Thomas Cornett, Arka Chattopadhyay, M. Esmaeilpour
The design of a piezoelectric based device that uses interference bluff body to harvest wind energy is presented. Different prototypes including cantilever beam, cylinder as oscillating body, and cylinder as interference body were used and tested to investigate the effects of interference bluff body’s properties such as the size and distance from fix oscillating body on the performance of energy harvesting system. To compare the frequency of oscillating beam and its natural frequency, a numerical simulation based on Finite Element Method was performed to obtain the natural frequency of cantilever beam. It was found that the energy harvester can be greatly improved by placing a fixed bluff body as interference bluff body in upstream of the oscillating bluff body. Through experimental tests, this study reveals that both diameter of interference cylinder and the distance between oscillating and interference cylinder play a key role in the energy harvester’s performance. Moreover, two different modes of oscillation were observed, depending on diameter of interference cylinder and its distance from bluff body. For all cases, the Fast Fourier Transform (FFT) analysis was used to monitor the frequency of oscillating cylinder and these values were compared with the natural frequencies obtained by Finite Element Method’s analysis. The results showed that the shorter beams oscillate with a frequency of about 5 Hz, close to the natural frequency of 6Hz, while the longer beams oscillate with a frequency of about 2.2 Hz, close to the natural frequency of 2.17Hz.
{"title":"A Parametric Study of Piezoelectric Energy Harvesting by Vortex Induced Vibration of a Pair of Cylinders","authors":"Thomas Cornett, Arka Chattopadhyay, M. Esmaeilpour","doi":"10.1115/imece2021-71636","DOIUrl":"https://doi.org/10.1115/imece2021-71636","url":null,"abstract":"\u0000 The design of a piezoelectric based device that uses interference bluff body to harvest wind energy is presented. Different prototypes including cantilever beam, cylinder as oscillating body, and cylinder as interference body were used and tested to investigate the effects of interference bluff body’s properties such as the size and distance from fix oscillating body on the performance of energy harvesting system. To compare the frequency of oscillating beam and its natural frequency, a numerical simulation based on Finite Element Method was performed to obtain the natural frequency of cantilever beam. It was found that the energy harvester can be greatly improved by placing a fixed bluff body as interference bluff body in upstream of the oscillating bluff body. Through experimental tests, this study reveals that both diameter of interference cylinder and the distance between oscillating and interference cylinder play a key role in the energy harvester’s performance. Moreover, two different modes of oscillation were observed, depending on diameter of interference cylinder and its distance from bluff body. For all cases, the Fast Fourier Transform (FFT) analysis was used to monitor the frequency of oscillating cylinder and these values were compared with the natural frequencies obtained by Finite Element Method’s analysis. The results showed that the shorter beams oscillate with a frequency of about 5 Hz, close to the natural frequency of 6Hz, while the longer beams oscillate with a frequency of about 2.2 Hz, close to the natural frequency of 2.17Hz.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90655339","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}
Direct contact membrane distillation (DCMD) for desalination often suffers from membrane fouling, scaling, low permeate water flux and pore wetting. This study focuses on the integration of sonication with DCMD to mitigate these problems by enhancing mass flux and reducing temperature polarization. A computational fluid dynamic model has been developed for the evaluation of temperature polarization through sonication enhanced DCMD. The computational domain consists of two channels, i.e., feed and permeate. It has a length of 20 mm, with a height of 1 mm for each channel, and a membrane thickness of 130 μm. Laminar flow at a low Reynolds number is considered (Re □ 10), with feed and permeate flowing in a counter-flow arrangement at the same inlet velocity but different temperatures. The employed numerical model is unsteady non-isothermal governed by Navier–Stokes equations which are conjugated thermally with the polymeric membrane. The model is subjected to different sonication frequencies and amplitudes. It employs dynamic mesh in conjunction with temporal sound application with a very small-time step to solve the governing equations associated with the sonication effect. A sensitivity study based on the effect of different parameters on the performance of the direct contact membrane distillation is conducted. The parameters studied include the effect of sonication wave (amplitude and frequency), feed flow rate and feed temperature on temperature polarization coefficient (TPC) and mass flux. Results show that sonication definitely can ameliorate the DCMD performance seen as a gain in both TPC and mass flux.
