Structural cables are susceptible to the effects of high stress concentrations, corrosion, and wind-induced and other vibrations. Cables are normally the most critical elements in a cable-supported structure and their well-being is very important in the health of the structure. The laser-based vibration technique discussed in this paper is a means for health monitoring of cables and therefore the entire cable-supported structure. This technique uses a noncontact remote sensing laser vibrometer for collecting cable vibration data from distances of up to several hundreds of feet and determines its dynamic characteristics including vibration frequencies and damping ratios. A formulation specifically developed for structural cables capable of accounting for important cable parameters is then used to calculate the cable force. Estimated forces in the cables are compared to previously measured forces or designer’s prediction to detect patterns associated with damage to the cable itself and/or changes to the structure elsewhere. The estimated damping ratios are also compared against predefined criteria to infer about susceptibility against wind-induced vibrations and other vibrations. The technique provides rapid, effective, and accurate means for health monitoring of cable-supported structures. It determines the locations and elements with potential damage and the need for detailed and hands on inspection. To date, the technique has been used successfully for evaluation of twenty-five major bridges in the US and abroad. Though originally devised for condition assessment of stay cables, it has been developed further to include a variety of systems and conditions among them structural hanger ropes in suspension, truss, and arch supported bridges, ungrouted stay cables, cables with cross-ties, and external posttensioning tendons in segmental bridge construction. It has also found a valuable place in construction-phase activities for verification of forces in tension elements with minimal efforts. Future endeavors for automation and aerial delivery are being considered for this technique.
{"title":"A Laser-Based Noncontact Vibration Technique for Health Monitoring of Structural Cables: Background, Success, and New Developments","authors":"A. Mehrabi, Saman Farhangdoust","doi":"10.1155/2018/8640674","DOIUrl":"https://doi.org/10.1155/2018/8640674","url":null,"abstract":"Structural cables are susceptible to the effects of high stress concentrations, corrosion, and wind-induced and other vibrations. Cables are normally the most critical elements in a cable-supported structure and their well-being is very important in the health of the structure. The laser-based vibration technique discussed in this paper is a means for health monitoring of cables and therefore the entire cable-supported structure. This technique uses a noncontact remote sensing laser vibrometer for collecting cable vibration data from distances of up to several hundreds of feet and determines its dynamic characteristics including vibration frequencies and damping ratios. A formulation specifically developed for structural cables capable of accounting for important cable parameters is then used to calculate the cable force. Estimated forces in the cables are compared to previously measured forces or designer’s prediction to detect patterns associated with damage to the cable itself and/or changes to the structure elsewhere. The estimated damping ratios are also compared against predefined criteria to infer about susceptibility against wind-induced vibrations and other vibrations. The technique provides rapid, effective, and accurate means for health monitoring of cable-supported structures. It determines the locations and elements with potential damage and the need for detailed and hands on inspection. To date, the technique has been used successfully for evaluation of twenty-five major bridges in the US and abroad. Though originally devised for condition assessment of stay cables, it has been developed further to include a variety of systems and conditions among them structural hanger ropes in suspension, truss, and arch supported bridges, ungrouted stay cables, cables with cross-ties, and external posttensioning tendons in segmental bridge construction. It has also found a valuable place in construction-phase activities for verification of forces in tension elements with minimal efforts. Future endeavors for automation and aerial delivery are being considered for this technique.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/8640674","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42555722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The work of this paper is backgrounded by prediction or evaluation and control of mechanical self-noise in sonar array cavity. The vibratory power flow transmission analysis is applied to reveal the overall vibration level of the fluid-structural coupled system. Through modal coupling analysis on the fluid-structural vibration of the fluid-filled enclosure with elastic boundaries, an efficient computational method is deduced to determine the vibratory power flow generated by exterior excitations on the outside surface of the elastic structure, including the total power flow entering into the fluid-structural coupled system and the net power flow transmitted into the hydroacoustic field. Characteristics of the coupled natural frequencies and modals are investigated by a numerical example of a rectangular water-filled cavity with five acoustic rigid walls and one elastic panel. Influential factors of power flow transmission characteristics are further discussed with the purpose of overall evaluation and reduction of the cavity water sound energy.
