Abstract: Techniques for fluid measurement include the ability to introduce a vibration to a container wall and to detect the vibration after the vibration has propagated at least partially around the container wall. Based on the detection of the vibration, the techniques also include the ability to determine a fluid state.

Abstract: An acceleration sensor, installed together with an angular velocity sensor in the same casing, detects the acceleration induced by the external vibration. Its detection signal Vs is supplied to first and second band-pass filters to extract a driving system resonance frequency fd of the angular velocity sensor as well as a difference frequency ?f between the driving system frequency component and a sensing system resonance frequency. The extracted signals Vs1 and Vs2 of respective frequency components are supplied to first and second window comparators. When each frequency component deviates from a predetermined range, a diagnostic signal Vd notifying the abnormal condition of the angular velocity sensor is produced.

Abstract: The present invention is an apparatus for detecting machine parameters including vibration, producing signal corresponding to the parameters and conditioning the signals by means of predetermined criteria such as amplitude and time criteria. Routes may be input to the analyzer with settings that govern part of the conditioning for individual machines. The predetermined criteria also may include an input limit criterion which ensures the safety of the analyzer circuitry by indicating attenuation levels for incoming signals. The analyzer is also capable of two channel analysis of input signals including a summing analysis. The analyzer has thumb operated controls for easy operation in harsh environments.

Abstract: The invention proposes a method for detecting the motion of an element relative to a sensor device, in which signals (7 to 15) are evaluated as a function of a pulse generator (1) that is moved past the sensor (3, 4, 5). The signals (7, 8; 10, 11; 13, 14) of two sensor elements (4, 5) disposed next to each other in the movement direction are detected, wherein in order to detect vibrations perpendicular to the movement direction, the phase responses of the signals (7, 8; 10, 11; 13, 14) of the individual sensor elements (4, 5) and of the differential signals (9; 12; 15) of the individual sensor elements (4, 5) are evaluated as to whether all three signals are in phase.

Abstract: A method is provided to distinguish two blended but different waves in a structure, such as compressional and shear waves, by measuring their corresponding wavenumbers and wave speeds. Other characteristics of the two waves may also be measured such as the propagation coefficients of both waves. All measurements can be calculated at every frequency for which a transfer function measurement is made. The measurements do not depend on the resonance frequencies of the structure and do not require curve fitting to the transfer functions.

Abstract: Disclosed is a system and method for monitoring the vibration levels of gas turbine engines. The vibration monitoring system acquires vibration data from an engine, and processes the data with advanced algorithms to determine engine component health, both in a diagnostic and prognostic fashion. The method includes the steps of measuring an operating parameter and a corresponding set of vibration amplitudes for a plurality of rotating component during a period of operation and normalizing the set of measured vibration amplitudes based on established amplitude limits. The set of normalized amplitude data points are stored in parameter-based data blocks, which extend over a predetermined range of the operating parameter. For each data block, a time period remaining to reach the established amplitude limits is estimated based on changes in the normalized amplitude data points stored in the data blocks.

Abstract: A pulse width measuring device is disclosed that calculates the pulse width of a signal to be measured, based on a count value and a count clock signal. In the pulse width measuring device, the counter circuit has a plurality of bits that are divided into an exponent and a significand. The control unit of the pulse width measuring device includes: an exponent storing unit that stores an exponent setting value that represents the number of bits of the exponent of the counter circuit; and a decoder unit that generates a count value setting signal for rewriting the count value of the counter circuit, based on the exponent setting value stored in the exponent storing unit, when the count value overflows in the counter circuit, the decoder unit then outputting the count value setting signal to the counter circuit.

Abstract: In a method for reducing sensed physical variables generating a plurality of control commands are generated at a control rate as a function of the sensed physical variables. An estimate of a relationship between the sensed physical variables and the control commands is also is used in generating the plurality of control commands. The estimate of the relationship is updated based upon a response by the sensed physical variables to the control commands. The generation of the control commands involves a quadratic dependency on the estimate of the relationship and the quadratic dependency is updated based on the update to the estimate.

Abstract: Novel tracked orders (i.e., tracked orders that are not present in “healthy” machinery) are useful for locating bearing anomalies. Accordingly, a method for locating bearing anomalies in machinery is provided that includes receiving vibration measurements acquired from the machinery, analyzing the vibration measurements to identify novel tracked orders indicative of bearing anomalies, and ascertaining the location of a bearing anomaly by relating a novel tracked order thus-identified to one or more further tracked orders. Thus, the novel tracked order does not merely indicate the occurrence of a bearing anomaly, but, in combination with the one or more further tracked orders, allows the bearing anomaly to be traced to a particular position.

