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公开(公告)号：US20210223214A1
公开(公告)日：2021-07-22
申请号：US17046713
申请日：2019-11-06
Applicant: DALIAN UNIVERSITY OF TECHNOLOGY
Inventor： Chunxu QU , Tinghua YI , Hongnan LI
IPC: G01N29/46
Abstract: The presented invention belongs to the technical field of data analysis for engineering structural monitoring, and relates to a method of complex modal identification for the structure with proportional damping. Firstly, the set of single source points containing the real modal shapes are obtained by short time Fourier transform and single source point detection, and then the real modal shapes are calculated by hierarchical distance method. Then, the impulse response and its Hilbert transform are obtained by natural excitation technology and Hilbert transform, respectively. The relationship between modal response and impulse response with its Hilbert transform is established. Finally, the complex modal parameters are solved. In this invention, the procedures of hidden complex modes of structures with proportional damping are given by explicit expression, which reveal the structural dynamic characteristics essentially.
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公开(公告)号：US20200074221A1
公开(公告)日：2020-03-05
申请号：US16342948
申请日：2018-03-28
Applicant: Dalian University of Technology
Inventor： Tinghua YI , Xiaomei YANG , Chunxu QU , Hongnan LI
Abstract: Structural health monitoring relating to an automatic method for estimating structural modal parameters by clustering. The structural modal parameters from state-space models are calculated in different orders by Natural Excitation Technique in combination with Eigensystem Realization Algorithm According to the characteristics that physical modes are those with high similarity and stably appearing at different orders while spurious modes are those with little similarity and unstably appearing at different orders, the modal dissimilarity between two nearest modes in consecutive order are considered as feature of the mode in the lower order. Then, features of modes are used in fuzzy C-means clustering to adaptively acquire the stable cluster where modes are with high similarity. Finally, Hierarchical clustering is used to group the stable modes with identical modal parameters together and thus each physical mode can be obtained.
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公开(公告)号：US20190171691A1
公开(公告)日：2019-06-06
申请号：US16321183
申请日：2018-03-06
Applicant: Dalian University of Technology
Inventor： Chunxu QU , Tinghua YI , Hongnan LI
Abstract: The presented invention belongs to the technical field of data analysis for structural health monitoring, and relates to a method of the mode order determination for the modal identification of engineering structures. The presented invention first calculates the structural natural frequencies for every order by eigensystem realization algorithm. Then the modal responses for every natural frequency are extracted. After obtaining the square mean root of modal responses, the modal response contribution index (MRCI) is calculated by summation of square mean root for every degree-of-freedom. The relation map between mode order and MRCI is drawn. The mode order is determined by the obvious gap between two adjacent MRCI according to the relation map. This order is also the truncated order of singular matrix in the eigensystem realization algorithm, which is useful to identify other modal parameters accurately.
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公开(公告)号：US20200065438A1
公开(公告)日：2020-02-27
申请号：US16342929
申请日：2018-03-27
Applicant: Dalian University of Technology
Inventor： Tinghua YI , Xiaomei YANG , Chunxu QU , Hongnan LI
Abstract: Structural health monitoring relating to a real-time tracking method for structural modal parameters. The Natural Excitation Technique transforms structural random responses into free decaying responses used to calculate structural modal parameters by the Eigensystem Realization Algorithm combined with the stabilization diagram. Considering influence of environmental excitation level on the number of identified modes, the reference mode list is formed by union of modes obtained from response sets in a day. Then the modes can be tracked automatically according to rules of minimum frequency difference and maximum Modal Assurance Criterion (MAC). To avoid mode mismatch problem caused by absence of threshold, frequency differences and MACs between all modes from the latter response set and all reference modes are calculated and the mode will be tracked into the cluster corresponding to the specified reference mode only in the case that their frequency difference is smallest and the MAC is largest.
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Patent Agency Ranking
公开(公告)号：US20210350040A1
公开(公告)日：2021-11-11
申请号：US17052748
申请日：2020-03-06
Applicant: DALIAN UNIVERSITY OF TECHNOLOGY
Inventor： Tinghua YI , Mingsheng XUE , Chunxu QU , Hongnan LI
Abstract: The present invention belongs to the technical field of data analysis for structural testing, and relates to a method of the physical mode exaction for flexibility identification of engineering structures. In the present invention combined deterministic-stochastic subspace identification algorithm is first adopted to calculate basic modal parameters and modal scaling factors from state-space models of different orders. Subsequently, the relative scaling factor difference is added as a new modal indicator to the classic stabilization diagram to better clean out the stabilization diagram. And check the correctness of the selection of the stable axis using single-modal frequency-domain similarity index (SFSI) between single-order FRF and measured FRF. Then, further determine the physical modes from the modes in the stable axis using multi-modal frequency-domain similarity index (MFSI) between lower-order superposition FRF and measured FRF. Finally, calculate flexibility matrix using identified modal parameters and predict the displacement of the structure under static load.
