Abstract: For efficient presentation of pseudo force sense, a pseudo force sense generation apparatus includes: a base mechanism; and a contact mechanism that performs periodical asymmetric motion relative to the base mechanism and gives force based on the asymmetric motion to skin or mucous membrane with which the contact mechanism is in direct or indirect contact. A mass of the contact mechanism is smaller than a mass of the base mechanism, or the mass of the contact mechanism is smaller than a sum of the mass of the base mechanism and a mass of a mechanism that is attached to the base mechanism.

Abstract: An object of the present invention is to provide a dynamic characteristic measurement device capable of accurately measuring dynamic vibration characteristics of a rubber isolator and the like in a high-frequency vibration range. A dynamic characteristic measurement device according to the present invention includes a base, a support part that is placed above the base so as to be capable of floating via an air spring, an electrodynamic vibrator that is provided on the base side of an object under test mounted between the base and the support part and vibrates the object under test, and a load washer that is provided on the support part side of the object under test and measures a dynamic load applied to the object under test. Here, a crosshead of the support part is shaped such that a resonant frequency is at least 3 kHz.

Abstract: A shaker for enabling the testing of gyros and/or other devices for performance under realistic 6DOF motions. The shaker may be implemented as a hexapod, comprising a plate and six individually, simultaneously, and real-time controllable strut assemblies that are capable of extending and contracting linearly. The strut assemblies may comprise high-precision, linear electromagnetic actuators. The strut assemblies may also comprise high-precision non-contact sensors to sense the extension/contraction of the strut assemblies along their stroke length. In addition, the strut assemblies may comprise, at each end thereof, stiff, bendable flexures to attain the repeatable and linear motion required. The controller preferably has a control bandwidth of 1000 Hz or more, so that the motion of the plate can be precisely controlled to realize realistic 6DOF motions.

Abstract: A testing apparatus, for subjecting a device-under-test to oscillating acceleration, includes a stage having a mounting surface attachable to the device-under-test. An actuator is coupled to the stage, and also coupled to a reaction mass movable along a linear axis. A first flexure plate has a first flexure plate middle and a first flexure plate periphery, with the first flexure plate middle attached to the stage at a first stage end. A second flexure plate has a second flexure plate middle and a second flexure plate periphery, with the second flexure plate middle attached to the stage at a second stage end that opposes the first stage end. The first flexure plate periphery and the second flexure plate periphery are attached to the frame. The first and second flexure plates define major surfaces that are substantially perpendicular to the linear axis.

Abstract: A vibration testing device to test vibration strength and frequency generated by an electronic device, includes a base, a vibration contact member, a transmission member, and a resilient member attached to the transmission member. The base includes a receiving space to receive the electronic device and a receiving hole in communication with the receiving space. The transmission member extends through the receiving hole and is rigidly attached to the vibration contact member. During testing, the electronic device directly abuts an end portion of the transmission member so that the vibration strength and frequency generated by the electronic device are directly transmitted to the vibration contact member.

Abstract: Provided is a device for testing an isolation structure comprising an isolation layer having an upper beam, a lower beam and a top beam plate, along with an upper portion, the device comprising a plurality of upper corbels, a plurality of lower corbels, a plurality of hoisting jacks, a plurality of acceleration sensors, a plurality of displacement sensors, an acceleration collecting analyzer and a displacement collecting analyzer. A method for testing an isolation structure is also provided.

Abstract: The invention relates to a handler for testing electronic components, said handler comprising an acceleration device (1) provided with a tappet (3) which is linearly guided by means of at least one flat spring (6) comprising two groups of spring arms (9, 11), one group being fixed to the tappet (3) and the other group to a frame (7) which is stationary in relation to a housing (21) of the movement generation device (2).

Abstract: An electro-shaker vehicle test stand for vehicle evaluation includes a support frame, an electro-shaker mechanism and an interconnecting lever arm. The lever arm has an adjustable length. The test stand includes a spring table having a spring table plate and a spring table frame that is parallel to and spaced a predetermined distance below the spring table plate, a guide rod having a lower end attached to the spring table frame and an upper end attached to the spring table plate and a spring having an upper end attached to the frame and a lower end attached to the spring table frame. Activation of the electro-shaker mechanism induces an oscillatory movement of the spring in a vertical direction so that the spring table and vehicle are correspondingly displaced in a vertical direction.

