Abstract: Methods of detecting pipeline weakening are described herein. The methods include creating a pressure wave in a fluid flowing in a pipeline using an input transducer located at a first position along the pipeline; measuring the pressure wave using an output transducer positioned at a second position along the pipeline that is spaced from the first position, and generating an output signal based on the pressure wave; analyzing the output signal to determine a stiffness of a sidewall of the pipeline positioned between the input transducer and output transducer; and determining if the sidewall includes a defect based on the stiffness of the sidewall, including analyzing a frequency response of the output signal to detect the defect.

Abstract: A method for monitoring a pantograph. The method includes acquiring an impulse response of the pantograph, extracting a natural frequency and a damping coefficient of the pantograph from the impulse response, obtaining a similarity factor of a plurality of similarity factors, and detecting a fault in the pantograph from the plurality of fault types based on the plurality of the similarity factors. Acquiring an impulse response of the pantograph includes generating the impulse response by tapping the head of the pantograph and recording the impulse response utilizing a recording equipment.

Abstract: A fatigue testing device 1 comprises a fixing member 4 constituted by a lower jig 2 and an upper jig 3. The lower jig 2 and the upper jig 3 are fixed with a bolt 5, and a sheet or plate-shaped metal plate 6 is fixed in a cantilever state such that it is interposed between the lower jig 2 and the upper jig 3. The lower jig 2 has a fixing surface 2a to which the metal sheet or plate 6 is fixed, and the fixing surface 2a has a curved shape such that the space between the fixing surface 2a and the metal sheet or plate 6 increases with increasing distance from the location where the metal sheet or plate 6 is fixed to the fixing surface 2a. The upper jig 3 also has a fixing surface 3a to which the metal sheet or plate 6 is fixed, and the fixing surface 3a has a curved shape such that the space between the fixing surface 3a and the metal sheet or plate 6 increases with increasing distance from the location where the metal sheet or plate 6 is fixed to the fixing surface 3a.

Abstract: A method for adjusting reactance includes an adjustable reactance generator including a comparator receiving an input sinusoidal waveform and outputting a square wave that retains the frequency and phase of the applied sinusoidal waveform. The reactance adjustment is generated using a power switching circuit that receives the square wave from the comparator as a control signal and outputs a square wave that retains the frequency and phase of the applied sinusoidal voltage waveform, an adjustable power supply that adjusts the amplitude of the square wave output by the power switching circuit, and an amplitude detector that controls the output level of the adjustable power supply. The power switching circuit output, when converted to a sinusoid, provides the effect of an adjustable reactance.

Abstract: A method and apparatus for an electromagnetic acoustic transducer. An apparatus comprises a conductive material and a current inducer. The conductive material is configured to generate a magnetic field, wherein the magnetic field has magnetic flux lines that are substantially fixed and the conductive material has a temperature that is equal to or less than a critical temperature at which the conductive material has substantially zero electrical resistance. The current inducer is configured to cause an electric current to flow in a test object that interacts with the magnetic field, wherein the electric current has a frequency that generates an acoustic wave in the test object.

Abstract: An acoustic emissions testing device includes a rock sample including a first surface, an acoustic sensor, an indenter coupled to the first surface, and a load. The load is exerted on the indenter, which transfers the load to the first surface. The acoustic sensor is communicably coupled to the rock sample and detects one or more acoustic events occurring within the rock sample. An acoustic emissions testing system includes a data recorder coupled to the testing device. The data recorder records the data from testing device. Based upon the data received, the toughness of the sample is objectively determined and can be ranked comparatively to the toughness of other samples. The load is ramped up to a peak load, held for a period of time, and then ramped down.

Abstract: The present invention provides systems and methods to use a measured driving-point response of a nonlinear material to determine one or more elastic properties of the material. The present invention takes advantage of the full information represented by the transient component, the steady-state component, the anharmonic components, and the nonlinear response components of a measured driving-point response of a real nonlinear material, without limitation in the use of large-amplitude forces. The elastic properties are determined by forming and solving a time-domain system of linear equations representing a differential equation model of the driving-point motions of the material. Based on a single, short duration, large-amplitude driving point measurement, both linear and nonlinear properties can be determined; both large-amplitude and near-zero amplitude properties can be determined; and elastic-wave speed and elastic moduli and their variation with depth can be determined.

Abstract: The present invention provides systems and methods to used a measured driving-point response of a nonlinear material to determined one or more elastic properties of the material. The present invention takes advantage of the full information represented by the transient component, the steady-state component, the anharmonic components, and the nonlinear response components of a measured driving-point response of a real nonlinear material, without limitation in the use of large-amplitude forces. The elastic properties are determined by forming and solving a time-domain system of linear equations representing a differential equation model of the driving-point motions of the material. Based on a single, short duration, large-amplitude driving point measurement, both linear and nonlinear properties can be determined; both large-amplitude and near-zero amplitude properties can be determined; and elastic-wave speed and elastic moduli and their variation with depth can be determined.

