Abstract: A method for host vibration test is disclosed in the present invention. The method includes outputting an initial power spectrum density to a testing platform by a data acquisition device so as to vibrate the testing platform according to the initial power spectrum density. A host is disposed on a supporter, and the supporter is set on the testing platform. The method further includes installing a first accelerometer on the supporter, generating a first power spectrum density according to data detected by the first accelerometer, installing a second accelerometer on the testing platform, generating a second power spectrum density according to data detected by the second accelerometer, and the data acquisition device executing the vibration test of a host according to the first power spectrum density and the second power spectrum density.

Abstract: A method for detecting blockage of a measuring tube of a Coriolis flow measuring device, which has at least two measuring tubes. For this, the at least two measuring tubes are excited by at least one exciter to execute mechanical oscillations, mechanical oscillations of the measuring tubes are registered by at least one sensor and at least one measurement signal representing the mechanical oscillations is produced. At least one produced measurement signal is analyzed for the occurrence of a deviation of a resonance frequency of one measuring tube relative to a resonance frequency of the at least one other measuring tube. In case such a deviation occurs, blockage of a measuring tube is established.

Abstract: The invention is directed to a method for monitoring vibrations to detect distinct vibration events in an acceleration waveform converted into acceleration samples. The method comprises: storing the acceleration samples as a sequence of acceleration frames into a cache memory (S110); detecting the presence or absence of a distinct vibration event in each of said acceleration frames (S160); in case of detecting a distinct vibration event in an acceleration frame, forwarding said acceleration frame from said cache memory to a long-term storage device (S170).

Abstract: Method of operating an apparatus for analyzing the condition of a machine part rotating with a speed of rotation, includes: receiving a first digital signal dependent on mechanical vibrations emanating from the rotating part; analyzing the first digital signal to detect peak amplitude values during a finite time period corresponding to a predetermined amount of revolution of the rotatable part; the predetermined amount of revolution corresponding to at least one revolution of the monitored rotatable part; defining a plurality of amplitude ranges, each amplitude range corresponding to a peak occurrence frequency of more than one peak per revolution; sorting the detected peak amplitude values into corresponding amplitude ranges to reflect occurrence of detected peak amplitude values within the plurality of amplitude ranges; establishing a peak amplitude value for detected peaks having an occurrence frequency of about NL peaks per revolution, the occurrence frequency NL being a number higher than one.

Abstract: Disclosed herein is a method of reconstructing a sound field. The method comprises receiving measured values indicative of a first acoustic quantity measured at a set of measurement locations; defining a set of virtual source locations; and computing a second acoustic quantity for at least one target location from one or more wave functions each representative of a respective sound field originating from a respective one of the defined set of virtual source locations; wherein the one or more wave functions are weighted by respective one or more weighting factors, and wherein computing comprises determining the one or more weighting factors from a least-norm fit of the one or more wave functions to the received measured values.

Abstract: An ultrasonic measuring method includes: (A) receiving a coded spread spectrum ultrasonic signal in at least two receivers, and generating at least two received signals; (B) performing an quadrature detection on the received signals using the carrier frequency, and producing I and Q components of the received signals; (C) performing phase difference processing on the I and Q components with a coding period synchronized with that of the carrier frequency, and obtaining I? and Q? components from which a phase shift caused by a Doppler shift has been canceled; (D) despreading the I? and Q? components signals using different codes at time intervals synchronized with the carrier frequency, and obtaining despread I? and Q? components; (E) computing the amplitude and phase information based on the I? and Q? components; and (F) calculating the propagation distance and/or orientation of the ultrasonic wave based on the amplitude and phase information.

Abstract: A method (200) for the characterization of vibrational and/or acoustic transfer path related data of a physical system (100) where vibration or acoustics may play a role. The method (200) has a step of receiving (210) input data for at least one input point of the physical system and/or response data for at least one response point of the physical system (100). The method (200) further has a step of receiving (220) at least one system response function between the at least one input point and the at least one response point indicative of the transfer of vibration and/or acoustic signals. The method (200) also has a step of applying (230) at least one parametric model characterising at least one load on the physical system as a function of the input data, where the parametric models are identified from the input data and/or response data and the physical system response functions.