{"title":"Research on Power Flow Transmission through Elastic Structure into a Fluid-Filled Enclosure","authors":"H. Rui, Li Chuangye, J. Laizhao, W. Weike","doi":"10.1155/2018/5273280","DOIUrl":"https://doi.org/10.1155/2018/5273280","url":null,"abstract":"The work of this paper is backgrounded by prediction or evaluation and control of mechanical self-noise in sonar array cavity. The vibratory power flow transmission analysis is applied to reveal the overall vibration level of the fluid-structural coupled system. Through modal coupling analysis on the fluid-structural vibration of the fluid-filled enclosure with elastic boundaries, an efficient computational method is deduced to determine the vibratory power flow generated by exterior excitations on the outside surface of the elastic structure, including the total power flow entering into the fluid-structural coupled system and the net power flow transmitted into the hydroacoustic field. Characteristics of the coupled natural frequencies and modals are investigated by a numerical example of a rectangular water-filled cavity with five acoustic rigid walls and one elastic panel. Influential factors of power flow transmission characteristics are further discussed with the purpose of overall evaluation and reduction of the cavity water sound energy.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":"2018 1","pages":"1-16"},"PeriodicalIF":0.0,"publicationDate":"2018-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/5273280","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42745008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper deals with the development of a numerical model, based on the Finite Element (FE) theory for the prediction of the squeal frequency of a railway disc brake. The analytical background has been discussed and presented, as well as the most efficient methods for evaluating the system stability; the attention has been paid particularly to the complex eigenvalues method, which has been adopted within this paper to investigate the railway disc brake system. Numerical results have been compared with measurements from experimental tests in order to validate the proposed numerical approach. At the end of this work, a sensitivity analysis, aimed at understanding the effects of some physical parameters influencing the stability of the brake system and the squeal propensity, has been carried out.
{"title":"Squeal Frequency of a Railway Disc Brake Evaluation by FE Analyses","authors":"F. Cascetta, F. Caputo, A. Luca","doi":"10.1155/2018/4692570","DOIUrl":"https://doi.org/10.1155/2018/4692570","url":null,"abstract":"This paper deals with the development of a numerical model, based on the Finite Element (FE) theory for the prediction of the squeal frequency of a railway disc brake. The analytical background has been discussed and presented, as well as the most efficient methods for evaluating the system stability; the attention has been paid particularly to the complex eigenvalues method, which has been adopted within this paper to investigate the railway disc brake system. Numerical results have been compared with measurements from experimental tests in order to validate the proposed numerical approach. At the end of this work, a sensitivity analysis, aimed at understanding the effects of some physical parameters influencing the stability of the brake system and the squeal propensity, has been carried out.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":" ","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2018-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/4692570","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48129861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study the structure of the seismic radiation in the far field produced by an explosive column. Using an asymptotic solution for the far field of vibration (Heelan’s solution), we find analytical expressions to the peak particle velocity (PPV) diagrams. These results are extended to the case of a charge with finite velocity of detonation.
{"title":"Asymptotic Structure of the Seismic Radiation from an Explosive Column","authors":"Marco Rosales-Vera, I. Piñeyro, G. Pinilla","doi":"10.1155/2018/9681465","DOIUrl":"https://doi.org/10.1155/2018/9681465","url":null,"abstract":"We study the structure of the seismic radiation in the far field produced by an explosive column. Using an asymptotic solution for the far field of vibration (Heelan’s solution), we find analytical expressions to the peak particle velocity (PPV) diagrams. These results are extended to the case of a charge with finite velocity of detonation.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":"2018 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2018-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/9681465","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48437727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soldiers and supporting engineers are frequently exposed to high low-frequency (<500 Hz) cabin noise in military vehicles. Despite the use of commercial hearing protection devices, the risk of auditory damage is still imminent because the devices may not be optimally customised for such applications. This study considers flax fibre-reinforced polypropylene (Flax-PP) as an alternative to the material selection for the ear cups of commercial earmuffs, which are typically made of acrylonitrile butadiene styrene (ABS). Different weaving configurations (woven and nonwoven) and various noise environments (pink noise, cabin booming noise, and firing noise) were considered to investigate the feasibility of the proposed composite earmuffs for low-frequency noise reduction. The remaining assembly components of the earmuff were kept consistent with those of a commercial earmuff, which served as a benchmark for results comparison. In contrast to the commercial earmuff, the composite earmuffs were shown to be better in mitigating low-frequency noise by up to 16.6 dB, while compromising midfrequency acoustical performance. Consequently, the proposed composite earmuffs may be an alternative for low-frequency noise reduction in vehicle cabins, at airports, and at construction sites involving heavy machineries.
