{"title":"Front Matter: Volume 10972","authors":"","doi":"10.1117/12.2534593","DOIUrl":"https://doi.org/10.1117/12.2534593","url":null,"abstract":"","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131928006","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}
{"title":"Nonlinear phased array imaging using phase (Conference Presentation)","authors":"A. Croxford, J. Potter, P. Blanloeuil","doi":"10.1117/12.2515808","DOIUrl":"https://doi.org/10.1117/12.2515808","url":null,"abstract":"","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"241 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126825313","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}
Topology has recently emerged as a principle governing unique wave transport phenomena through interface or edge modes that are impurity-immune and potentially unidirectional. In mechanics, these phenomena arise by marrying the notion of material and structure, and are expected to lead to functionalities at the mesoscale that are unattainable solely based on the properties of constituents. Beyond the mere notion of a material, these meta-structures draw their unique characteristics from their finite size and the existence of interfaces. The resulting structural assemblies are expected to feature unprecedented performance in terms of stress wave mitigation, wave guiding, acoustic absorption, and vibration isolation. The seminar illustrates investigations on the effects of nonlinearities on topological properties, and the study of quasi-periodic assemblies. Investigation of the effects of nonlinearities on topological properties allows the exploration of the appearance/robustness of edge and localized modes in the presence of nonlinearities. In addition, the study of lattices with quasi-periodic configurations uncover additional unique properties related to vibration localization in one-dimensional and two-dimensional systems. These can be as interesting if not more useful than the interface modes that are found in periodic structures, as the quasi-periodicity framework provides a consistent methodology that leads to vibration confinement in systems that are not ordered, but are described by deterministic property distributions. Beam and plate structures with quasiperiodic arrangements of grounding springs and lumped masses are presented as structural components which support a variety of localized modes and that are suitable for the experimental characterization of the dynamic behavior of these configurations.
{"title":"Dynamics of topological metastructures: nonlinearities and quasi-periodicity (Conference Presentation)","authors":"M. Ruzzene","doi":"10.1117/12.2515686","DOIUrl":"https://doi.org/10.1117/12.2515686","url":null,"abstract":"Topology has recently emerged as a principle governing unique wave transport phenomena through interface or edge modes that are impurity-immune and potentially unidirectional. In mechanics, these phenomena arise by marrying the notion of material and structure, and are expected to lead to functionalities at the mesoscale that are unattainable solely based on the properties of constituents. Beyond the mere notion of a material, these meta-structures draw their unique characteristics from their finite size and the existence of interfaces. The resulting structural assemblies are expected to feature unprecedented performance in terms of stress wave mitigation, wave guiding, acoustic absorption, and vibration isolation. \u0000The seminar illustrates investigations on the effects of nonlinearities on topological properties, and the study of quasi-periodic assemblies. Investigation of the effects of nonlinearities on topological properties allows the exploration of the appearance/robustness of edge and localized modes in the presence of nonlinearities. In addition, the study of lattices with quasi-periodic configurations uncover additional unique properties related to vibration localization in one-dimensional and two-dimensional systems. These can be as interesting if not more useful than the interface modes that are found in periodic structures, as the quasi-periodicity framework provides a consistent methodology that leads to vibration confinement in systems that are not ordered, but are described by deterministic property distributions. Beam and plate structures with quasiperiodic arrangements of grounding springs and lumped masses are presented as structural components which support a variety of localized modes and that are suitable for the experimental characterization of the dynamic behavior of these configurations.","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125717055","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}
{"title":"Hoisting safety detection technology based on faster R-CNN (Conference Presentation)","authors":"Xuefeng Zhao, Yang Zhang, Zhen Yang, Mingyuan Zhang, Dongfang Li, Guangyi Zhou","doi":"10.1117/12.2515287","DOIUrl":"https://doi.org/10.1117/12.2515287","url":null,"abstract":"","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"260 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123468385","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 article presents a nondestructive evaluation (NDE) method to infer the axial stress in thick beams with the aim to extent the methodology to continuous welded rails. The method relies on the propagation of highly nonlinear solitary waves generated at one end of a chain of spherical particles in contact with the beam to be evaluated. The opposite end of the chain is in contact with the beam to be evaluated. Here the waves are reflected back to chain and the hypothesis is that the axial stress influences the amplitude and speed of the reflected waves. To verify this hypothesis a general finite element model of thermally stressed beams was developed and coupled to a discrete particle model able to predict the propagation of the waves along a L-shaped granular medium. The models were validated experimentally. The hypothesis was proven valid by both the numerical and the experimental results. In the future, these findings may be used to refine a NDE method to assess stress in columns, to infer the neutral temperature of continuous welded rails, and to prevent thermal buckling of critical structures.