{"title":"Performance Analysis of the Direct Contact Membrane Distillation Using Sonication Effect","authors":"Ussama Ali, M. Sajjad, I. Janajreh","doi":"10.1115/imece2021-73478","DOIUrl":"https://doi.org/10.1115/imece2021-73478","url":null,"abstract":"\u0000 Direct contact membrane distillation (DCMD) for desalination often suffers from membrane fouling, scaling, low permeate water flux and pore wetting. This study focuses on the integration of sonication with DCMD to mitigate these problems by enhancing mass flux and reducing temperature polarization. A computational fluid dynamic model has been developed for the evaluation of temperature polarization through sonication enhanced DCMD. The computational domain consists of two channels, i.e., feed and permeate. It has a length of 20 mm, with a height of 1 mm for each channel, and a membrane thickness of 130 μm. Laminar flow at a low Reynolds number is considered (Re □ 10), with feed and permeate flowing in a counter-flow arrangement at the same inlet velocity but different temperatures. The employed numerical model is unsteady non-isothermal governed by Navier–Stokes equations which are conjugated thermally with the polymeric membrane. The model is subjected to different sonication frequencies and amplitudes. It employs dynamic mesh in conjunction with temporal sound application with a very small-time step to solve the governing equations associated with the sonication effect. A sensitivity study based on the effect of different parameters on the performance of the direct contact membrane distillation is conducted. The parameters studied include the effect of sonication wave (amplitude and frequency), feed flow rate and feed temperature on temperature polarization coefficient (TPC) and mass flux. Results show that sonication definitely can ameliorate the DCMD performance seen as a gain in both TPC and mass flux.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87297141","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 laminated beam consisted of internally embedded d15 piezoelectric transducers in a pitch-catch configuration was fabricated with artificial delamination created at the interface of aluminum layers. The severity of damage was also varied to evaluate the effectiveness of the approach to detect delamination. A five-peak tone burst signal centered at 30 kHz was supplied to piezoelectric actuators throughout the experiment to produce antisymmetric waves in the laminate specimen. It was found that the closer the delamination occurred to the d15 PZT actuator the greater the change in signal increasing the probability to be identified using antisymmetric A0 wave mode. The analysis suggests that d15 PZT actuators should be placed in regions where delamination is likely to occur in laminated structures. Also, the propagation path of delamination was successfully predicted using a set of sensor signals processed using damage index methods including Pearson correlation coefficient and root mean square deviation. Evaluation of the results indicated that embedded d15 piezoelectric transducers exclusively couple to antisymmetric guided waves and can advance signal analysis for detection of delamination with ultrasonic structural health monitoring systems.