{"title":"Low-Frequency Noise Reduction by Earmuffs with Flax Fibre-Reinforced Polypropylene Ear Cups","authors":"L. Ang, L. Tran, Steve Phillips, Y. Koh, H. Lee","doi":"10.1155/2018/2057820","DOIUrl":"https://doi.org/10.1155/2018/2057820","url":null,"abstract":"Soldiers and supporting engineers are frequently exposed to high low-frequency (<500 Hz) cabin noise in military vehicles. Despite the use of commercial hearing protection devices, the risk of auditory damage is still imminent because the devices may not be optimally customised for such applications. This study considers flax fibre-reinforced polypropylene (Flax-PP) as an alternative to the material selection for the ear cups of commercial earmuffs, which are typically made of acrylonitrile butadiene styrene (ABS). Different weaving configurations (woven and nonwoven) and various noise environments (pink noise, cabin booming noise, and firing noise) were considered to investigate the feasibility of the proposed composite earmuffs for low-frequency noise reduction. The remaining assembly components of the earmuff were kept consistent with those of a commercial earmuff, which served as a benchmark for results comparison. In contrast to the commercial earmuff, the composite earmuffs were shown to be better in mitigating low-frequency noise by up to 16.6 dB, while compromising midfrequency acoustical performance. Consequently, the proposed composite earmuffs may be an alternative for low-frequency noise reduction in vehicle cabins, at airports, and at construction sites involving heavy machineries.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":"2018 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2018-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2018/2057820","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45150808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Dwinovantyo, H. Manik, T. Prartono, S. Susilohadi
The application of Acoustic Doppler Current Profiler (ADCP) can be used not only for measuring ocean currents, but also for quantifying suspended sediment concentrations (SSC) from acoustic backscatter strength based on sonar principle. Suspended sediment has long been recognized as the largest sources of sea contaminant and must be considered as one of the important parameters in water quality of seawater. This research was to determine SSC from measured acoustic backscattered intensity of static and mobile ADCP. In this study, vertically mounted 400 kHz and 750 kHz static ADCP were deployed in Lembeh Strait, North Sulawesi. A mobile ADCP 307.2 kHz was also mounted on the boat and moved to the predefined cross-section, accordingly. The linear regression analysis of echo intensity measured by ADCP and by direct measurement methods showed that ADCP is a reliable method to measure SSC with correlation coefficient ( ) 0.92. Higher SSC was observed in low water compared to that in high water and near port area compared to those in observed areas. All of this analysis showed that the combination of static and mobile ADCP methods produces reasonably good spatial and temporal data of SSC.