Abstract: A method and apparatus for detecting problems in a rotating machine is disclosed. The method and apparatus include creating a definition of the rotating machine using a plurality of templates that specify components and functional characteristics of the components. In addition, the method and apparatus include identifying a plurality of sensors configured to provide operational data related to the rotating machine and defining a plurality of problem rules including logical expressions by which machine faults are deduced from specified portions of the operational data. Further, the method and apparatus include performing an analysis of operation of the rotating machine, the analysis including acquiring actual operational data from the plurality of sensors and applying the problem rules and templates to the operational data to detect faults in the rotating machine and in response thereto generating an indication when a fault is detected.

Abstract: A signal isolation system includes an aeroisolator to couple output signals to an electronic device. The aeroisolator is made from two commercial miniature earphones, each having a ferro-magnetic diaphragm activated by a voice coil in proximity to a permanent magnet. The diaphragm is removed from one of the earphones, and the two earphones are then disposed in proximity to each other, with the diaphragm in proximity to the voice coil of each.

Abstract: Tracking vibrations on a pipeline network includes installing multiple vibration recorders on the pipeline network, with each recorder including a sensor, a timer, a processor, and a digital communication device. At each vibration recorder, vibration signals are received from the sensor at programmed times under the control of the processor of the vibration recorders and processed by the processor. The processed vibration signals are communicated from the vibration recorder to a reader device using the digital communication device. Thereafter, the processed vibration signals from the one or more reader devices are collected at a central computer system. Finally, the collected processed vibrations signals are analyzed at the central computer system to determine abnormal vibration patterns and to obtain measures of any leaks present in the pipeline network.

Abstract: Determining a shaft balance adjustment includes measuring an initial vibration of the shaft, determining if the initial vibration is greater than a predetermined value, and, if the initial vibration is greater than the predetermined value, determining an adjustment by choosing a best adjustment for each possible location for adjustments. Choosing the best adjustment may include choosing an adjustment that causes a lower amount of vibration than adjustments not chosen. Measuring an initial vibration may include using an accelerometer. Measuring an initial vibration may include using conditioning electronics in connection with the accelerometer. The predetermined value may be 0.01 ips.

Abstract: A system and method for assessing and potentially correcting for non-translational motion in a resonance measurement apparatus is provided. The design measures the response of an article, such as an HGA assembly including a read/write head, as well as the excitation of a shaking device, such as a head resonance tester, and computes a correction factor using either two or three point measurement. The correction factor may be evaluated by subjecting the arrangement to further vibration at varying frequencies. Measurement of the shaking device may be accomplished using an accelerometer or by optical measurement using a light beam.

Abstract: Methods and apparatus for analyzing flutter test data using damped sine curve fitting. In one embodiment, a plurality of data points are read, with each data point representing an amplitude versus a test time. A number “N” of damped sine waves to fit to the plurality of data points is determined, and the number “N” of damped sine waves is fit to the plurality of data points using a non-linear “N” damped sine wave fitting algorithm.

Abstract: A method of estimating a pure spectrum and a concentration of each component constituting n sample mixtures, in which p kinds of components are mixed, includes (a) performing a principal component analysis of the spectra of the n mixtures, which are measured using m wavelengths, to represent the spectra of the n mixtures as factors and scores of the respective factors, wherein n, p, and m are integers and m>p, and (b) performing an independent component analysis of the scores obtained in (a) to estimate the pure spectra and the concentrations of the respective components.

Abstract: A method for monitoring the health of a system comprises performing at each of a plurality of times the steps of: constructing a condition signature from a plurality of condition indicators including (a) a plurality of vibration measurements acquired from the system or (b) one or more vibration measurements and one or more performance parameter measurements acquired from the system; predicting a normal signature from a model defining one or more inter-dependencies between said condition indicators, the normal signature corresponding to the condition signature for a healthy system; comparing the condition signature with the normal signature; and registering an event if the condition signature differs from the normal signature by more than a predetermined threshold.