{"title":"Using d15 Piezoelectric Transducers for Ultrasonic Inspection of Delamination in Laminated Structures","authors":"H. Altammar, N. Salowitz","doi":"10.1115/imece2021-69157","DOIUrl":"https://doi.org/10.1115/imece2021-69157","url":null,"abstract":"\u0000 A laminated beam consisted of internally embedded d15 piezoelectric transducers in a pitch-catch configuration was fabricated with artificial delamination created at the interface of aluminum layers. The severity of damage was also varied to evaluate the effectiveness of the approach to detect delamination. A five-peak tone burst signal centered at 30 kHz was supplied to piezoelectric actuators throughout the experiment to produce antisymmetric waves in the laminate specimen. It was found that the closer the delamination occurred to the d15 PZT actuator the greater the change in signal increasing the probability to be identified using antisymmetric A0 wave mode. The analysis suggests that d15 PZT actuators should be placed in regions where delamination is likely to occur in laminated structures. Also, the propagation path of delamination was successfully predicted using a set of sensor signals processed using damage index methods including Pearson correlation coefficient and root mean square deviation. Evaluation of the results indicated that embedded d15 piezoelectric transducers exclusively couple to antisymmetric guided waves and can advance signal analysis for detection of delamination with ultrasonic structural health monitoring systems.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77791707","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}
Piezoelectric materials can be introduced as the additional components into the periodic structures as they can couple the mechanical and electric fields. However, the added mass is always constrained in practical engineering. A method is needed to guide how to posit the piezoelectric materials on the host structure under the mass limit. In this work, we develop a numerical method to determine the best distribution of piezoelectric materials on the host structure in order to control the wave propagation in the periodic structures. This is based on the fact that the propagation properties of the waves in the mechanical field can be regulated by electric impedance shunted to the piezoelectric materials. The coupling strength between the mechanical field and the electric field is quantified by the wave electromechanical coupling factor (WEMCF). It is related to the geometric of the piezoelectric materials only. As the periodic structures are constructed by the identical unit cell, the aim is to design the distribution of the piezoelectric materials on the unit cell. There is no constrain on the shape of piezoelectric materials in the optimized method, only the overall mass is limited. A linear weighing of stress components is proposed as the criterion to determine the priority of locations for piezoelectric materials. In the proposed method, the piezoelectric materials are introduced to the FE model by adding the additional piezoelectric element layers on the host structure. Details for handling polarization direction, electrode connection and the electric circuit parameters selection are also presented. A 1D thin-wall box beam is taken as the application example. Results show that the Bragg band gap can be adjusted to cover the target frequency range under the optimization design with the 10% mass limitation.
{"title":"Topological Optimization of Piezoelectric Materials for the Control of Wave Propagation in Periodic Structures","authors":"Jiahui Shi, Yu Fan, Lin Li","doi":"10.1115/imece2021-70964","DOIUrl":"https://doi.org/10.1115/imece2021-70964","url":null,"abstract":"\u0000 Piezoelectric materials can be introduced as the additional components into the periodic structures as they can couple the mechanical and electric fields. However, the added mass is always constrained in practical engineering. A method is needed to guide how to posit the piezoelectric materials on the host structure under the mass limit. In this work, we develop a numerical method to determine the best distribution of piezoelectric materials on the host structure in order to control the wave propagation in the periodic structures. This is based on the fact that the propagation properties of the waves in the mechanical field can be regulated by electric impedance shunted to the piezoelectric materials. The coupling strength between the mechanical field and the electric field is quantified by the wave electromechanical coupling factor (WEMCF). It is related to the geometric of the piezoelectric materials only. As the periodic structures are constructed by the identical unit cell, the aim is to design the distribution of the piezoelectric materials on the unit cell. There is no constrain on the shape of piezoelectric materials in the optimized method, only the overall mass is limited. A linear weighing of stress components is proposed as the criterion to determine the priority of locations for piezoelectric materials. In the proposed method, the piezoelectric materials are introduced to the FE model by adding the additional piezoelectric element layers on the host structure. Details for handling polarization direction, electrode connection and the electric circuit parameters selection are also presented. A 1D thin-wall box beam is taken as the application example. Results show that the Bragg band gap can be adjusted to cover the target frequency range under the optimization design with the 10% mass limitation.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76651146","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}
Damage identification for structural health monitoring (SHM) is explored through applying the x-vector speaker recognition technique in the structural domain. Using the progressive damage tests from the Z24 Bridge Benchmark dataset, a time-delay neural network (TDNN) is trained as an acoustic model to classify the provided global damage scenarios. The outputs of a pre-final layer, called x-vectors, are used as damage-sensitive features for identification of damage presence and mechanisms. Since the developed TDNN has learned the underpinning dynamics of the damage mechanisms in the Z24 tests, we apply it as a basis for damage identification problems tangential to the Z24 progressive damage classification task. Transfer learning and domain transfer are investigated via application of the developed TDNN towards local damage identification of the Z24 Bridge, and global and local damage identification for the unseen LANL SHM Alamosa Canyon Bridge, UC-Irvine Bridge Column, and Bookshelf studies. Supervised and unsupervised classification techniques are explored to assess this method, and strong results in damage detection are obtained for these SHM problems.
