstract":"The loss factor of a structure is significantly improved by using constrained damping treatment. For a mass efficient design, the damping material is to be applied at suitable locations. The studies reported in literature use the modal strain energy distribution in the viscoelastic material or the strain energy distribution in the base structure as tools to arrive at these suitable locations for the damping treatment. It is shown here that the regions identified through the above criteria need not be suitable for certain bending modes of vibration. A new approach is proposed in which the strain in the viscoelastic material and the angle of flexure are shown to be more reliable in arriving at the locations for the damping treatment. Providing damping layers at identified locations using these parameters results in significant loss factors with minimal added mass.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"24 1","pages":"693-700"},"PeriodicalIF":1.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47154962","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 : 2019-12-31DOI: 10.20855/ijav.2019.24.41458
Yin Xuejun, Zhaohui Xu, Yang Yang, Yong Luo, Jian-li Wang
Guangzhou Asian Games Comprehensive Museum is one of the permanent buildings for the 2010 Guangzhou Asian Games, whose bowl-shaped main body is a steel structure with the largest cantilever length of more than 30 meters. The structure has a low natural frequency, so it tends to be excited by people synchronizing walking with amplification of resonance, which will affect the serviceability. A large amount of analysis and field-tests are performed for this historical museum with tuned mass dampers (TMDs) being used to reduce human walking induced vibration. The results showed that TMDs can control the structure vertical vibration effectively, with the efficiency of over 50%. The research results have obvious significance for similar projects.
{"title":"Human-Induced Vibration Control with TMDs for Guangzhou Asian Games Comprehensive Museum","authors":"Yin Xuejun, Zhaohui Xu, Yang Yang, Yong Luo, Jian-li Wang","doi":"10.20855/ijav.2019.24.41458","DOIUrl":"https://doi.org/10.20855/ijav.2019.24.41458","url":null,"abstract":"Guangzhou Asian Games Comprehensive Museum is one of the permanent buildings for the 2010 Guangzhou Asian Games, whose bowl-shaped main body is a steel structure with the largest cantilever length of more than 30 meters. The structure has a low natural frequency, so it tends to be excited by people synchronizing walking with amplification of resonance, which will affect the serviceability. A large amount of analysis and field-tests are performed for this historical museum with tuned mass dampers (TMDs) being used to reduce human walking induced vibration. The results showed that TMDs can control the structure vertical vibration effectively, with the efficiency of over 50%. The research results have obvious significance for similar projects.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"24 1","pages":"736-743"},"PeriodicalIF":1.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42069515","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 : 2019-12-31DOI: 10.20855/ijav.2019.24.41460
Chol-Hak Kim, Myong-jin Kim, Chol-Su Ri
In this paper, we described a method of designing ultrasonic transducer which simultaneously radiates two finiteamplitude ultrasonic waves to produce the secondary waves with high directivity. For nonlinear effects, it is necessary that the frequencies of two primary waves are coincident with natural frequencies of the ultrasonic transducer. The main problem here is to predict the resonance frequencies of the first mode as well as higher modes. While the first resonance frequency of the transducer can be estimated easily, it is not trivial to do higher ones. When the length of transducer is much greater than its diameter, this problem is reduced to one-dimensional and higher mode frequencies are nothing but multiples of the first mode frequency. However, such a case is seldom encountered. Using the transfer matrix method, we obtained the resonance frequencies of the transducer analytically and compared these with numerical results from the simulation. The theoretical and simulation results are in good agreement with the difference of 3–6kHz.
{"title":"Design of Ultrasonic Transducer for Secondary Wave Generations with High Directivity","authors":"Chol-Hak Kim, Myong-jin Kim, Chol-Su Ri","doi":"10.20855/ijav.2019.24.41460","DOIUrl":"https://doi.org/10.20855/ijav.2019.24.41460","url":null,"abstract":"In this paper, we described a method of designing ultrasonic transducer which simultaneously radiates two finiteamplitude ultrasonic waves to produce the secondary waves with high directivity. For nonlinear effects, it is necessary that the frequencies of two primary waves are coincident with natural frequencies of the ultrasonic transducer. The main problem here is to predict the resonance frequencies of the first mode as well as higher modes. While the first resonance frequency of the transducer can be estimated easily, it is not trivial to do higher ones. When the length of transducer is much greater than its diameter, this problem is reduced to one-dimensional and higher mode frequencies are nothing but multiples of the first mode frequency. However, such a case is seldom encountered. Using the transfer matrix method, we obtained the resonance frequencies of the transducer analytically and compared these with numerical results from the simulation. The theoretical and simulation results are in good agreement with the difference of 3–6kHz.","PeriodicalId":49185,"journal":{"name":"International Journal of Acoustics and Vibration","volume":"24 1","pages":"744-748"},"PeriodicalIF":1.0,"publicationDate":"2019-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46017146","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：