Abstract: A signal processing method for a Coriolis flowmeter including: performing frequency conversion to combine an oscillation frequency to each of two flow rate signals obtained by A/D conversion on input signals of the phase difference and/or the vibration frequency proportional to the Coriolis force acting on the at least one flow tube; measuring a frequency of a composite waveform associated with at least one of the vibration detection sensors; transmitting a control signal based on the measured frequency; controlling so that a sum frequency component or a difference frequency component of a composite component of a composite frequency signal is constant; and measuring phases from a sum signal or a difference signal of each of controlled converted composite frequencies, to thereby obtain a phase difference signal component.

Abstract: A disk drive tester is disclosed operable to test a plurality of disk drives, each disk drive comprising a head actuated over a disk. The disk drive tester comprises a plurality of test slots, where each test slot is operable to receive one of the disk drives. The disk drive tester further comprises an interface for receiving vibration data from the disk drives, wherein the vibration data at least partially represents a vibration applied to each disk drive by the respective test slot. The disk drive tester further comprises control circuitry operable to detect when one of the test slots is defective in response to the vibration data.

Abstract: Embodiments of the present general inventive concept provide a voice controlled vibration data analyzer system, including a vibration sensor to detect vibration data from a machine-under-test, a data acquisition unit to receive the vibration data from the vibration sensor, and a control unit having a user interface to receive manual and audio input from a user, and to communicate information relating to the machine-under-test, the control unit executing commands in response to the manual or audio input to control the data acquisition unit and/or user interface to output an audio or visual message relating to a navigation path of multiple machines to be tested, to collect and process the vibration data, and to receive manual or audio physical observations from the user to characterize collected vibration data.

Abstract: An apparatus is provided that includes a wave generator, plurality of transducers and processing device. The wave generator may be configured to simultaneously generate a plurality of acoustic waves that propagate through a laminate along a plurality of in-plane directions. The transducers may be spaced apart from one another and positionable at one or more known distances from the wave generator along respective in-plane directions. The transducers may be configured to detect acoustic waves propagating through the laminate along the respective in-plane directions. The processing device may be coupled to the transducers and configured to simultaneously calculate a plurality of elastic constants of the laminate as a function of velocities of the acoustic waves detected by the transducers. And the processing device may be configured to calculate the velocities as a function of the known distance(s) and arrival times of the acoustic waves at the transducers.

Abstract: A defect detection system and method enable a fastened crystalline silicon product to generate micro-vibration by a micro-vibration excitation device, so as to enable the crystalline silicon product to generate an excitation signal, then to acquire the excitation signal by a acquisition device, so as to analyze the excitation signal acquired by the acquisition device in the time and frequency domain by an analysis detection device with a specific analysis, and to obtain an analysis result, at last, determine a defect state of the crystalline silicon product according to the analysis result.

Abstract: To well remove a noise component due to vibration of a flexible member from an original detection signal output from a detecting unit and suppress a phase delay of a detection signal obtained by filtering. For this purpose, the present invention provides a detecting unit including a flexible member deforming according to a state of an object to be measured and a sensor detecting an amount of deformation of the flexible member and outputting an original detection signal indicating a detection result. A filtering unit outputs a detection signal obtained by filtering the original detection signal using a filter coefficient. A calculating device calculates a vibration frequency of the flexible member contained in the original detection signal. A changing unit changes a filter coefficient of the filtering unit to cause the filtering unit to function as a filter for attenuating the vibration frequency calculated by the calculating device.

Abstract: A vibration suppressing device includes a memory unit storing a stable rotation speed calculated by an arithmetical unit in association with a rotation speed range that includes the stable rotation speed, in which, when a command rotation speed that is a rotation speed of a rotary shaft is inputted in starting machining operation by rotation of the rotary shaft and, the arithmetical unit determines whether the command rotation speed is included in the rotation speed range or not, reads out the stable rotation speed when the command rotation speed is included in the rotation speed range and outputs the stable rotation speed to an NC device instead of the command rotation speed, and starts the machining operation at the stable rotation speed.

Abstract: A system and a method for enabling ultrasonic inspection of multiple or varying radii of a composite part without making mechanical adjustments to compensate for changes in the radius dimension. The system may comprise one or more ultrasonic pulser/receivers, one or more ultrasonic transducer arrays, a probe body or shoe to hold and position the array(s), ultrasonic data acquisition application software to drive the array(s), and ultrasonic data acquisition application software to select the best signal response for each column of pixels to be displayed. The inspection methodology enables the examination of smooth curved fillets which change shape along the length of the part.