{"title":"An Exploration of X-Vectors for Damage Detection and Identification","authors":"Kyle L. Hom, H. Beigi, R. Betti","doi":"10.1115/imece2021-73324","DOIUrl":"https://doi.org/10.1115/imece2021-73324","url":null,"abstract":"\u0000 Damage identification for structural health monitoring (SHM) is explored through applying the x-vector speaker recognition technique in the structural domain. Using the progressive damage tests from the Z24 Bridge Benchmark dataset, a time-delay neural network (TDNN) is trained as an acoustic model to classify the provided global damage scenarios. The outputs of a pre-final layer, called x-vectors, are used as damage-sensitive features for identification of damage presence and mechanisms. Since the developed TDNN has learned the underpinning dynamics of the damage mechanisms in the Z24 tests, we apply it as a basis for damage identification problems tangential to the Z24 progressive damage classification task. Transfer learning and domain transfer are investigated via application of the developed TDNN towards local damage identification of the Z24 Bridge, and global and local damage identification for the unseen LANL SHM Alamosa Canyon Bridge, UC-Irvine Bridge Column, and Bookshelf studies. Supervised and unsupervised classification techniques are explored to assess this method, and strong results in damage detection are obtained for these SHM problems.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88507769","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 two-dimensional (2D) scan scheme is developed for a tracking continuously scanning laser Doppler vibrometer (CSLDV) system to scan the whole surface of a rotating structure excited by a random force. A tracking CSLDV system is developed to track a rotating structure and sweep its laser spot on its surface. The measured response of the structure using the 2D scan scheme of the tracking CSLDV system is considered as the response of the whole surface of the structure subject to random excitation. The measured response can be processed by an operational modal analysis (OMA) method called the improved demodulation method based on a rigorous model of a rotating plate to obtain modal parameters of the rotating structure, such as damped natural frequencies and undamped full-field mode shapes. Damped natural frequencies of the rotating structure are estimated from the fast Fourier transform of the measured response. Undamped full-field mode shapes are estimated by multiplying the measured response using sinusoids whose frequencies are estimated damped natural frequencies. Experimental investigation of the 2D scan scheme of the tracking CSLDV system and OMA method is conducted, and damped natural frequencies and undamped full-field mode shapes of a rotating fan blade with different constant speeds are estimated. It is theoretically and experimentally shown that damped natural frequencies of the rotating fan blade increases with its rotation speed.
{"title":"Operational Modal Analysis of a Rotating Structure Subject to Random Excitation Using a Tracking Continuously Scanning Laser Doppler Vibrometer via a Two-Dimensional Scan Scheme","authors":"L. Lyu, Wei-dong Zhu","doi":"10.1115/imece2021-71521","DOIUrl":"https://doi.org/10.1115/imece2021-71521","url":null,"abstract":"\u0000 A two-dimensional (2D) scan scheme is developed for a tracking continuously scanning laser Doppler vibrometer (CSLDV) system to scan the whole surface of a rotating structure excited by a random force. A tracking CSLDV system is developed to track a rotating structure and sweep its laser spot on its surface. The measured response of the structure using the 2D scan scheme of the tracking CSLDV system is considered as the response of the whole surface of the structure subject to random excitation. The measured response can be processed by an operational modal analysis (OMA) method called the improved demodulation method based on a rigorous model of a rotating plate to obtain modal parameters of the rotating structure, such as damped natural frequencies and undamped full-field mode shapes. Damped natural frequencies of the rotating structure are estimated from the fast Fourier transform of the measured response. Undamped full-field mode shapes are estimated by multiplying the measured response using sinusoids whose frequencies are estimated damped natural frequencies. Experimental investigation of the 2D scan scheme of the tracking CSLDV system and OMA method is conducted, and damped natural frequencies and undamped full-field mode shapes of a rotating fan blade with different constant speeds are estimated. It is theoretically and experimentally shown that damped natural frequencies of the rotating fan blade increases with its rotation speed.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84880649","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}
