Abstract: An apparatus for determining the torsional stiffness of a shaft comprises a rigid frame having a collet for securing one end of the shaft to be measured the rigid frame. A second collet secures the opposite end of the shaft to an inertial weight, which is supported for rotation by a separate bearing so that the inertial weight introduces no axial load in the shaft being measured. The inertial weight has mounted to it a biaxial accelerometer, optical gate or other electronic means for measuring the torsional frequency of the shaft/weight combination. When the inertial weight is displaced from the initial static position and released, the inertial weight oscillates about its center of mass under the urging of the torsional stiffness of the shaft. A computer is programmed with the mass moment of inertia of the inertial weight and therefore is able to solve the differential equation of motion for the torsional spring constant of the shaft based on the frequency of oscillation.

Abstract: The present invention provides a portable test system for in-situ, non-destructive identification of visco-elastic material. The system includes a probe-like member coupled to a controller, wherein the controller is responsive to an output signal from the probe-like member for determining properties of the visco-elastic material. The probe-like member includes a longitudinally extending housing. A transducer mechanism is operably positioned within the housing. The transducer mechanism includes an indentation tip member, wherein the indentation tip member is extendable through the housing. A load mechanism is provided for loading the transducer mechanism with a desired constant load, causing the indentation tip member to extend through the housing to perform an indentation. A force calibration mechanism is provided for calibrating the application of a fixed force between the indentation tip member and the visco-elastic material.

Abstract: The present invention provides a method and device for measuring granule impact strength by vibrating a small container of granules at a well-controlled amplitude in order to inflict reproducible damage to the granules. Damage to the granules is measured as a function of time and amplitude. The measurements obtained yield a highly reproducible method and device for characterizing granule attrition and fragmentation.

Abstract: A method of monitoring of the level of compaction of a soil surface undergoing compaction by an impact compactor which includes a rotatable, multi-sided compactor mass that applies periodic impact blows to the soil surface when rolled over that surface. In accordance with the invention, data related to the level of compaction of the soil surface is derived, during compaction of the soil surface, from the deceleration of the compactor mass as it impacts the soil surface. This is achieved using one or more accelerometers mounted on the impact compactor.

Abstract: In compacting an asphalt layer which is continuously deposited by a paver machine, a compacting machine reciprocates behind the paver. With the aid of signals from sensors (3) for temperature, sensors (5) for movement velocity of the compacting machine, sensors (7) for change of path, and sensors (9) for static/vibratory compacting operation, a processor (1) determines the position of the compacting machine continuously in relation to the paver, and other variables for each area segment passed by the compacting machine. The position of the compacting machine is displayed symbolically on a monitor (19) and the variables measured and determined for each passed area segment are stored in a memory (17). For each passed area segment, a total index number can be determined for this area segment, which on the monitor (19) is displayed as a field having a color or light intensity which is proportional to this total index number.

Abstract: A firmness measuring method and device for non-destructive testing of objects (such as fruits) is disclosed. The device comprises the following components: a means to affect the size and/or shape of the object(s) through application of a compressive force (such as increased liquid, fluid, or mechanical pressure); or an expansive force (such as decreased liquid, fluid, or mechanical pressure); a means to measure or infer the volumetric change of the object(s) caused by application of the force; and/or measurement of surface deformation; an analyzer to utilize the volume change and/or amount of deformation of the surface caused by the applied force to infer the firmness of the object(s); a controller to coordinate the application of force, the measurement of object(s) response and the inference of firmness or firmness. Inference of firmness may also use additional information on the object(s) such as harvest date, manufacture date, weight, variety, chemical concentration, or water content.

Abstract: A hardness measuring apparatus in which a frequency deviation detecting circuit is used has a contact element, an oscillator, a self-oscillating circuit and a gain variation compensating circuit. The self-oscillating circuit feeds back oscillation information of the oscillator to generate a resonant state. The gain variation compensating circuit is disposed in the self-oscillating circuit. The gain variation compensating circuit has a central frequency different from that of the self-oscillating circuit, and increases gain in response to a change in frequency.