{"title":"Quantification and Analysis of Suspended Sediments Concentration Using Mobile and Static Acoustic Doppler Current Profiler Instruments","authors":"A. Dwinovantyo, H. Manik, T. Prartono, S. Susilohadi","doi":"10.1155/2017/4890421","DOIUrl":"https://doi.org/10.1155/2017/4890421","url":null,"abstract":"The application of Acoustic Doppler Current Profiler (ADCP) can be used not only for measuring ocean currents, but also for quantifying suspended sediment concentrations (SSC) from acoustic backscatter strength based on sonar principle. Suspended sediment has long been recognized as the largest sources of sea contaminant and must be considered as one of the important parameters in water quality of seawater. This research was to determine SSC from measured acoustic backscattered intensity of static and mobile ADCP. In this study, vertically mounted 400 kHz and 750 kHz static ADCP were deployed in Lembeh Strait, North Sulawesi. A mobile ADCP 307.2 kHz was also mounted on the boat and moved to the predefined cross-section, accordingly. The linear regression analysis of echo intensity measured by ADCP and by direct measurement methods showed that ADCP is a reliable method to measure SSC with correlation coefficient ( ) 0.92. Higher SSC was observed in low water compared to that in high water and near port area compared to those in observed areas. All of this analysis showed that the combination of static and mobile ADCP methods produces reasonably good spatial and temporal data of SSC.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":"2017 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"2017-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2017/4890421","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41544325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shreedhar Kolekar, K. Venkatesh, J. Oh, Seung-bok Choi
This study presents experimental results of the vibration parameters of a sandwich beam featuring magnetorheological (MR) fluid as core material. For simplicity, the sandwich beam is considered as a single-degree-of-freedom (SDOF) system and the governing equation is derived in time and frequency domains. Then, from the governing equation, the vibration parameters which can be controllable by external stimuli are defined or obtained. These are the field-dependent natural frequency, damping factor, loss factor, and quality factor of the sandwich beam. Subsequently, a sandwich beam incorporating with controllable MR fluid core is fabricated and tested to evaluate the vibration parameters. MR fluid is prepared using the engine oil, iron particles, and grease as an additive and it is filled into the void zone (core) of the sandwich beam. The fabricated beam is then tested at four different conditions and the vibration parameters are numerically identified at each test. It is shown that both the natural frequency and damping property can be tuned by controlling the intensity of the magnetic field applied to MR fluid domain.
{"title":"The Tenability of Vibration Parameters of a Sandwich Beam Featuring Controllable Core: Experimental Investigation","authors":"Shreedhar Kolekar, K. Venkatesh, J. Oh, Seung-bok Choi","doi":"10.1155/2017/5674032","DOIUrl":"https://doi.org/10.1155/2017/5674032","url":null,"abstract":"This study presents experimental results of the vibration parameters of a sandwich beam featuring magnetorheological (MR) fluid as core material. For simplicity, the sandwich beam is considered as a single-degree-of-freedom (SDOF) system and the governing equation is derived in time and frequency domains. Then, from the governing equation, the vibration parameters which can be controllable by external stimuli are defined or obtained. These are the field-dependent natural frequency, damping factor, loss factor, and quality factor of the sandwich beam. Subsequently, a sandwich beam incorporating with controllable MR fluid core is fabricated and tested to evaluate the vibration parameters. MR fluid is prepared using the engine oil, iron particles, and grease as an additive and it is filled into the void zone (core) of the sandwich beam. The fabricated beam is then tested at four different conditions and the vibration parameters are numerically identified at each test. It is shown that both the natural frequency and damping property can be tuned by controlling the intensity of the magnetic field applied to MR fluid domain.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":" ","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2017-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2017/5674032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49377629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jihad Al-Oudatallah, F. Abboud, Mazen Khoury, H. Ibrahim
Overlapping signals separation is a difficult problem, where time windowing is unable to separate signals overlapping in time and frequency domain filtering is unable to separate signals with overlapping spectra. In this work, a simulation under MATLAB is implemented to illustrate the concept of overlapping signals. We propose an approach for resolving overlapping signals based on Fourier transform and inverse Fourier transform. The proposed approach is tested under MATLAB, and the simulation results validate the effectiveness and the accuracy of the proposed approach. The approach is developed using Gerchberg superresolution technique to cope with signals with low signal-to-noise ratio. For practical work, an echo shape determination is required to apply the proposed technique. The experimental results show accurate localization of multiple targets.
{"title":"Overlapping Signal Separation Method Using Superresolution Technique Based on Experimental Echo Shape","authors":"Jihad Al-Oudatallah, F. Abboud, Mazen Khoury, H. Ibrahim","doi":"10.1155/2017/7132038","DOIUrl":"https://doi.org/10.1155/2017/7132038","url":null,"abstract":"Overlapping signals separation is a difficult problem, where time windowing is unable to separate signals overlapping in time and frequency domain filtering is unable to separate signals with overlapping spectra. In this work, a simulation under MATLAB is implemented to illustrate the concept of overlapping signals. We propose an approach for resolving overlapping signals based on Fourier transform and inverse Fourier transform. The proposed approach is tested under MATLAB, and the simulation results validate the effectiveness and the accuracy of the proposed approach. The approach is developed using Gerchberg superresolution technique to cope with signals with low signal-to-noise ratio. For practical work, an echo shape determination is required to apply the proposed technique. The experimental results show accurate localization of multiple targets.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":" ","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2017-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2017/7132038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48462639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yue Hu, Xilu Zhao, Takao Yamaguchi, M. Sasajima, Tatsushi Sasanuma, A. Hara
Loudspeakers are designed for reproducing the original sound field as faithfully as possible. In order to faithfully reproduce sound, it is important to understand the relationships among the physical characteristics of the loudspeaker. This paper focuses on the cone, the edge, and the behavior of air around the voice coil, which are important elements in the design of cone loudspeakers and evaluates their effects on the acoustic characteristics of the loudspeaker.