Activities in the mining industries as a result of rock blasting is the cause of extreme rock vibration which is considered a serious environmental hazard. In most cases, explosives are often used for the disintegration of rocks in opencast mine. One of the major challenges often experienced in mining industries is the case of ineffective use of explosive energy while performing such opencast operation, this could lead to disproportionate ground vibration, often measured by peak particle velocity (PPV). To reduce such ground vibration and environmental impediments, it is important to adopt creative models for the effective prediction of PPV. Considering the inevitable impact on rock mass, neighbouring structures and sometimes on human beings, an accurate prediction of ground vibrations and the evaluation of the aftereffects must be carried out prior to the actual blasting event. This research is an exposition of the prediction performance of a blast-induced PPV using a creative model -Fuzzy Mamdani Model (FMM) and a hybrid algorithm -Adaptive Neuro-Fuzzy Inference System (ANFIS), in mining operation. These models are employed to predict the blast-induced PPV, which is a measurement of the movement or vibration of a single earth particle as the shock waves from a particular location or blasting event moves through the system. Experimental dataset used in this research consists of three (3) input variables (change weight per delay, distance and scaled distance) and forty-four (44) record samples; the peak particle velocity represents the experimental result. The dataset is fed into MATLAB 2020 platform as input parameters. Results obtained using the creative and hybrid algorithms were compared based on root mean squared error (RMSE) and correlation coefficient between the experimental and predicted values of the PPV. The regression values obtained are 0.8487 and 0.97729 for the Fuzzy Mamdani model and ANFIS model respectively. From the result obtained, the best vibration prediction was achieved using the ANFIS model. It can be concluded that the ANFIS model gave a better prediction in terms of speed of computation and prediction accuracy. It is recommended that other hybrid algorithms and metaheuristic techniques be introduced and compared with the existing solution models for effective prediction of PPV in mining operations.
{"title":"Prediction of a Blast Induced Peak Particle Velocity in Mining Operations: A Fuzzy Mamdani and ANFIS-Based Evaluating Methodology","authors":"Mosa Machesa, L. Tartibu, M. Okwu","doi":"10.1115/imece2021-71256","DOIUrl":"https://doi.org/10.1115/imece2021-71256","url":null,"abstract":"\u0000 Activities in the mining industries as a result of rock blasting is the cause of extreme rock vibration which is considered a serious environmental hazard. In most cases, explosives are often used for the disintegration of rocks in opencast mine. One of the major challenges often experienced in mining industries is the case of ineffective use of explosive energy while performing such opencast operation, this could lead to disproportionate ground vibration, often measured by peak particle velocity (PPV). To reduce such ground vibration and environmental impediments, it is important to adopt creative models for the effective prediction of PPV. Considering the inevitable impact on rock mass, neighbouring structures and sometimes on human beings, an accurate prediction of ground vibrations and the evaluation of the aftereffects must be carried out prior to the actual blasting event. This research is an exposition of the prediction performance of a blast-induced PPV using a creative model -Fuzzy Mamdani Model (FMM) and a hybrid algorithm -Adaptive Neuro-Fuzzy Inference System (ANFIS), in mining operation. These models are employed to predict the blast-induced PPV, which is a measurement of the movement or vibration of a single earth particle as the shock waves from a particular location or blasting event moves through the system. Experimental dataset used in this research consists of three (3) input variables (change weight per delay, distance and scaled distance) and forty-four (44) record samples; the peak particle velocity represents the experimental result. The dataset is fed into MATLAB 2020 platform as input parameters. Results obtained using the creative and hybrid algorithms were compared based on root mean squared error (RMSE) and correlation coefficient between the experimental and predicted values of the PPV. The regression values obtained are 0.8487 and 0.97729 for the Fuzzy Mamdani model and ANFIS model respectively. From the result obtained, the best vibration prediction was achieved using the ANFIS model. It can be concluded that the ANFIS model gave a better prediction in terms of speed of computation and prediction accuracy. It is recommended that other hybrid algorithms and metaheuristic techniques be introduced and compared with the existing solution models for effective prediction of PPV in mining operations.