Abstract: The invention relates to non-destructive measurement of the firmness of fruits and vegetables, particularly to methods and equipment for measuring the firmness of such edible objects in order to establish their ripeness or maturity stage, not only after they have been harvested or stored, but also during the growing process.

Abstract: To test the quality of solder bonded lead connections of a package by applying a shearing force to the leads using ultrasonic vibration and by measuring the resultant strain. A probe 32 is pressed against the surface of a lead 12 and vibrated by a piezoelectric element 38 in parallel with the lead surface to apply a shearing force to the solder bond portion. The resultant strain occurring in the solder bond portion is correlated with current and impedance of the piezoelectric element 38. By measuring the current and/or impedance of the piezoelectric element, the quality of the solder bond portion can be determined. Thus, a circuit board is produced having solder joints whose maximum strain in reaction to load is limited by the amount exhibited by a good joint.

Abstract: There are provided an elasticity measuring method of measuring an elastic constant of elasticity of an elastic body, for example, an elastic rubber, an organism or a living body, etc., which is soft and rather incompressible, by means of measuring an internal strain using energy such as ultrasounds, an X-ray, and magnetism, where the elastic constant includes, for example, typically shear modulus, Young's modulus, etc.; and an elasticity measuring apparatus adapted to practice such an elasticity measuring method. According to such method and apparatus, the elastic constant distribution within the subject is detected only through measuring the strain distribution within the subject, without measuring the stress distribution.

Abstract: Material is periodically indented by a probe driven at an oscillation frency by a shaker regulated by an analyzer to which input measurement data is fed from a sensing head connecting the shaker to the probe for in situ measurement of material resistance to indentation to which such input data relates. A computer connected to the analyzer is programmed to calculate steady-state data on dynamic material properties as a time dependent function, from outputs of the analyzer restricted to limits determined from the input measurement data.

Abstract: A scanning micro-sclerometer measures changes in contact stiffness and correlates these changes to characteristics of a scratch. A known force is applied to a contact junction between two bodies and a technique employing an oscillating force is used to generate the contact stiffness between the two bodies. As the two bodies slide relative to each other, the contact stiffness changes. The change is measured to characterize the scratch.

Abstract: An apparatus 400 and a method are provided for increasing the density of a compactible material 10 while continuously evaluating the density of the material. The evaluation of material density is carried out by calculating the total of the static, dynamic and centrifugal forces applied by a vibrating tool 102 l to the compactible material 10. The total applied force calculation includes measuring the vertical acceleration of the material contacting member 102 and the position of an eccentric mass 206 mounted on the material contacting member 102. The acquisition of these parameters is carried out simultaneously, and the calculation of the dynamic and centrifugal forces is made when the material contacting member 102 is at its lowest position.

Abstract: An apparatus and a method are provided for controlling the frequency of vibration of a compacting machine. The frequency control is carried out by the apparatus which determines the actual time at which a ground contacting member of the compacting machine is at its true vertically lowest position. This is determined by measuring the time at which the vertical acceleration of the ground contacting member has a maximum value during one rotation of an eccentrically mounted, vibration inducing mass. The time difference between the time at which the vibration inducing eccentric mass is at predetermined position and the time at which the acceleration of the ground contacting member is at the maximum value is used to calculate a phase angle relationship (.phi.) between the ground contacting member and the eccentrically attached member. This method of determining the phase angle relationship (.phi.