Abstract: A method for determining the precision of gears includes steps of providing a gear pair; performing a single flank test for the gear pair, to generate a testing signal graph; decomposing the testing signal graph into a plurality of intrinsic-mode-function graphs; selecting a first function graph and a second function graph from the intrinsic-mode-function graphs; measuring the amplitude of vibration of the first function graph, to get a profile error of gear; combining the first and second function graphs to form a graph of function combination; calculating an adjacent pitch error and an accumulated pitch error by means of the graph of function combination; and defining the gear precision for one of the gear pair according to the profile error of gear, the adjacent pitch error and the accumulated pitch error.

Abstract: The safety valve vibration analyzer includes: a set condition input unit in which set conditions of a physical model including a safety valve and an upstream pipe connected to the safety valve are inputted; a safety valve governing equation holder that holds a safety valve governing equations; a pipe governing equation holder that holds a pipe governing equation; a processing unit that derives a time variation of a valve lift by using the set conditions inputted, the safety valve governing equations, and the pipe governing equations; and a valve lifting force function holder that holds a valve lifting force function. The processing unit derives the time variation of the valve lift by applying the valve lifting force function to the equation of motion of the valve disc.

Abstract: A method and a system for identifying failures in an aeroengine. The system includes: a mechanism defining a set of standardized indicators representative of operation of the aeroengine; a mechanism constructing an anomaly vector representative of a behavior of the engine as a function of the set of standardized indicators; a mechanism selecting in an event of an anomaly being revealed by the anomaly vector a subset of reference vectors having directions belonging to a determined neighborhood of a direction of the anomaly vector, the subset of reference vectors being selected from a set of reference vectors associated with failures of the aeroengine and determined using criteria established by experts; and a mechanism identifying failures associated with the subset of reference vectors.

Abstract: A data acquisition system for vibration analysis signals includes a logarithmic amplifier for compressing wide dynamic range signals. The logarithmic amplifier replaces attenuators, gain amplifiers, and gain switches used in a conventional system. Further, only a low bit-count analog to digital converter is needed in combination with the logarithmic amplifier. Consequently, the footprint of the system and system cost are reduced.

Abstract: Method for determining a characteristic for the quality of alignment of a rotating machine, by obtaining vibration data with at least one vibration sensor, and using the vibration data obtained with the vibration sensor to determine a characteristic for the quality of alignment. Furthermore, alignment data obtained from first and second optoelectronic units is used in addition to the vibration data obtained with the at least one vibration sensor to produce a combination value from which both an instantaneous vibration state and success of the alignment can be determined.

Abstract: A vibration data collection system performs an integration or differentiation process on incoming digitized vibration data in real time. The system uses a digital Infinite Impulse Response (IIR) filter running at the input data rate to provide the integration or differentiation function. With this approach, the system reduces hardware complexity and data storage requirements. Also, the system provides the ability to directly integrate or differentiate stored time waveforms without resorting to FFT processing methods.

Abstract: The invention provides a system for leak detection of a fluid in a pipe network. The system includes flow meters, and vibration detectors adapted to be attached to a pipe at a location in the pipe network. A processor analyzes signals generated by the flow meters and vibration detectors to identify the presence of one or more leaks in the pipe network. The invention also provides a method for detecting and localizing leaks in a pipeline network, and a device comprising a flow meter integral with a vibration detector for use in the system of the invention.

Abstract: Systems and methods for protecting rotating machines are provided. Measurements data collected by a plurality of sensors may be received by a controller that includes one or more computers. The plurality of sensors may be configured to monitor vibrations associated with the rotating machine. Based at least in part upon the measurements data, the controller may determine that a respective amplitude change for at least two of the plurality of sensors exceeds a threshold condition. The controller may also determine that the threshold condition is exceeded for a predetermined period of time. Based at least in part upon determining that the threshold condition is exceeded for a predetermined period of time, the controller may identify an alarm event.

Abstract: In the method of these teachings for detection of physical phenomena from or analysis of physical signals, an improved Empirical Mode Decomposition method decomposes physical signals representative of a physical phenomenon into components.

Abstract: Methods and systems are described for the identification and determination of loads by inverse analysis. A new combination of instrumentation and measurements is provided which allows accurate identification/measurement of static and/or dynamic forces, or loads, working on arbitrary test-objects or systems (i.e. test objects), through measurements of the results of the loads on the test object, signals like pressures, electrical potential, magnet flux displacement, strain, etc. This procedure allows the measurement/identification of arbitrary single or multiple loads, in arbitrary combinations, and multiple directions. The procedure also allows the measurement/identification of loads with arbitrary evolution in time, including static and dynamic loads.

