A method to assess the integrity of a structure is provided and comprises the steps of: i) applying a sinusoidally varying force to the structure at a frequency or frequencies below the lowest frequency that could cause resonance in the structure whereby to set up a dynamic response dominated by the stiffness of the structure; and ii) monitoring the dynamic response of the structure. A device to assess the integrity of a structure is also provided.

A one-dimensional (1D) and two-dimensional (2D) scan scheme 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 tracks a rotating structure and sweep its laser spot on its surface. The measured response of the structure using the 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 operational modal analysis (OMA) methods (e.g., an improved lifting method, an improved demodulation method, an improved 2D demodulation method). 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.

A system for dynamically mitigating resonance in a transport refrigeration unit (TRU) during a mission, having: a TRU controller configured for operating a TRU engine during the mission according to an operational baseline, and while operating the TRU engine, contemporaneously performing steps including: obtaining a first set of data that comprises real time measurements from one or more accelerometers installed in the TRU; converting the real measurements to a second set of data that comprises real time shock and vibration data; processing the second set of data in a control loop to determine an updated operational baseline that avoids resonance detected in the first set of data; and operating the TRU engine according to the updated operational baseline.

A resonance detection system includes a vibration simulation mechanism and a vibration audio analysis device. The vibration simulation mechanism includes a mechanism body that accommodates a peripheral interface device, such as a notebook computer key input mechanical structure. The vibration simulation mechanism generates a vibration wave to the peripheral interface device generates a vibration audio signal in response to the vibration wave. The vibration simulation mechanism further includes a patch-type audio collector, such as a miniature auscultation radio patch, which is connected with the vibration audio analysis device. The patch-type audio collector is attached on the mechanism body containing the peripheral interface device. The vibration audio signal is collected by the patch-type audio collector. The vibration audio analysis device judges whether there is an abnormal resonance phenomenon in the vibration auto signal, which may be used for fabrication quality control of peripheral interface devices.

Certain embodiments may generally relate to structural damage detection. An embodiment may be directed to method for identifying a presence and a location of structural damage. Such method may include training a convolutional neural network (CNN) for a joint of a structure, sending instructions to a modal shaker to induce an input to the structure, receiving, as a result of the induced input, a raw acceleration signal at the joint, computing, based on the trained CNN and the raw acceleration signal, an index value of the joint, and identifying, according to the index value, a presence of a location of structural damage of the structure. In a further embodiment, the index value represents a likelihood of damage at the joint.

A method for non-contact modal analysis uses an optical sensing device such as a video camera. Unlike traditional modal analysis, requiring accelerometers or force sensors to measure the modal characteristics of a structure, the inventive system uses pixel displacement measurements from the optical sensor to characterize the modal properties of the device under test. The input or reference signal is measured by an independent data acquisition system and is synchronized with the response motion captured in video recordings.

A detection method of nonlinear ultrasonic guided wave with carrier modulation is described. The high and low frequency components are determined according to the frequency response characteristics of the detection object, and the high-frequency components are processed by delay and combined with the low-frequency components to form a carrier modulation signal. The single excitation and single receiving mode are adopted for signal acquisition. The carrier modulation signal with high frequency and low frequency components is excited by a single transducer. The nonlinear modulation effect is produced by the interaction between the carrier signal and the damage, and the signals are collected by the receiving transducer through transmission method. According to the arrival time of high frequency components and the time of end reflection echo, the signal is intercepted and analyzed. After filtering and normalization processing, the received signal is decomposed by empirical mode decomposition (EMD). According to the decomposed IMF spectrum information, IMF components including fundamental frequency and nonlinear frequency components are used for signal reconstruction. The difference frequency components generated by the modulation of high-frequency and low-frequency, namely nonlinear components, are extracted, and the non-linear coefficient is calculated. The damage degree of materials is evaluated based on the nonlinear coefficient of nondamaged state.

Relating to the technical field of batteries, and provided are a battery fault detection method, a battery fault detection system, a terminal, and a computer-readable storage medium. The method comprises: by means of a vibration generation device, sequentially applying a preset number of vibration signals of different frequencies to a battery to be tested (301); collecting response signals of the battery by means of a response collection device (302), the response signals comprising a preset number of vibration response amplitudes of the battery, wherein the preset number of vibration response amplitudes are separately generated by the battery under the action of vibration signals of different frequencies; and according to the response signals, determining whether the battery is faulty (303). By means of the described method, it is possible to quickly and non-destructively detect whether a battery is faulty.

Systems and methods for automated MIMO force-response characterization of a device/structure-under-test. A SIMO exciter router is operated to selectively couple an excitation signal input to an exciter device while the sensor data indicative of a sensed response to the imparted excitation force is collected from a plurality of response sensors. The SIMO exciter router operates to collect sensor data for each of a plurality of different exciter-sensor combinations (i.e., sensor data is collected from each individual response sensor while the excitation force is applied by each individual exciter device). The sensor data is collected by a data acquisition system with a plurality of signal input channels each coupled to a different response sensor or a sensor router is used to selectively couple each individual sensor output to a shared signal input channel of the data acquisition system.

A water leakage position estimation system (S) configured to estimate a water leakage position in a pipe network including a plurality of pipe routes includes a water leakage determination unit (11) estimation unit (12e) . The water leakage determination unit (11) determines whether a water leakage occurs in the pipe network based on a measured value of a vibration related to the pipe network that is acquired by a water leakage sensor (2) provided in the pipe network. The estimation unit (12e) estimates, when the water leakage determination unit (11) determines that a water leakage occurs in the pipe network, a pipe route in which the water leakage occurs from the plurality of pipe routes based on the measured value and a predicted value of the vibration for each pipe route acquirable by the water leakage sensor (2) when a water leakage occurs in each pipe route.