Abstract: A system and corresponding method for determining the frequency and/or amplitude of an oscillating apparatus, which includes a driving assembly having a stator portion and an armature portion, and a driving signal circuit which supplies a driving signal to the stator portion. A control circuit interrupts the drive signal momentarily, for at least a quarter of a cycle, at periodic intervals, resulting in a signal being induced into the stator coil from continuing movement of the armature. A measurement/read circuit is connected to the stator coil for determining one or both of the frequency of the induced signal and the amplitude of the induced signal. The frequency or amplitude information is then compared against pre-established values and any differences are used to change the driving signal so as to provide maximum performance of the appliance.

Abstract: A method of operating a knock detection system of a multi-cylinder piston engine in which the knock detection system comprises a sensor arranged in connection with each cylinder and a measurement circuit connected to the sensor includes running the engine at a load being less than full load and setting the output signal of each separate sensor between certain preset limits by adjusting one or more adjustment variables of the measurement circuit. The values of the adjustment variables for each separate cylinder are stored in the detection system. During normal use, the engine is run and the previously stored values of the adjustment values for each cylinder are used in the knock detection system.

Abstract: This invention relates to a Electromagnetic Acoustic Transducer which has the ability to detect flaws in assorted metallic objects, such as pipes, rods, bars and the like, including those objects which are already installed and cannot be removed without a major undertaking. The Transducer also has an embodiment which includes hinged arms for surrounding the circular objects that have already been installed such as piping. The system employs Lamb waves to move along the surface of metallic objects to affect a bounced return to thereby allow detection of flaws on the surface or in the interior of said objects.

Abstract: In a method of detecting damage in materials or objects (4) the material or object is physically influenced to produce a physical change of the material or object inducing transient slow dynamics in case of damages in the material or object. Slow dynamics induced material elastic modulus changes are detected as indication of damages of the material or object. In a device for non-destructive detection of damage in materials or objects (4), an impact source (16) is provided to impact the material or object to physically influence the material or object to produce a physical change of the material or object inducing transient slow dynamics in case of damages in the material or object. A detector (2,8,10,12,14,6) is provided to detect by said slow dynamics induced material elastic modulus changes as indications of damages of the material or object.

Abstract: A palm-held acoustical sensing device provides improved accessibility within an engine compartment for sensing engine noise in order to perform diagnostics. Miniaturized electronics are provided within a compact housing that permits free use of the sensing device within an engine compartment, enabling access to engine components that have previously been accessible only with great difficulty. Clamping sensors having wider bandwidth than existing clamping sensors provide improved sensing capability and an electronics and battery housing having one or more sensor input jacks provides for attachment of multiple sensors, improved storage and a lower cost unit providing the advantages of both a flexible shaft sensing unit and a clamping unit.

Abstract: A method for determining the sensitivity of the fatigue life of a structural component with respect to specific design parameters includes obtaining the stress profile for a structural component under random process establishing a relationship between the stress profile and the fatigue life of the structural component, developing the sensitivity of the fatigue life with respect to design parameters, optimizing the design of the structural component based upon the design parameters to which the fatigue life is most sensitive.

Abstract: The present invention relates to a method and apparatus for detecting anomalies, defects or electromagnetic properties of electrically conductive and magnetically permeable materials by using a magnet to partially saturate the material, thereby lowering its permeability, and sending a second, higher frequency oscillating electromagnetic wave into the material. The oscillating magnetic flux field permeating into the electrically conductive material induces eddy waves. As the apparatus passes over the material, the properties of the induced eddy currents, and the corresponding magnetic flux field induced by such eddy currents, changes as the properties of the material change. These changes can be the result of defects or anomalies in the material or in connecting welds.

Abstract: A capacitance probe measures and tracks frequency and amplitude changes of a component during a high cycle fatigue portion of a life test. The probe includes an internal oscillator, an adjustable receiver circuit, a product detector, and a pair of gain amplifiers. The oscillator generates a single controlled frequency output. The receiver circuit receives the frequency and creates a DC voltage shift that nulls the capacitance bridge. The product detector detects an amplitude modulated product of the oscillator and rejects undesirable frequencies. The gain amplifiers detect a DC voltage shift and permit the capacitance effect to be easily nulled.

Abstract: The present invention relates to a method and apparatus for detecting anomalies, defects or electromagnetic properties of electrically conductive and magnetically permeable materials by using a magnet to partially saturate the material, thereby lowering its permeability, and sending a second, higher frequency oscillating electromagnetic wave into the material. The oscillating magnetic flux field permeating into the electrically conductive material induces eddy waves. As the apparatus passes over the material, the properties of the induced eddy currents, and the corresponding magnetic flux field induced by such eddy currents, changes as the properties of the material change. These changes can be the result of defects or anomalies in the material or in connecting welds.