Abstract: A contact sensitive device includes a member capable of supporting bending waves, a first sensor mounted on the member for measuring bending wave vibration in the member, the sensor determining a first measured bending wave signal, a second sensor to determine a second measured bending wave signal and a processor that optimizes a product of a set of corrected impulse response measurements from each sensor to determine information related to a contact.

Abstract: A method and device for detection of a pulsed mechanical effect on a plant component includes continuously recording an operating noise in the plant component with a sensor disposed on the plant component and converting the recorded noise into a measured signal with the sensor. Then, the measured signal is subjected to a Fourier transformation. An evaluation function is derived from a number of value spectra determined in the above manner, which gives the onset of a pulsed mechanical effect on the plant component.

Abstract: A method and related system for measuring rotor unbalance comprises rotating a rotor about an axis at a range of rotating speeds; generating a reference signal indicative of the instantaneous rotational frequency of the rotor; detecting the vibration of the rotor while the rotator is rotating, and generating a vibration signal; filtering the vibration signal, using the reference signal, to provide a synchronous vibration signal having a frequency equal to the instantaneous rotational frequency of the rotor; recording a vibration vector, the vibration vector comprising amplitude and phase values for the synchronous vibration signal; and measuring rotor unbalance based upon the vibration vector. Measurement accuracy can be improved by recording vibration vectors for a plurality of rotations of the rotor, and determining an average vibration vector. Methods and systems for detecting a rotor anomaly are also disclosed.

Abstract: A system is disclosed for use in assembling a plurality of rotatable elements in the assembly of a turbine engine. The system includes an initialization unit, a measurement unit, and a processing unit. The initialization unit is for entering initialization data into a database. The initialization data includes a first set of initialization data that is representative of characteristics of a first rotatable element, and a second set of initialization data that is representative of characteristics of a second rotatable element. The measurement unit is for permitting a user to enter measured data including a first set of measured data characteristic of measured features of the first rotatable element, and a second set of measured data characteristic of measured features of the second rotatable element.

Abstract: A system for predicting life of a rotary machine, includes a vibration gauge configured to measure time series data of a peak acceleration of the rotary machine; a band pass filter configured to filter an analog signal of the time series data of the peak acceleration measured by the vibration gauge in a frequency band including a first analysis frequency expressed as a product of an equation including a number of rotor blades of the rotary machine and a normal frequency unique to the rotary machine; and a data processing unit configured to predict a life span of the rotary machine by characteristics of the filtered analog data of the time series data of the peak acceleration with the first analysis frequency.

Abstract: A tire burst predicting device which can predict occurrence of bursting of a tire and gives an alarm properly is provided. A break point frequency is estimated on the basis of time series data of wheel speed detected at a wheel speed sensor from frequency response of a first order model to which a transmission characteristic from a road surface disturbance to a wheel speed is approximated. A braking force gradient corresponding to the estimated break point frequency is estimated, on the basis of a map, which is prestored, representing a relationship between break point frequencies and braking force gradients. Extra high frequency components are eliminated from the estimated braking force gradient by a low pass filter to reduce estimation dispersion. Differentiators detect changing speed of the braking force gradient. An alarm is given when there is a possibility of bursting of tire when the detected changing speed reaches or exceeds a predetermined threshold value.

Abstract: The present invention is a transient vibration time history testing calibration system and method that assists testing equipment reproduce predefined earthquake synthesized waveforms within acceptable parameters. Adjustments are made to forces applied to the equipment under test (EUT) so that the acceleration of the EUT corresponds to a predetermined acceleration time history waveform. Information associated with the acceleration time history waveform is loaded in a controller which produces shaker drive signals that control movements of a shaker. Two waveform tests are run at an attenuated value (e.g., ?3 dB) of a full level test on a dummy load. The acceleration of the dummy load is measured and adjustments are made to update the drive signals if the TRS is not within acceptable tolerances of the RRS. The adjustments are projected to provide shaker drive signals that shake the EUT within acceptable ranges of a RRS.

Abstract: An improved method for detecting the presence of humans or animals concealed within in a vehicle uses a combination of the continuous wavelet transform and a ratio-based energy calculation to determine whether the motion detected using seismic sensors placed on the vehicle is due to the presence of a heartbeat within the vehicle or is the result of motion caused by external factors such as the wind. The method performs well in the presence of light to moderate ambient wind levels, producing far fewer false alarm indications. The new method significantly improves the range of ambient environmental conditions under which human presence detection systems can reliably operate.