Abstract: A structural optimization engine generates a response profile based on a vibrational analysis of a three-dimensional (3D) structure. The structural optimization engine determines whether the 3D structure complies with one or more design goals set for the 3D structure based on the response profile. When the 3D structure does not comply with the design goals, the structural optimization engine retrieves dependency data from a structure database. The dependency data indicates various dependencies between response characteristics included in the response profile and specific regions of the 3D model. Based on the dependency data, the structural optimization engine determines structural modifications that can be made to the 3D structure to bring the 3D structure into compliance with the design goals. A multi-axis computer-aided manufacturing unit then makes the structural modifications to the 3D structure.

Abstract: A fault detection and diagnosis method for a gas turbine engines comprises collecting a sensor signal from an acoustic or vibrational sensor at the gas turbine engine, pre-processing the sensor signal to remove predictable background, and extracting a feature set from the sensor signal using Mel-Frequency Cepstral Coefficients (MFCC) algorithms and/or Code Excited Linear Prediction (CELP) algorithms. Fault and non-fault states are reported based on comparison between the feature set and a library of fault and non-fault feature profiles corresponding to fault and non-fault states of the gas turbine engine.

Abstract: An electrodynamic machine shaft slow roll measurement testing and remediation method that can be performed on a partially machined shaft. Upon completion of slow roll tests on a partially machined shaft the manufacturer may complete machining of shafts that successfully meet the test specification. If a partially machined shaft fails the test specification, the manufacturer at its option may attempt to remediate the shaft, so that it successfully meets slow roll specification upon re-testing. Exemplary remediation steps may include further concentricity machining to reduce mechanical runout or shaft treatment, such as by heating and/or quenching to reduce electrical runout. Partially machined shafts that fail slow roll test specifications (with or without remediation efforts) may be scrapped or otherwise recycled without, completing final machining operations.

Abstract: Described are techniques for selecting options used with current sensor data characterizing vibration caused by rotating blades. Sets of other sensor data are evaluated to determine a first of the sets of other sensor data that is a best match for said current sensor data. Each of the sets of other sensor data is associated with one of a plurality of option sets. Each option set includes options used in determining one or more adjustments that may be applied to the blades to reduce vibration. The one or more sets of other sensor data are evaluated to determine a first of the sets of other sensor data that is a best match for said current sensor data. A first of the plurality of option sets associated with said first set of sensor data is used in determining adjustment(s) that may be applied to the blades.

Abstract: A method is presented for imaging an object. The method comprises imaging a coherent speckle pattern propagating from an object, using an imaging system being focused on a plane displaced from the object.

Abstract: According to a method by a frequency analysis of tap tones at the time when a tightness of a ripple member fixed by an elastic force has been tapped by a hammer or a method of detecting a response at the time when the ripple member has been vibrated, an enough precision cannot be obtained for a tightness estimation. A tapping force is applied to a plurality of positions on the member surface, thereby allowing a plurality of tap tones to be generated. Feature amounts are obtained from the plurality of tap tones. An average feature amount is obtained by averaging the feature amounts. The tightness of the ripple member is estimated from the average feature amount by using a correlation between the tightness of the ripple member and the average feature amount.

Abstract: A method and apparatus for monitoring a structure using an optical fiber based distributed acoustic sensor (DAS) extending along the length of the structure. The DAS is able to resolve a separate acoustic signal with a spatial resolution of 1 m along the length of the fibre, and hence is able to operate with an acoustic positioning system to determine the position of the riser with the same spatial resolution. In addition, the fiber can at the same time also detect much lower frequency mechanical vibrations in the riser, for example such as resonant mode vibrations induced by movement in the surrounding medium. By using vibration detection in combination with acoustic positioning then overall structure shape monitoring can be undertaken, which is useful for vortex induced vibration (VIV) visualisation, fatigue analysis, and a variety of other advanced purposes. The structure may be a sub-sea riser.

Abstract: A dynamic characteristic calculation apparatus for a machine tool calculates dynamic characteristic of the machine tool executing an interrupted machining by moving a rotational tool relative to a workpiece. The apparatus includes a detector detecting acoustic wave generated by vibration of the rotational tool or detecting magnetic property being variable by the vibration of the rotational tool where said rotational tool is excited to vibrate, and a calculation division calculating a natural frequency f of the one or plural tool tips in a vibration system, in which the one or plural tool tips of said rotational tool is a vibration body, on a basis of a value detected by the detector.