Abstract: A method and system for strategically arranging drive assemblies within a multiple drive array that includes multiple drive locations. First, a vibration classification is assigned to each drive location among a plurality of drive locations within a multiple drive array, each vibration classification corresponding to a range of measurable vibration levels acceptable at each of the plurality of drive locations. Next, an inherent measurable vibration level of a selected drive assembly that will be installed within one of the drive locations is determined. Finally, the inherent measurable vibration level of the selected drive assembly is correlated with a preferred vibration classification of a particular drive location, such that the selected drive assembly may be optimally located within said multiple drive array.

Abstract: An application program and computer system for determining the testing profile for accelerated laboratory random vibrational testing of a product, including the application program steps of (i) selecting the frequency range covered in the laboratory accelerated testing, (ii) developing a simplified composite Power Spectral Density function PSD.sub.j (f) representative of the PSD for random vibration loadings in expected field vibration levels, (iii) developing the shape of PSD.sub.T for producing on the product the test acceleration forces corresponding to the PSD.sub.j function, (iv) calculating the stress response curve H(f) for the product representative of the transmissibility function from the input acceleration forces to the local vibration stress forces, (v) selecting the test duration, and then calculating the amplification factor from the relationship ##EQU1## (vi) recalculating the accelerated PSD profile, PSD.sub.

Abstract: A method and apparatus for evaluation and inspection of a composite-repaired structure generates a frequency-varying electrical signal to test and evaluate the composite-repaired area. The electrical signal is converted into a mechanical signal and transmitted through the composite-repaired area of the structure. The transmitted mechanical signal is received and converted into an electrical signal for processing. The processed signal is compared with a baseline reference signal to determine whether the composite-repaired area is damaged or undamaged. The baseline reference signal is obtained at the time of the composite repair of the structure.

Abstract: A method for determining the testing profile for accelerated laboratory random vibrational testing of a product, including the steps of (i) selecting the frequency range covered in the laboratory accelerated testing, (ii) developing a simplified composite Power Spectral Density function PSD.sub.j (f) representative of the PSD for random vibration loadings in expected field vibration levels, (iii) developing the shape of PSD.sub.T for producing on the product the test acceleration forces corresponding to the PSD.sub.j function, (iv) calculating the stress response curve H(f) for the product representative of the transmissibility function from the input acceleration forces to the local vibration stress forces, (v) selecting the test duration, and then calculating the amplification factor from the relationship ##EQU1## (vi) recalculating the accelerated PSD profile, PSD.sub.

Abstract: A method and apparatus for controlling the oscillatory motion of a test device by using amplitude and DC offset feedback for control purposes. The force applied to the test device is monitored by a load sensor and compared to a preset desired amplitude load setpoint to determine the positive peak amplitude of a sinusoidal control signal. The DC offset feedback is monitored by sampling the value of a displacement feedback signal a number of times for each cycle of movement. The values of the samples are averaged to determine a calculated DC offset. The calculated DC offset is compared to a desired DC offset, which is determined from a preset desired displacement setpoint. The difference between the calculated DC offset and the desired DC offset is then used to control the load applied to the test device to maintain the desired oscillatory movement.

Abstract: A non-destructive examination device has an excitation current generation device for supplying an excitation current based on a control signal from a control device, a vibration excitor device for generating an elastic wave in accordance with athe excitation current and for vibrating an examination target to be examined by using the elastic wave; a response detection device (an acceleration sensor) for detecting a response of the vibration of the examination target caused by the elastic wave and for processing the response data in order to select desired examination information. The excitation current generation device generates the excitation current of an alternating pulse wave such as a pulse wave, or a rectangular wave, or a triangular wave, or a sine wave based on the control signal which is also a pulse signal. It can be acceptable to incorporate a plurality of the vibration excitor devices on the examination target in the non-destructive examination device.

Abstract: An electromagnetic source or sources in a sonde in a well bore is caused to emit electromagnetic forces into the well casing. The electromagnetic forces cause displacement of the casing, inducing acoustic waves. The acoustic waves may be either P-waves or S-waves, depending on the type of electromagnetic source used. The response of earth formations to the acoustic waves, once detected, is used to detect fractures in the formations.

Abstract: Device for fatigue-testing a mechanical component by exciting this component (1), to which massive armatures (2, 3) may be attached, using an electromagnetic vibrator (13) fed by a generator, characterized in that the said generator comprises a displacement sensor (14) placed between two parts of a vibrating assembly (1, 2, 3) and generating a sinusoidal signal; a root-mean-square value converter (5) converting this alternating signal into a direct current signal of root-mean-square value; and an analog divider circuit (7) receiving the sinusoidal signal as numerator (8) and the root-mean-square value signal produced by the said converter as denominator (6), with the output signal (9) from this divider (7) being used after amplification (12) to drive the electromagnetic vibrator (13) acting on the vibrating assembly.