{"title":"Measuring axial stress in thick structures using highly nonlinear solitary waves (Conference Presentation)","authors":"A. Nasrollahi, P. Rizzo","doi":"10.1117/12.2514059","DOIUrl":"https://doi.org/10.1117/12.2514059","url":null,"abstract":"This article presents a nondestructive evaluation (NDE) method to infer the axial stress in thick beams with the aim to extent the methodology to continuous welded rails. The method relies on the propagation of highly nonlinear solitary waves generated at one end of a chain of spherical particles in contact with the beam to be evaluated. The opposite end of the chain is in contact with the beam to be evaluated. Here the waves are reflected back to chain and the hypothesis is that the axial stress influences the amplitude and speed of the reflected waves. To verify this hypothesis a general finite element model of thermally stressed beams was developed and coupled to a discrete particle model able to predict the propagation of the waves along a L-shaped granular medium. The models were validated experimentally. The hypothesis was proven valid by both the numerical and the experimental results. In the future, these findings may be used to refine a NDE method to assess stress in columns, to infer the neutral temperature of continuous welded rails, and to prevent thermal buckling of critical structures.","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"62 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120994218","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}
S. Patra, Mohammad Sadegh Sadatzi, Sourav Banerjee, Hossain Ahmed
{"title":"Evidence of reduced order nonlinear state of Lamb wave due to stress-relaxation in composites (Conference Presentation)","authors":"S. Patra, Mohammad Sadegh Sadatzi, Sourav Banerjee, Hossain Ahmed","doi":"10.1117/12.2514485","DOIUrl":"https://doi.org/10.1117/12.2514485","url":null,"abstract":"","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116750470","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}
While most of the conventional acoustic liner which comprised of a micro-perforated panel (MPP) backed by a honeycomb structure shows good acoustic performance at high or medium frequency range, there is still very challenging for them at low-frequency range. Difference from MPP where resonance frequency of a MPP based liner is much depended on the backing space and shifting the absorption peak of the liner to low-frequency range generally makes the structure bulky and down-grades the absorbing quality, Helmholtz resonators shows easy frequency-tuning ability and outstanding absorption at low-frequency. In this research, by carefully design, the proposed designs of acoustic liner based on multiple Helmholtz resonators (MHR) show very good absorption in a broadband at low-frequency. First, a super unit-cell which is an annulus disk comprised of three segments or Helmholtz resonators is numerically studied to tune the working frequency band into the desired region, to form a broadband working region and to have the supercells absorbing potential. Afterward, the proposed liner constructed by patterning the supercells along the central axis of the liner is studied on absorption by using both commercial code (COMSOL) and theoretical analysis. The results show high absorption (>80%) at low-frequency broadband (400Hz to 650Hz) and good agreement between numerical and theoretical analysis. The proposed design and analysis can be served as effective model and tool for design and constructing advanced acoustic liners.