Abstract: A disclosed airfoil health monitoring system and method obtains a signal comprising a waveform indicative of an airfoil path with a sensor. Features of the waveform are determined and compared waveform characteristics indicative of a vibrational mode. A vibrational mode of the airfoil may then be determined based on the comparison between the predetermined waveform characteristics and the obtained waveform indicative of the airfoil path.

Abstract: A machine implement includes sensors that measure a force imparted by the machine implement to a structure during a machining process. A sensor array coupled to the structure measures the vibrational response of the structure to the imparted force. Analysis software compares the imparted force to the vibrational response to generate a transfer function for the structure. Based on the transfer function, a tool-path of the machine implement may be adjusted such that the resulting structure has precise vibrational characteristics that substantially comply with a set of design goals for the structure.

Abstract: Disclosed are systems, methods and articles, including an inspection system that includes at least one generator to apply energy to an object at an application point to cause waves to travel, at least partly, through the object. The system further includes at least one detector configured to detect at least a portion of the waves traveling through the object, and a statistical analyzer to perform a statistical analysis based on an output produced by the at least one detector in response to the detected portion of the waves, the statistical analysis being used to determine whether at least one defect is present in the object.

Abstract: A method includes transmitting a measurement-cycle ultrasonic signal from a signal transmitter toward a monitored space. Signals are received at a signal receiver. The signals include a sequence of measurement-cycle echo signals based on the transmitted measurement-cycle ultrasonic signal. Each measurement-cycle echo signal has associated signal strength. The method includes integrating data corresponding to the associated signal strengths for at least a portion of the sequence of measurement-cycle echo signals over time to produce an integrated measurement-cycle echo signal value. The method also includes comparing the integrated measurement-cycle echo signal value to an integrated calibration-cycle echo signal value that corresponds to the monitored space being empty.

Abstract: Methods and apparatus to use vibration data to determine a condition of a process control device are disclosed. An example method includes collecting first vibration data from a first sensor operatively coupled to a process control device during a calibration. The example method further includes calculating an operating threshold of the process control device based on the first vibration data, and determining a condition of the process control device if second vibration data associated with the process control device collected after the calibration exceeds the operating threshold.

Abstract: Some embodiments of the present invention provide a system that generates a composite vibration profile in a frequency range for a computer system. First, a vibration spectrum in the frequency range is measured for a test computer system in each configuration in a set of configurations. Then, the composite vibration profile for the computer system is generated based on the measured vibration spectra.

Abstract: Methods and systems are provided for operating a resonance measuring system, including a Coriolis mass flow meter. The resonance measuring system includes an electrical actuating apparatus, an electromagnetic drive, and an oscillation element which interacts with a medium. The electrical actuating apparatus provides an electrical excitation signal that excites the electromagnetic drive. The electromagnetic drive excites the oscillation element to oscillation. A mathematical model of the resonance measuring system depicts the oscillation element and the parameters of the mathematical model are being identified excitation of the oscillation element. The identified parameters and quantities are used for operating the resonance measuring system.

Abstract: Provided is a signal processing apparatus including: an transducer that performs scanning over the interior of an object and acquires received waveform data of a plurality of scanlines; an intensity screening unit that outputs a high intensity position at which signal intensity calculated from the received waveform data is higher than a first predetermined value; a correlation calculation unit that calculates a correlation value in a constant-width division for received waveform data of a first scanline and of a second scanline having a predetermined correlation with the first scanline; a position extraction unit that extracts, as a candidate position of a singular region, a position which corresponds to a high intensity position and for which the correlation value is lower than a second predetermined value; and an image processor that performs signal processing of generating image data of the object on the basis of the received waveform data.

Abstract: A method of isolating a frequency in a rotating machine having at least one sensor includes receiving, from the at least one sensor, a sensor signal that includes at least one frequency, converting the sensor signal to a digital vibration signal, modifying the vibration signal to generate an envelope signal, synchronously oversampling the envelope signal to generate a synchronous envelope signal, and transforming the synchronous envelope signal into a frequency spectrum to isolate the frequency.