Abstract: An oscillation degree measuring apparatus measures the fixing state of an object to be measured as a numerical value of the degree of oscillation and comprises an ultrasonic exciter for generating ultrasonic waves which shock the object and exciting oscillations, an oscillation detector for detecting the oscillations of the object and converting the oscillations into electrical signals, a band amplifier for extracting a signal element of a predetermined frequency band including a resonant frequency of the object from the detected signals from the oscillation detector, a smoothing circuit for smoothing the signals amplified by the band amplifier, an A/D converter for converting the signals smoothed by the smoothing circuit into digital signals, a control device for operating the A/D converter a plurality of times every time a predetermined time passes, and a data processor for finding an average value of a plurality of digital data obtained by the A/D converter and calculating the degree of oscillation based o

Abstract: A device for measuring the strength of pieces of compressed molding material. The device includes a probe pin and a stop surface arranged on the housing. On the end of the housing opposite the probe pin is arranged a cover for replacing batteries arranged within the housing. When the probe pin is inserted into the compressed molding material, a digital display indicates the resistance to insertion measured by a crystal unit converted as molding material strengths in N/cm.sup.2 or PSI.

Abstract: The invention provides a friability testing apparatus which has an electrically excitable vibrator (10, 12) for vibrating a capsule (14) containing material to be tested. The apparatus includes a microprocssor (20) which proivdes an output waveform with a frequency which is determined by an oscillator (22). The output of the microprocssor drives a power amplifier (18) which controls the vibrator. An accelerometer (16) supplies signal to the microprocessor, so that the operation of the vibrator is maintained within predetermined limits.

Abstract: An apparatus for testing hardness under load has a measuring sensor in the form of a manual apparatus in which a mobile rod-shaped resonator can be slidingly inserted. The free end of the resonator, situated outside the housing, has a measuring tip. The resonator is held against the housing of the measuring sensor by a spring and is linked to ultrasonic converters connected to an electronic generator and to a receiving circuit which records changes in the duration or frequency of the vibrations of the generator. A basic apparatus comprises a display unit and is connected by a connecting line to the measuring sensor. A memory for storing individual parameters of the rod-shaped resonator and the electronic generator is arranged in the housing of the measuring sensor. The basic apparatus is detachably connected by insertion to the measuring sensor.

Abstract: The dynamic indentation system cyclically indents a test material for the purpose of determining mechanical properties that cannot be measured directly, such as in-plane wall stress in intact hearts. A probe or an end surface thereof cyclically indents the test material while the indentation stress acting on the face of the probe and the position of the probe are measured. The indentations can be servo-controlled for added stability.The transverse stiffness of the material is calculated as the slope of the relation between the indentation stress and indentation strain during each indentation cycle. The transverse stiffness is then used as an estimate of wall stress, and the relation between the transverse stiffness and in-plane strain can be used as a direct estimate of material properties.The dynamic indentation system is suitable for estimating in-plane wall stress and material properties from different parts of a test material.

Abstract: The method and apparatus for the non-destructive evaluation of a concrete mass uses the maturity method for evaluating the strength and durability of the concrete mass. The apparatus employs sensors which are implanted in the concrete along with a microprocessor and non-volatile RAM or EEPROM. A microcomputer is used periodically to up load the RAM and to make an evaluation of the concrete mass.

Abstract: Apparatus and method for use in measuring the softness of a fibrous product comprises a piezoelectric polymer film sensor, preferably polyvinylidene (di)fluoride with adhered opposed electrode surfaces, a sample of the fibrous product in direct contact with one of the sensor electrode surfaces, acutation components acoustically activating the fibrous product sample to cause the film sensor to generate an output electrical signal, and a spectrum analyzer for characterizing the fibrous product softness from the output electrical signal.

Abstract: Method and apparatus for providing an indication of compaction in vibration compacting machines. A signal proportional to acceleration occuring when the working part of a vibrating compaction machine strikes soil is developed by means of an acceleration pick-up and is compared with a stepped sequence of potentials representative of preselected acceleration values. During consecutive observation intervals it is observed which of these potentials are exceeded and which are not exceeded by the maximum acceleration occuring in an observation interval. In one embodiment, a control signal is developed which provides an indication of the compaction. The control signal is used to change the preselected acceleration values dependent upon the degree of compaction. Another embodiment of the invention develops a signal which is used to change the distance between the preselected acceleration values independent of the control signal.