{"title":"Effects of the Cone and Edge on the Acoustic Characteristics of a Cone Loudspeaker","authors":"Yue Hu, Xilu Zhao, Takao Yamaguchi, M. Sasajima, Tatsushi Sasanuma, A. Hara","doi":"10.1155/2017/2792376","DOIUrl":"https://doi.org/10.1155/2017/2792376","url":null,"abstract":"Loudspeakers are designed for reproducing the original sound field as faithfully as possible. In order to faithfully reproduce sound, it is important to understand the relationships among the physical characteristics of the loudspeaker. This paper focuses on the cone, the edge, and the behavior of air around the voice coil, which are important elements in the design of cone loudspeakers and evaluates their effects on the acoustic characteristics of the loudspeaker.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":"2017 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2017-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2017/2792376","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46008983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Vincenzo Rotondella, A. Merulla, A. Baldini, S. Mantovani
This paper presents a comparison between the experimental investigation and the Finite Element (FE) modal analysis of an automotive rear subframe. A modal correlation between the experimental data and the forecasts is performed. The present numerical model constitutes a predictive methodology able to forecast the experimental dynamic behaviour of the structure. The actual structure is excited with impact hammers and the modal response of the subframe is collected and evaluated by the PolyMAX algorithm. Both the FE model and the structural performance of the subframe are defined according to the Ferrari S.p.A. internal regulations. In addition, a novel modelling technique for welded joints is proposed that represents an extension of ACM2 approach, formulated for spot weld joints in dynamic analysis. Therefore, the Modal Assurance Criterion (MAC) is considered the optimal comparison index for the numerical-experimental correlation. In conclusion, a good numerical-experimental agreement from 50 Hz up to 500 Hz has been achieved by monitoring various dynamic parameters such as the natural frequencies, the mode shapes, and frequency response functions (FRFs) of the structure that represent a validation of this FE model for structural dynamic applications.
{"title":"Dynamic Modal Correlation of an Automotive Rear Subframe, with Particular Reference to the Modelling of Welded Joints","authors":"Vincenzo Rotondella, A. Merulla, A. Baldini, S. Mantovani","doi":"10.1155/2017/8572674","DOIUrl":"https://doi.org/10.1155/2017/8572674","url":null,"abstract":"This paper presents a comparison between the experimental investigation and the Finite Element (FE) modal analysis of an automotive rear subframe. A modal correlation between the experimental data and the forecasts is performed. The present numerical model constitutes a predictive methodology able to forecast the experimental dynamic behaviour of the structure. The actual structure is excited with impact hammers and the modal response of the subframe is collected and evaluated by the PolyMAX algorithm. Both the FE model and the structural performance of the subframe are defined according to the Ferrari S.p.A. internal regulations. In addition, a novel modelling technique for welded joints is proposed that represents an extension of ACM2 approach, formulated for spot weld joints in dynamic analysis. Therefore, the Modal Assurance Criterion (MAC) is considered the optimal comparison index for the numerical-experimental correlation. In conclusion, a good numerical-experimental agreement from 50 Hz up to 500 Hz has been achieved by monitoring various dynamic parameters such as the natural frequencies, the mode shapes, and frequency response functions (FRFs) of the structure that represent a validation of this FE model for structural dynamic applications.","PeriodicalId":44068,"journal":{"name":"Advances in Acoustics and Vibration","volume":"2017 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2017-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2017/8572674","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43814171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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