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公开(公告)号：US20200033226A1
公开(公告)日：2020-01-30
申请号：US16342954
申请日：2018-03-12
Applicant: Dalian University of Technology
Inventor： Tinghua YI , Xiaomei YANG , Chunxu QU , Hongnan LI
IPC: G01M5/00
Abstract: Structural health monitoring relating to an automatic method for tracking structural modal parameters. First, Natural Excitation Technique is used to transform the random responses into correlation functions and Eigensystem Realization Algorithm combined with the stabilization diagram is used to estimate modal parameters from various response segments. Then, modes from the latter response segment are classified as traceable modes or untraceable modes according to correlations between their observability vectors and subspaces of the existing reference modes. Final, traceable modes will be grouped into specified clusters with the same structural characteristics on the basis of maximum modal observability vector correlation and minimum frequency difference. Meanwhile, union of the untraceable modes and existing reference modes are updated as the new reference modes which can be applied into the next tracking process. This can track the modal parameters automatically without artificial thresholds and the specified reference modes.
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7.发明申请公开(公告)号：US20200284687A1
公开(公告)日：2020-09-10
申请号：US16479730
申请日：2019-03-01
Applicant: Dalian University of Technology
Inventor： Tinghua YI , Xiaomei YANG , Chunxu QU , Hongnan LI
Abstract: A method for automatically detecting the free vibration response segment of the high-speed railway bridges after trains passing. First, pre-select the test response sequence to be decomposed based on the maximum of the time instants corresponding to the absolute maximums of the response vectors at various measuring point. Then, Extract the single-frequency modal response from the test response by the iterative variational mode decomposition and fit the envelope amplitude of the modal response by Hilbert transform. Finally, the vibration features at each time instants are marked as decay vibration or non-decay vibration. The longest structural response segment that meets the decay vibration features is determined as the detected free vibration response segment for modal identification. This invention can effectively detect the free vibration data segment without human participation, which is of great significance for the real-time accurate modal analysis of high-speed railway bridges.
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公开(公告)号：US20200089733A1
公开(公告)日：2020-03-19
申请号：US16342951
申请日：2018-06-04
Applicant: Dalian University of Technology
Inventor： Tinghua YI , Xueyang PEI , Chunxu QU , Hongnan LI
Abstract: Sensor placement for structural health monitoring and sensor placement method for reducing uncertainty of structural modal identification. Influences of structural model error and measurement noise on measured responses are separated. Structural stiffness variation is used as model error, and Gaussian noise is used as measurement noise. Monte Carlo method simulates a large number of possible cases, and structural mode shape matrices under each model error condition are obtained. Conditional information entropy index quantifies and calculates uncertainty of identified modal parameter results. Conditional information entropy index solves the problem of uncertain Fisher information matrix, which cannot be solved by traditional information entropy method. Optimal sensor placement corresponds to maximum conditional information entropy index value. The sensor placement method considers influences of structural model error and measurement noise on structural modal identification, which is helpful for improving accuracy of structural modal parameter identification.
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9.发明申请公开(公告)号：US20200089730A1
公开(公告)日：2020-03-19
申请号：US16342953
申请日：2018-08-27
Applicant: Dalian University of Technology
Inventor： Tinghua YI , Xiaojun YAO , Chunxu QU , Hongnan LI
Abstract: Data analysis for structural health monitoring relating to a method of modal identification for structures with non-proportional damping based on extended sparse component analysis. Hilbert transform constructs analytical signal of acceleration response. Analytical signal is transformed into time-frequency domain using short-time-Fourier transform. The criterion is taken as the correlation coefficient of adjacent frequency points is close to 1. Points contributed by only one mode are detected from the time-frequency plane. Phases calculated at single-source-points are used to remove local outliers through local outlier factor method. Amplitudes of complex-valued mode shapes are estimated by Hierarchical clustering of amplitudes for time-frequency coefficients at single-source-points. Averaged phases of grouped single-source-points are estimated phases of complex-valued mode shapes. Finally, complex-valued mode shapes are acquired. Modal responses are estimated by sparse reconstruction method. This method extends application range of sparse component analysis method, and can identify complex modes of non-proportionally damped structures.
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