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"78 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84070643","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 concepts of topological insulators in condensed matter physics have been harnessed in elastic metamaterials to obtain quasi-lossless and omnidirectional guiding of elastic waves. Initial studies concerning topological wave propagation in elastic metamaterials focused on localizing waves in 1D or 2D mechanical structures. More recent investigations involving topological metamaterials have uncovered methodologies to achieve unprecedented control of elastic waves in 3D structures. However, a 3D topological metamaterial that can be tuned online to expand functionalities and respond to external conditions has yet to be developed. To advance the state of the art, this research proposes a tunable 3D elastic metamaterial that enables the reconfiguration of a topological waveguide through the switching of metastable states. Through careful design of internal bistable elements in the metastable unit cell, a switching methodology is developed to obtain topologically distinct lattices and a full topological bandgap. Analysis of the dispersion relation for a supercell reveals the presence of a topological surface state at the interface of topologically distinct lattices. Full-scale finite element simulations illustrate topological wave propagation in a 3D structure with a path that can be tailored on-demand. The research outcomes presented in this paper could be beneficial to potential applications requiring programmable and robust energy transport in 3D mechanical structures and serve as an inspiration for further work in adaptive 3D topological metamaterials.
{"title":"Tunable Topological Wave Control in a Three-Dimensional Metastable Elastic Metamaterial","authors":"P. Dorin, Xiang-Rui Liu, K. W. Wang","doi":"10.1115/imece2021-69410","DOIUrl":"https://doi.org/10.1115/imece2021-69410","url":null,"abstract":"\u0000 The concepts of topological insulators in condensed matter physics have been harnessed in elastic metamaterials to obtain quasi-lossless and omnidirectional guiding of elastic waves. Initial studies concerning topological wave propagation in elastic metamaterials focused on localizing waves in 1D or 2D mechanical structures. More recent investigations involving topological metamaterials have uncovered methodologies to achieve unprecedented control of elastic waves in 3D structures. However, a 3D topological metamaterial that can be tuned online to expand functionalities and respond to external conditions has yet to be developed. To advance the state of the art, this research proposes a tunable 3D elastic metamaterial that enables the reconfiguration of a topological waveguide through the switching of metastable states. Through careful design of internal bistable elements in the metastable unit cell, a switching methodology is developed to obtain topologically distinct lattices and a full topological bandgap. Analysis of the dispersion relation for a supercell reveals the presence of a topological surface state at the interface of topologically distinct lattices. Full-scale finite element simulations illustrate topological wave propagation in a 3D structure with a path that can be tailored on-demand. The research outcomes presented in this paper could be beneficial to potential applications requiring programmable and robust energy transport in 3D mechanical structures and serve as an inspiration for further work in adaptive 3D topological metamaterials.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74629855","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}
In order to optimize the control strategy of the electric vehicle active voice (ASG) system and improve the authenticity of the simulation sound. This paper presents a sound control method for vehicle simulation based on harmonic algorithm. In this paper, based on the harmonic algorithm, starting from the virtual rotation rate (rpm) input by ASG system, according to the data collected from the actual internal combustion engine car, design control strategy and add shift point in the system. Determine the actual rotation rate of internal combustion engine car and the shift point of throttle opening, and through the python simulation curve. In this paper, using the offset proportional series algorithm to calculate the gear transmission ratio and optimize and simulate it. Since there is no shift or rotation rate mutation in electric vehicle, using quadratic function fitting to optimize the virtual rotation rate. Complete the “virtual rotation rate” transformation of ASG system based on real-time rotation rate of electric vehicle. Finally, the whole optimization system takes the “virtual rotation rate” of the real-time rotation rate of the actual electric vehicle as the input, and takes stm32f7 Series MCU as the hardware carrier. Organize engineers and students with sound quality experience to evaluate the simulated sound quality of internal combustion engine car. The results show that the control strategy proposed in this paper can realize the sound simulation of internal combustion engine car in the electric vehicle cab, and the optimized ASG system can better meet the majority of drivers’ preference for sound than the original ASG system.
