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.

Abstract: Structural health monitoring providing sparse component analysis method for structural modal identification with incomplete number of sensors.

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.

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.

Abstract: An eddy current energy-dissipating spacer is mainly composed of a spacer frame, a conductor clamp and energy-dissipating elements. The eddy current energy-dissipating spacer not only provides the function of an ordinary spacer, but also reduces the vibration of the transmission lines; and at the same time, can effectively reduce the vibration of the transmission lines, especially the torsional vibration by adopting the eddy current and viscoelastic material for energy dissipation; improves the eddy current strength by adjusting the gear radius ratio, thus increasing the damping force; can adjust the damping parameters by adjusting the magnetic field strength of the permanent magnet; can produce long-term stable vibration reduction effect by adopting the permanent magnet to provide continuous magnetic field without additional external energy input; can effectively avoid the magnetic flux leakage of magnetic circuits by adopting the magnetic material.

Abstract: A self-resetting tuned mass damper is based on eddy current and shape memory alloy technology. The self-resetting tuned mass damper comprises a hollow box, a cover plate, a bolt, a mass block, gears a, gears b, gears c, copper sheets, permanent magnet groups, partition boards, balls, pins, levers, shape memory alloys, rotating shafts a, rotating shafts b, a supporting plate and rotating shafts c. The movement of the mass block causes the copper sheets to rotate and generate eddy current for energy consumption. The copper sheets are rotated and amplified by adjusting the sizes of the gears. The displacement of a small mass block can cause rotation of the copper sheets by a large angle, which greatly increases energy consumption efficiency. The elongation of the shape memory alloys is amplified by adjusting the ratio of long and short force arms of the levers.

Abstract: The present invention discloses a coupling beam eddy current damper with shear displacement amplification. The coupling beam eddy current damper with shear displacement amplification comprises a rigid rod, rotating shafts, a pin column, pins, levers, screws, thread sleeves, copper sheets, permanent magnet components, a steel structural component, balls, ball supports and an outer shell. When vibration occurs, coupling beams on both sides of the damper are relatively vertically displaced; at this moment, two levers move up and down relative to the rigid rod; the movement causes the screws and the copper sheets to rotate; the copper sheets rotate in a magnetic field, then induced electromotive force will generates inside the magnetic field, thereby generating eddy current in the copper sheets. The eddy current effect will produce a damping force that impedes the rotation of the copper sheets.

Abstract: The present invention belongs to the technical field of health monitoring for civil structures, and a dynamically non-Gaussian anomaly identification method is proposed for structural monitoring data. First, define past and current observation vectors for the monitoring data and pre-whiten them; second, establish a statistical correlation model for the whitened past and current observation vectors to obtain dynamically whitened data; then, divide the dynamically whitened data into two parts, i.e., the system-related and system-unrelated parts, which are further modelled by the independent component analysis; finally, define two statistics and determine their corresponding control limits, respectively, it can be decided that there is anomaly in the monitoring data when each of the statistics exceeds its corresponding control limit.

Abstract: An axial displacement amplified eddy current damper is disclosed. The axial movement of a slide bar is converted into the rotation of copper sheets and generates eddy current for energy consumption. The copper sheets are rotated and amplified by adjusting the sizes of gears. The short displacement of the slide bar can cause a large angle rotation of the copper sheets, so that energy consumption efficiency is high. The damping parameter can be adjusted by adjusting the magnetic field strength of permanent magnets, the thickness of the copper sheets and the distance from the copper sheets to the permanent magnets. The permanent magnets are adopted to provide continuous magnetic field sources, without external energy, thereby generating long-term and stable vibration reduction effect.

Abstract: The present invention belongs to the technical field of health monitoring for civil structures, and a performance alarming method for bridge expansion joints based on temperature displacement relationship model is proposed. First, the canonically correlated temperature is proposed to maximize the correlation between bridge temperature field and expansion joint displacement; second, a temperature displacement relationship model for bridge expansion joints is established based on canonically correlated temperatures; then, a mean-value control chart is constructed to the error of temperature displacement relationship model; finally, reasonable control limits are determined for the mean-value control chart. A more accurate temperature displacement relationship model can be established based on canonically correlated temperatures, which is of important value to improve the performance alarming ability for expansion joint.

Abstract: An inertial mass amplification type tuned mass damper is disclosed. The inertial mass amplification type tuned mass damper comprises a hollow box, an H-shaped mass block, gears a, gears b, a rectangular frame, a steel ring, viscous dampers, a steel sheet, springs, rotating shafts and balls. In the present invention, an inertial damping force is amplified by adjusting the radius ratio of the gears a and the gears b; and damping parameters can be conveniently changed by adjusting the mass of the mass block, the spring stiffness and the like. The present invention has the advantages that the design mass is small, which can avoid the adverse effects of excessive additional gravity on the structure and improve the performance of the structure. The present invention has reasonable design and small occupied space, can save more use area for buildings and can greatly improve the utilization efficiency of the buildings.

Abstract: The present invention belongs to the technical field of health monitoring for civil structures, and an anomaly identification method considering spatial-temporal correlation is proposed for structural monitoring data. First, define current and past observation vectors for the monitoring data and pre-whiten them; second, establish a statistical correlation model for the pre-whitened current and past observation vectors to simultaneously consider the spatial-temporal correlation in the monitoring data; then, divide the model into two parts, i.e., the system-related and system-unrelated parts, and define two corresponding statistics; finally, determine the corresponding control limits of the statistics, and it can be decided that there is anomaly in the monitoring data when each of the statistics exceeds its corresponding control limit.

Abstract: A transmission line vibration reduction device based on an eddy current energy consumption technology is provided, which can effectively reduce the vibration in the direction perpendicular to a transmission line, that is, the vibration in the direction of the most unfavorable load of a transmission tower structure under normal conditions, and can effectively improve the bearing capacity of a line iron tower; can greatly improve the energy consumption efficiency by carrying out energy consumption using an eddy current technology and by adjusting the gear radius ratio, and can effectively reduce the vibration of the transmission line; can realize the adjustment of damping parameters by adjusting the magnetic field intensity of permanent magnets and the distance between a copper sheet and each permanent magnet; can generate a long-term stable vibration reduction effect by using the permanent magnets to provide continuous magnetic field sources without outside energy.

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.

Abstract: The present invention discloses a multi-dimensional eddy current tuned mass damper, which belongs to the technical field of structural vibration control.

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.

Abstract: The present application discloses a method for making a rubber blade. The method includes applying a first coating composition and a second coating composition in separate steps on at least a part of a surface of a polyurethane elastic substrate; and solidifying the first coating composition and the second coating composition by ultraviolet light irradiating to form a hardened layer on the surface of the polyurethane elastic substrate. The first coating composition includes an isocyanate-group-terminated polyisocyanate and a first solvent. The second coating composition includes a first monomer, a photoinitiator, and a second solvent. The first monomer is at least one of an acrylate monomer and a methacrylate monomer each having an reactive hydroxyl group. The isocyanate group of the polyisocyanate is reacted with the reactive hydroxyl group of the first monomer to generate a urethane group to form a polyurethane acrylate. The present application also discloses a rubber blade.

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.

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.

Abstract: Structural health monitoring providing sparse component analysis method for structural modal identification with incomplete number of sensors.