Abstract: A contact sensitive device includes a member capable of supporting bending waves and a plurality of sensors mounted on the member for measuring bending wave vibration in the member. The sensors measure the bending wave signals and by calculating a phase angle for each measured bending wave signal and a phase difference between the phase angles of least two pairs of sensors so that at least two phase differences are calculated, the location of the contact can be determined.

Abstract: A data collector having a digital signal processing circuit that receives a digitized vibration signal, and performs processing steps to isolate high frequency pulses in the digitized vibration signal and quantify energy content of those pulses by detecting a peak negative value of the digitized peak-to-peak amplitude of the received vibration signal, and then using this peak negative value to compute a maximum peak-to-peak value of the received vibration signal. Periodically, the maximum peak-to-peak value and peak negative value are reduced in magnitude by a decay factor, such that the peak negative value and maximum peak-to-peak value decay over time. The decay factors used in computing the maximum peak-to-peak value and peak negative value are determined by the digital signal processing circuit and may be readily changed.

Abstract: A drivetrain component assembly comprising a drivetrain structure, means for generating a reference signal indicative of a frequency with which the drivetrain structure vibrates during operation of the drivetrain structure, at least one actuator coupled to the drivetrain structure, at least one sensor operable for monitoring vibrations transmitted from the drivetrain structure and producing a sensor signal in response thereto and a controller coupled to the at least one actuator and the at least one sensor. The controller receives the sensor and reference signals and generates an actuator signal in response thereto. The at least one actuator receives the actuator signal and generates a canceling vibration in the drivetrain structure in response thereto. The canceling vibration has a predetermined frequency and amplitude to substantially cancel-out vibrations in a predetermined bandwidth that are generated during the operation of the drivetrain structure.

Abstract: A thrust jig with a concave-convex shape is pierced into a food sample to generate and detect an oscillation spectrum and an acoustic spectrum, which is analyzed in main component to calculate a main component value as the texture of the food sample.

Abstract: A noise or vibration control system improves the quality of adaptation estimates by filtering the input signals to the adaptation, selectively implementing a “dead-zone” during which adaptation does not occur and by selectively adding a dither signal to the control commands. The dead-zone is based on the magnitude of the changes in the control commands, which are responding to the changes in the sensor signals. The dead-zone can be applied to all actuators simultaneously, or can be applied to the adaptation of each actuator channel independently. To maintain identifiability, a “dither signal” is added to the control commands to “ping” the system to increase the amount of information available to the adaptive algorithm. The dither signal is preferably implemented on only one actuator channel at a time. Also, the dither amplitude for each channel is preferably set to be proportional to the current control amplitude.

Abstract: A system comprises a remotely situated plurality of sensors that sense information; a locally situated workstation that receives the information from the remotely situated plurality of sensors in the form of a set of data; and a Fast Fourier Transform (FFT) analyzer interfaced with the plurality of sensors and workstation to receive information from the plurality of sensors in the form of time domain data points, to transform the data points into a lesser number of frequency domain data points to facilitate transmission as a set of data from the plurality of sensors to the locally situated workstation.

Abstract: Measurement is made of centrifugal force produced on a crankshaft to be tested that is being rotated about its rotation axis, to provide centrifugal force variation information of the crankshaft. Also, measurement is made of errors in respective rotational phases of crankpins of the crankshaft about rotation axes of the crankpins. Dummy information, comprising rotational unbalance data representative of rotational unbalance components to be removed from the centrifugal force variation information of the crankshaft, is created using the measured errors in the respective rotational phases. Then, an initial rotational unbalance value of the crankshaft is determined, using the dummy information and the centrifugal force variation information of the crankshaft.

Abstract: A system for monitoring a plumbing system having a plurality of fixtures includes a sensor vibrationally coupled to the plumbing system and a processor. The sensor detects a vibration produced by the plumbing system, and generates a signal representative of the vibration. The processor receives the signal, compares the signal to a signal database that associates each of a plurality of stored signals with operation of one or more of the fixtures, and determines that the associated fixture or group of fixtures has been operated based on the comparison. The processor also stores a record of the operation of the associated fixture or group of fixtures.