{"title":"Research on Control Strategy of Automobile Simulate Sound Based on Harmonic Algorithm","authors":"Zhien Liu, Rong-pei Qin, Liping Xie, Kai Liu","doi":"10.1115/imece2021-70700","DOIUrl":"https://doi.org/10.1115/imece2021-70700","url":null,"abstract":"\u0000 In order to optimize the control strategy of the electric vehicle active voice (ASG) system and improve the authenticity of the simulation sound. This paper presents a sound control method for vehicle simulation based on harmonic algorithm. In this paper, based on the harmonic algorithm, starting from the virtual rotation rate (rpm) input by ASG system, according to the data collected from the actual internal combustion engine car, design control strategy and add shift point in the system. Determine the actual rotation rate of internal combustion engine car and the shift point of throttle opening, and through the python simulation curve. In this paper, using the offset proportional series algorithm to calculate the gear transmission ratio and optimize and simulate it. Since there is no shift or rotation rate mutation in electric vehicle, using quadratic function fitting to optimize the virtual rotation rate. Complete the “virtual rotation rate” transformation of ASG system based on real-time rotation rate of electric vehicle. Finally, the whole optimization system takes the “virtual rotation rate” of the real-time rotation rate of the actual electric vehicle as the input, and takes stm32f7 Series MCU as the hardware carrier. Organize engineers and students with sound quality experience to evaluate the simulated sound quality of internal combustion engine car. The results show that the control strategy proposed in this paper can realize the sound simulation of internal combustion engine car in the electric vehicle cab, and the optimized ASG system can better meet the majority of drivers’ preference for sound than the original ASG system.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74713543","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}
Zhan Pengming, Qin Xianrong, Zhang Qing, Sun Yuantao
In this paper, a novel output-only structural system identification method is proposed based on the decomposition of the response signal by applying newly developed symplectic geometry mode decomposition (SGMD). The SGMD can decompose the output signal into a limited of single component signals which are also called symplectic geometry components (SGCs) adaptively without determining too many parameters. Then the random decrement technique (RDT) is applied to extract the free decay responses from SGCs. Finally, the modal parameters such as modal frequency and damping ratio can be identified using the Hilbert transform (HT) method. To demonstrate the validity and effectiveness of the proposed method, a numerical example and a monitored quayside container crane structure are conducted. The modal parameters of those studies can be obtained accurately and effectively by using the proposed method.
{"title":"Output-Only Structural System Identification Based on Symplectic Geometry Mode Decomposition","authors":"Zhan Pengming, Qin Xianrong, Zhang Qing, Sun Yuantao","doi":"10.1115/imece2021-68740","DOIUrl":"https://doi.org/10.1115/imece2021-68740","url":null,"abstract":"\u0000 In this paper, a novel output-only structural system identification method is proposed based on the decomposition of the response signal by applying newly developed symplectic geometry mode decomposition (SGMD). The SGMD can decompose the output signal into a limited of single component signals which are also called symplectic geometry components (SGCs) adaptively without determining too many parameters. Then the random decrement technique (RDT) is applied to extract the free decay responses from SGCs. Finally, the modal parameters such as modal frequency and damping ratio can be identified using the Hilbert transform (HT) method. To demonstrate the validity and effectiveness of the proposed method, a numerical example and a monitored quayside container crane structure are conducted. The modal parameters of those studies can be obtained accurately and effectively by using the proposed method.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79411223","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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