Abstract: The present invention is a method and apparatus for measuring the average hardness of a metal. This method capitalizes on the discovery that a longitudinal wave will travel roughly twice as fast as a transverse (shear) wave, the times-of-flight of the two waves are affected to different degrees by hardness, and there is a linear relationship between velocity and hardness. Longitudinal and transverse ultrasonic signals are applied to a first end (face) of the metal. The longitudinal and transverse signals are detected at this same first end of the metal after they are reflected off of the second end (face) of the metal. The time-of-flight for each of the longitudinal and transverse waves is measured. The hardness, H, in the metal is then determined by applying substantially the following equation: ##EQU1## where: H.sub.1 =known hardness for the hard phase of the metal;h=a constant for the metal alloy;R=measured ratio of shear and longitudinal times of transit; andR.sub.

Abstract: An apparatus for discriminating and sorting out defective plastic bottle crates from sound bottle crates comprising driving means for urging an indenter or contact tip provided at the tip of a vibrating rod of an ultrasonic hardness tester into steady contact in indented state with a bottle crate, detecting means for detecting resonant frequency of said vibrating rod which is varied by the urging of said indenter or contact tip into steady contact with said bottle crate, and means for distinguishing and sorting out defective bottle crates from sound bottle crates in response to the resonant frequency detected by the detecting means.

Abstract: This invention discloses a method and apparatus for determining the hardness of a solid workpiece. An elongated rod is excited to be mechanically resonant along its longitudinal axis and is provided at its front end with a defined contact surface of hard material (Vickers diamond). When the rod is rendered resonant at its natural frequency of vibration .omega.o, the contact surface of the rod is pressed into the surface of the workpiece, whose hardness is to be determined, under a predetermined engagement force while the rod is forcibly maintained oscillating at the frequency .omega.o. A sensor coupled to the rod provides a signal indicative of the amplitude of vibrations of the rod when in forced contact with the workpiece and such signal is fed to a computing device for providing a value indicative of the hardness of the workpiece.

Abstract: A circuit automatically determines the nature of the seabed over which a vessel is passing, indicating via an audible or other warning signal when a fishing vessel is above a type of seabed which might damage the fishing net. The circuit is responsive to an echosounder signal and raises an alarm when a amplitude of the second bottom echo component in the echosounder signal exceeds a selected threshold level. Preferably the analog echosounder signal is subject to threshold discrimination to provide a pulse-form signal which is then processed by a digital logic circuit to isolate the second bottom echo component.

Abstract: Object deformations are analyzed by recording interferometric images using a television camera. The camera's photosensitive recording cathode is successively exposed to interferometric images of the object, respectively before and after a stress is applied to the object, while the camera's scanning beam is blanked out in order to record a composite image having fringe families arrayed as a function of the deformation of the object. Subsequent scanning of the cathode produces video signals representing variations of intensity in the superimposed illumination patterns of the composite image. The video signals may be digitized, analyzed and displayed on a cathode ray tube.

Abstract: The invention is directed to a measuring apparatus for determining the degree of compaction of material for building dams, roads or the like after the material has been compacted with a suitable compaction machine. The measuring apparatus includes a vibrating drum which is equipped with a transducer for generating signals while the drum is run over the ground surface for which the degree of compaction is to be determined. In order to eliminate factors which impede evaluation of the signals emanating from the signal transducers, the drum is configured so that its contact surface with the ground surface is as restricted as possible. This can be achieved by reducing the width of the drum.

Abstract: A method for measuring the physical properties of material comprising the steps of producing a tone burst wave by a tone burst wave oscillator, radiating acoustic energy of the tone burst wave onto an object to be measured to cause vibrations therein, detecting the vibrations as a waveform of an alternating wave at a vibration receiver, obtaining a gradient of a line which connects peaks in a first transitional region of the waveform from which can be determined the physical properties, in particular the energy transfer characteristics and/or restitution coefficient of the object.