Abstract: A test bed for an electrical energy storage system for vehicles includes a test system for conducting electrical tests of the energy storage system, optionally at least one conditioning unit for the climate control of the energy storage system, at least one data collection and analysis system, and optionally at least one safety system. In order to be able to test energy storage systems in a manner approximating their use as closely as possible in that all real influences on the energy storage system, for example, a traction battery for electric or hybrid vehicles, can be simulated with the simultaneous interaction of thermal, electrical, and mechanical influencing factors without the need to conduct tests in a real-world environment, at least one actuator is additionally provided for the mechanical stimulation of the energy storage system.

Abstract: A system to measure the internal state of a bundle of tubes by injecting a signal into each tube of the bundle, receiving reflections from the tube due to anomalies within the tube, then analyzing the reflections to determine the type or characteristics about the anomalies. The analyzed information is stored in database to be used for statistical processing. Further, the device can be used in the performance of a cleaning process by conducting an initial assessment of the tubes in a bundle of tubes, comparing the stored data and estimating the number of cleaning cycles that will be required, and re-conducting the evaluation of the state of the tubes after every cleaning cycle or after every few cleaning cycles.

Abstract: A method and apparatus for measuring the vibration of rotating blades, such as turbines, compressors, fans, or pumps, including sensing the return signal from projected energy and/or field changes from a plurality of sensors mounted on the machine housing. One or more of the sensors has a narrow field of measurement and the data is processed to provide the referenced time of arrival of each blade, and therefore the blade tip deflection due to vibration. One or more of the sensors has a wide field of measurement, providing a time history of the approaching and receding blades, and the data is processed to provide frequency content and relative magnitudes of the active mode(s) of blade vibration. By combining the overall tip deflection magnitude with the relative magnitudes of the active modes, the total vibratory stress state of the blade can be determined.

Abstract: A computer-controlled robotic platform with a collapsible lifting arm that positions a non-destructive inspection (NDI) sensor for scanning inside tunnel regions of a composite structure such as an integrally stiffened wing box. The lifting arm of a modified scissor lift mechanism can be collapsed to a very low height to pass through narrow sections of the integrally stiffened wing box, and also extended by more than a factor of three to reach the maximum height of the wing box tunnels. The system performs a vertical position sensing and control process that uses inverse kinematics to enable position control using data from a standard rotational encoder on the motor to determine vertical position. The system produces simulated encoder pulses that represent unit vertical displacements of a distal portion of a modified scissor lift mechanism using a forward kinematics equation in which the rotation angle of a lead screw is an input variable.

Abstract: A serialized probe component for an optoacoustic device has a unique identifier associated therewith and includes, in an embodiment, an operative connection between a read-write memory and the optoacoustic device. Software adapted to generate and store logs in a read-write memory is executed on the optoacoustic device and stores logs concerning utilization of the serialized probe component on the read-write memory. A method for logging operational information concerning an optoacoustic device is further disclosed.

Abstract: Systems and methods for determining spatially dense dynamic properties of a structure are disclosed. In particular, spatially dense mode shapes are determined using acceleration records collected when one or several sensors are moving. The mobile sensor gathers vibration response data for the structure as the mobile sensor moves over the structure. The vibration response data is used to extract a fine grid of modal coordinates with a reduced number of sensors and without requiring mode shape expansion. The high spatially dense mode shapes can be included as part of accurate numerical models for the structure that can be used for a variety of purposes, such as damage detection, earthquake engineering, wind engineering, and other suitable purposes.

Abstract: A process of collecting and manipulating data to measure the gap between structural components of a piece of equipment or a system is disclosed and claimed. The technique uses ultrasonic zero degree longitudinal waveforms to measure the gap. The technique subtracts the average of two adjacent waveforms from the waveform being processed to remove data from reflections from the components to reveal the reflections generated by the gap.

Abstract: Objects in a cargo shipping container are detected by measuring vibration resonant frequency peaks of the container. The mass of an object on the floor of the container effects the vibration resonance of the container, enabling the object to be detected. A vibration source and a plurality of accelerometers are either attached to the steel structure of the container, or are disposed on a supporting structure, such as a cargo crane or lift, so that they contact the container. The vibration source causes the container to vibrate, and the accelerometers detect the vibration resonance of the container. A mismatch between a cargo manifest and an observed cargo, or detection of an object having relatively high mass, e.g., due to lead shielding, can justify a manual inspection. The process uses synchronous processing to achieve the sensitivity needed, is unobtrusive, and does not slow the flow of cargo through a facility.