Abstract: A method and system for analyzing hydraulic turbine noise vibrations involves recording the noise of a hydraulic turbine either during operation or intentionally produced for testing from a remote site. A standard laptop computer is utilized by personnel at the turbine site to record the sound at different power outputs as specified by turbine experts with a standard Windows sound recording program that produce sound files. The sound files are compressed at the site and sent to the expert office location via Email. Once received at the expert location, the sound files are uncompressed and analyzed immediately by the turbine experts without the experts having had to travel to the remote site. The analysis is done with a software sound analyzer. The analyzed signals are used to diagnose the machine and address any unusual recorded noise.

Abstract: A method facilitates simultaneously balancing mechanically coupled, synchronously rotating rotors. The rotors have different axes of rotation relative to one another and together define a rotor group to be balanced. Each rotor has at least one of a bearing plane and an other measuring plane associated therewith, the other measuring plane significantly describing vibrations of the each rotor. The rotors within the rotor group together have a number of different angular velocities associated therewith. At least one rotor of the rotor group is equipped with at least one vibration pickup in at least one of each bearing plane and the other measuring plane thereof. As many impulse and phase transmitters are installed in the rotor group as are provided the number of different angular velocities associated with the rotors within the rotor group.

Abstract: Data are collected for deriving response models and information required for developing and maintaining processes and process tools. Methods and apparatus for collecting the data include a process tolerant sensor apparatus capable of collecting data with less perturbation and fewer disruptions than is usually possible using standard methods.

Abstract: The present invention is an apparatus for detecting machine parameters including vibration, producing signal corresponding to the parameters and conditioning the signals by means of predetermined criteria such as amplitude and time criteria. Routes may be input to the analyzer with settings that govern part of the conditioning for individual machines. The predetermined criteria also may include an input limit criterion which ensures the safety of the analyzer circuitry by indicating attenuation levels for incoming signals. The analyzer is also capable of two channel analysis of input signals including a summing analysis. The analyzer has thumb operated controls for easy operation in harsh environments.

Abstract: A numerical controlling unit that accelerates or decelerates a feeder-driving system includes; an acceleration setting part that can set a volume and a timing of an acceleration that should be supplied to the feeder-driving system, based on a predetermined target condition; and a controlling part that can supply the acceleration set by the acceleration setting part to the feeder-driving system. The acceleration setting part is adapted to set: a first acceleration that starts to be supplied at a timing of starting to accelerate; and a second acceleration that has a volume and that starts to be supplied overlappedly with the first acceleration at a timing, the volume and the timing being determined so as to damp vibration of the feeder-driving system that is generated by starting to supply the first acceleration.

Abstract: The invention is directed to a monitoring system device attachable to a mechanical press, to measure long term reliability press conditions while in production operation. The device includes signal processing circuitry for processing a corresponding signal developed from an accelerometer. The signal processing circuitry has acceleration processing circuitry for calculating a press acceleration signal, a velocity processing circuitry for calculating a press velocity signal, and displacement processing circuitry for calculating a press displacement signal. Display circuitry is used for displaying at least one of said calculated signals.

Abstract: A system and method are provided for allowing simplified access to the raw vibration data. The signal conditioner, even if mounted on the engine or the engine pylon, digitizes the input signals and can analyze and store a finite amount of raw data. The raw signals are digitized at a high rate of speed, and the digitized values are stored. The stored values can be retrieved after flight. This aircraft vibration processor and recording system allows easy access to the raw vibration waveform, even in configurations where the processor is located on the engine or the engine pylon.

Abstract: Methods for determining a vibratory excitation spectrum are tailored to physical characteristics of a structure having critical elements located thereon to be subjected to vibration testing, such as a PCB to which connectors, resistors, capacitors, inductances, Integrated Circuits (IC) or Ball Grid Array components (BGA) are mounted. The physical characteristics includes a frequency response function corresponding to a testing environment temperature and defined in term of power spectral density amplitude over a global excitation frequency range for the vibratory excitation spectrum and characterized by a plurality of power spectral density amplitude peaks corresponding to a plurality of natural resonance frequencies, each being associated with respective mode shape and damping factor.

Abstract: Object of this invention is to provide an axial torsional vibration measurement device of the reactor internal pump capable of measuring the axial torsional vibration easily. The vibration detector 2 that detects vibration in the radial direction, and the sound detector 3 that detects vibration in the circumferential direction are fitted on cylindrical motor casing 6, which contains the motor of a reactor internal pump. The dimension of both signals of a vibration waveform signal detected by the vibration detector 2, and a sound waveform signal detected by the sound detector 3 are matched in vibration calculating device 15, to thereby obtain an axial torsion vibration of a motor from the difference of both signals.