Abstract: A resonant sensing device for measuring the hardness of a workpiece to be tested includes a diamond tipped rod adapted to be resonant and for determining the hardness of a workpiece to be tested is brought into forced contact with such workpiece. The difference in resonant frequency of the rod between its not-constrained condition and its constrained condition (forced contact) is a measure of the hardness of the workpiece. The present invention describes a circuit wherein during a first time interval an up/down counter accumulates the counts arising from the oscillations of the not-constrained rod. During the ensuing interval of the same duration, the counter counts down the accumulated count responsive to the oscillations of the constrained rod.

Abstract: A method and apparatus for the non-destructive testing of materials, particularly composite structures and other such laminated materials, which comprises repeatedly impacting the material being tested with a precisely regulated force having a pre-determined magnitude. The response generated by the material is detected by a sensor and a proportional electrical signal is generated. The electrical signal is compared with a stored electrical signal previously generated in response to impacting a defect-free reference material with the same precisely regulated pre-determined force. A difference in frequency and amplitude between the two compared electrical signals is indicative of a defect in the material being tested.

Abstract: The disclosure describes a method for checking an insulative condition of an insulated winding used in an electrical appliance comprising applying an external mechanical force to said insulated winding to give vibrating frequency to the same for its examination; detecting the frequency behavior to be generated in said insulated winding in the form of electrical signal outputs; and electrically processing the signals for judging deterioration occurred in said insulated winding.

Abstract: The invention refers to a procedure and a device for measuring the degree of compaction attained when compacting a foundation by means of a vibrating compaction tool. The movement of that part of the compaction tool which rests on the foundation is sensed and analyzed. The time interval elapsing between successive passages of the movement signal through the zero point or other reference level is measured. Alternatively, the ratio between the absolute values of the extreme positive and extreme negative values of the motion in relation to the said level is also measured. By means of the relative magnitudes of these time intervals and amplitude relationships respectively a quantity is formed which comprises a measure of the degree of compaction of the foundation.

Abstract: A terrain probe for sensing the elevation of a terrain surface whose prof is being measured and followed. A two-phase induction motor will raise or lower the terrain probe in response to either an increase or decrease in the elevation of the terrain surface. A four arm bridge circuit, which has an arm enclosed within the terrain probe, in combination with a low frequency oscillator, a differential amplifier, and power amplifier generate a sinusoidal drive signal which controls the two-phase induction motor.

Abstract: A device for ascertaining the degree of compaction of beds of material with a vibratory compaction device as a function of the vibratory amplitude of the motion of the compaction device at selected frequencies is described. The amplitude of vibratory motion of a compaction device is measured at a fundamental frequency and at least the second harmonic of the fundamental frequency and a ratio of the measured signals is computed. The ratio or quotient of the two signals provides a representation of the degree of compaction of the material being compressed by the compaction device. The ratio or quotient may be utilized either as a direct indication to an operator of the degree of compaction or as a control signal in an automated servo control compaction system.

Abstract: A hand held ear test probe is disclosed for use in clinical evaluations of hearing problems. There are a number of important tests for evaluating hearing system losses which are based upon measurements taken in patients' external ear canals using a test probe. A probe is described for such tests which is inserted in the patient's ear and which is hand held by the clinician without the use of head bands or other probe supports. The hand held probe has a shaped outer casing which supports the probe and the related ear sealing and pressurizing means as well as the transducers for the transmitted and received audio test signals.

Abstract: A device for ascertaining the degree of compaction of beds of material with a vibratory compaction device as a function of the vibratory amplitude of the motion of the compaction device at selected frequencies is described. The amplitude of vibratory motion of a compaction device is measured at a fundamental frequency and at least the second harmonic of the fundamental frequency and a ratio of the measured signals is computed. The ratio or quotient of the two signals provides a representation of the degree of compaction of the material being compressed by the compaction device. The ratio or quotient may be utilized either as a direct indication to an operator of the degree of compaction or as a control signal in an automated servo control compaction system.