{"title":"Multiple Helmholtz resonator based acoustic liner (Conference Presentation)","authors":"H. Nguyen, Guoliang Huang","doi":"10.1117/12.2514364","DOIUrl":"https://doi.org/10.1117/12.2514364","url":null,"abstract":"While most of the conventional acoustic liner which comprised of a micro-perforated panel (MPP) backed by a honeycomb structure shows good acoustic performance at high or medium frequency range, there is still very challenging for them at low-frequency range. Difference from MPP where resonance frequency of a MPP based liner is much depended on the backing space and shifting the absorption peak of the liner to low-frequency range generally makes the structure bulky and down-grades the absorbing quality, Helmholtz resonators shows easy frequency-tuning ability and outstanding absorption at low-frequency. In this research, by carefully design, the proposed designs of acoustic liner based on multiple Helmholtz resonators (MHR) show very good absorption in a broadband at low-frequency. First, a super unit-cell which is an annulus disk comprised of three segments or Helmholtz resonators is numerically studied to tune the working frequency band into the desired region, to form a broadband working region and to have the supercells absorbing potential. Afterward, the proposed liner constructed by patterning the supercells along the central axis of the liner is studied on absorption by using both commercial code (COMSOL) and theoretical analysis. The results show high absorption (>80%) at low-frequency broadband (400Hz to 650Hz) and good agreement between numerical and theoretical analysis. The proposed design and analysis can be served as effective model and tool for design and constructing advanced acoustic liners.","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115845480","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}
Floquet Topological Insulators (FTIs) have inspired analogues in photonics, optics, and acoustics, in which non-reciprocal wave propagation in topologically protected materials, with topological immunity against structural defects and disorder, is achieved due to the breaking of time-reversal symmetry induced by time-modulation. This study aims at investigating a possibility for the existence of a mechanical analogue to the Quantum Hall Effect (QHE) in one and two-dimensional periodically modulated lattices. In 1D, the system shows topologically protected one-way edge modes as the time-modulation is turned on, which is demonstrated by the principle of bulk-edge correspondence and transient numerical simulations. The study is then extended to 2D hexagonal lattices to demonstrate the existence of Floquet topological edge modes. The band diagram and helical edge states characteristic of QHE are obtained by using the Plane Wave Expansion (PWE) method. Given the breakage of the time-reversal symmetry, the system switches from the trivial state to the nontrivial topological one that is quantified in terms of topological invariant Chern numbers. Last, the robustness of one-way edge modes and their immunity to backscattering by sharp corners, defects and modulation disorders are analyzed and assessed numerically.
{"title":"Elastic waves in Floquet topological insulators (Conference Presentation)","authors":"Hui Chen, H. Nassar, Guoliang Huang","doi":"10.1117/12.2514367","DOIUrl":"https://doi.org/10.1117/12.2514367","url":null,"abstract":"Floquet Topological Insulators (FTIs) have inspired analogues in photonics, optics, and acoustics, in which non-reciprocal wave propagation in topologically protected materials, with topological immunity against structural defects and disorder, is achieved due to the breaking of time-reversal symmetry induced by time-modulation. This study aims at investigating a possibility for the existence of a mechanical analogue to the Quantum Hall Effect (QHE) in one and two-dimensional periodically modulated lattices. In 1D, the system shows topologically protected one-way edge modes as the time-modulation is turned on, which is demonstrated by the principle of bulk-edge correspondence and transient numerical simulations. The study is then extended to 2D hexagonal lattices to demonstrate the existence of Floquet topological edge modes. The band diagram and helical edge states characteristic of QHE are obtained by using the Plane Wave Expansion (PWE) method. Given the breakage of the time-reversal symmetry, the system switches from the trivial state to the nontrivial topological one that is quantified in terms of topological invariant Chern numbers. Last, the robustness of one-way edge modes and their immunity to backscattering by sharp corners, defects and modulation disorders are analyzed and assessed numerically.","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130904193","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}
{"title":"Experimental validation of acoustic valley Hall edge states in a nonresonant topological elastic waveguide (Conference Presentation)","authors":"Ting-Wei Liu, F. Semperlotti","doi":"10.1117/12.2514328","DOIUrl":"https://doi.org/10.1117/12.2514328","url":null,"abstract":"","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"147 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122917060","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}
{"title":"Damage detection capabilities of strain-based displacement methods in beam-like structures (Conference Presentation)","authors":"K. Kliewer, B. Glisic","doi":"10.1117/12.2515385","DOIUrl":"https://doi.org/10.1117/12.2515385","url":null,"abstract":"","PeriodicalId":359388,"journal":{"name":"Health Monitoring of Structural and Biological Systems XIII","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127916156","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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