Abstract: Methods and systems for determining the resonance frequency of a resonator, using the Doppler effect. An interrogating sonic beam including a carrier frequency and one or more resonator exciting frequencies is directed at a resonator disposed in a measurement environment. Resonator vibrations are excited by the resonator exciting frequencies. The carrier frequency is modulated by the vibrating part(s) of the resonator. The returning signal is received and analyzed to determine the amplitude of the Doppler shifted sideband frequencies. The resulting data is processed to determine the resonator's resonance frequency. Using calibrated resonating sensors having a resonance frequency that varies as a function of a physical parameter in a measurement environment, the method and systems allow determining the value of the physical variable from the sensor's resonance frequency.

Abstract: In a method for determining a mass airflow in an air duct using a mass airflow sensor, sensor signals at successive times, indicating the magnitude of the mass airflow, are captured and, using a characteristic curve for the mass airflow sensor, corresponding values are determined for the mass airflow. In doing so, a time series of signals is subjected to a vibration analysis, which determines a fundamental vibration and at least one prescribed harmonic vibration of the fundamental vibration, and the existence of a backflow is established if the ratio of the strength of the harmonic vibration to the strength of the fundamental vibration exceeds a prescribed threshold value.

Abstract: An acceleration sensor, installed together with an angular velocity sensor in the same casing, detects the acceleration induced by the external vibration. Its detection signal Vs is supplied to first and second band-pass filters to extract a driving system resonance frequency fd of the angular velocity sensor as well as a difference frequency &Dgr;f between the driving system frequency component and a sensing system resonance frequency. The extracted signals Vs1 and Vs2 of respective frequency components are supplied to first and second window comparators. When each frequency component deviates from a predetermined range, a diagnostic signal Vd notifying the abnormal condition of the angular velocity sensor is produced.

Abstract: A method according to the present invention calculates a performance function for a structural system (10) that can be used to determine system dynamics at points of interest on the structural system (10). A test input force is applied to an input subsystem (12) and an output subsystem (14) while the motion in response to the test input force is measured to determine a drive point transfer function. A test relative force is applied to the input subsystem (12) and output subsystem (14) at interface points in all degrees of freedom while the motion in response to the test relative force is measured in all degrees of freedom to determine the interface transfer functions. A performance function for the structural system (10) is mathematically calculated based upon the measured drive point transfer functions and interface transfer functions.

Abstract: To provide a vibration-damping positioning controller capable of effecting stable positioning operation within a short period of time.

Abstract: A portable self-contained data collection system for measuring and collecting vibration data from machines includes an accelerometer coupled to the analog input of a data acquisition card that samples and digitizes the analog signal to produce a time domain digital signal. The data acquisition card output is coupled to a battery-powered portable computer that includes a database having machine identifications and associated measurement parameters. The portable computer processes the time domain digital signal according to the measurement parameters associated with a selected machine identification, and produces a frequency domain digital signal by performing a Fast Fourier Transform and other digital signal processing operations. The frequency domain signal is also analyzed in the portable computer to produce predictive maintenance information. A power supply for supplying power to the accelerometer is also included.

Abstract: A system and method for analyzing vibrations signals thereby identifying damage or original manufacture defects in a vibrating device. In one embodiment of the invention, the method comprises collecting vibration signal data from at least one vibrating device, wherein the vibrating device includes at least an rotating inner ring, a rotating outer ring, and a plurality of rotating elements. The vibration signal data is enveloped and converted into a frequency domain signal. The amplitude of the frequency domain signal at certain defect frequencies is divided by a noise floor to provide a damage index. If the damage index exceeds an adjustable user-defined threshold, a warning is generated so as to alert a user of damage or original manufacture defects in the vibrating device.

Abstract: A nondestructive inspection method for composite structures, including thick core structures, is disclosed that imparts a vibration force into the structure and analyzes the response over a range of frequencies to find possible damaged areas. The composite structure is struck to induce vibration at a series of test points and the response of the composite structure as a function of acceleration at each test point is measured. The structural anomalies in the composite structure occur at structural stiffness irregularities near anomalies and are detected with a Gapped Smoothing Method operating on the data and plotting a structural irregularity index as a function of frequency and position.