Abstract: A shaker assembly for shaking a tested component. The shaker assembly permitting a vibration to be induced within the tested component, such as for use in measuring operating characteristics of the tested component.

Abstract: A system for inducing shock may include a first slap plate attached to a shaker armature of a shaker table system to impart a shock to any object being tested by the system. The shock is amplifiable by use of the first slap plate compared to the object being coupled to the shaker armature without the first slap plate. The system may also include a specific attachment arrangement for attaching the first slap plate to the shaker armature. The specific attachment arrangement and a configuration of the first slap plate may be selected to control a level of shock imparted to the object being tested.

Abstract: An electro-shaker vehicle test stand for vehicle evaluation includes a support frame, an electro-shaker mechanism and an interconnecting lever arm. The lever arm has an adjustable length. The test stand includes a spring table having a spring table plate and a spring table frame that is parallel to and spaced a predetermined distance below the spring table plate, a guide rod having a lower end attached to the spring table frame and an upper end attached to the spring table plate and a spring having an upper end attached to the frame and a lower end attached to the spring table frame. Activation of the electro-shaker mechanism induces an oscillatory movement of the spring in a vertical direction so that the spring table and vehicle are correspondingly displaced in a vertical direction.

Abstract: The present vibration test module enables a test engineer in the field of vibration test systems to precisely implement a vibration environment that is applicable to a wide range of applications and performance characteristics. The vibration test module comprises adjustable vibration shaping elements that collectively function to enable the user to program the frequency and magnitude of the vibrations that are produced by the vibration test system. This energy redistribution is accomplished by providing tuned vibration absorbers, consisting of a bouncing mass enclosed in a housing having walls that are elastic and/or spring mounted and/or adjustable in position, which enable the test engineer to precisely shape the frequency response of the vibrating system by causing broad band vibration to be generated in the vibration test system by the series of impacts of the mass with the walls of its enclosure.

Abstract: A hollow composite structure is inspected using an ultrasonic inspection apparatus including a yoke having a base, a first arm extending from the base, and a second arm extending from the base parallel to the first arm. A first ultrasonic transducer is affixed to the first arm, and a second ultrasonic transducer is affixed by a spring mount to the second arm in facing relation to the first ultrasonic transducer. A retractor is affixed to the spring mount to permit the second ultrasonic transducer to be retracted away from the first ultrasonic transducer against a spring bias. The ultrasonic inspection apparatus is positioned by placing one of the arms adjacent to the interior surface, one of the arms adjacent to the exterior surface, and the base extending through the access opening.

Abstract: A shaker system (10) that employs a mechanical amplifier (40) for increasing the shaking capacity of the shaker (14). The mechanical amplifier (40) includes a spring (54) positioned within a support column (42) where the spring (54) is attached to an interface ring (24) supporting the load (26) to be tested at one end and the ground at an opposite end. The spring (54) can take on different configurations, and in one embodiment is a sinusoidal spring (54) having half-circle sections (60) of a predetermined radius to satisfy the resonant frequency requirements for a particular load. The resonant frequency of the spring (54) causes the shaking to be amplified, meeting the testing requirements.

Abstract: The multi-level vibration test system has controllable vibration attributes that enable the test engineer to precisely implement a vibration environment that is applicable to a wide range of applications and performance characteristics. The multi-level vibration test system comprises a plurality of shaker modules that are interconnected by coupling modules and optionally includes vibration input elements and/or vibration shaping elements that collectively function to enable the user to program the frequency and magnitudes that are produced by the multi-level vibration system. This novel architecture as well as the numerous implementation variations that are possible using this architecture, enable the test engineer to precisely control the vibration frequencies and magnitudes that are produced.

Abstract: A shaker table comprises upper and lower plates spaced apart by a plurality of spacers that fit between the plates. Each spacer has an upper shaft, which threads into a vibrator opening in the upper plate, and a lower coaxial shaft, which slides into a vibrator opening in the lower plate. The spacer has a threaded internal coaxial opening extending through the spacer. A bolt for securing a vibrator to the bottom of the table engages the internal opening and secures the vibrator and the lower plate to the spacer and upper plate. A mounting bolt for attaching a test product or test fixture to the top of the table threads into the internal opening from the top.

Abstract: This invention relates to an apparatus to test the resistance to vibration of brake beams for railway car truck assemblies having a union frame, a side frame at each end of the union frame, each having front and rear ends, and a pair of beam carriers, each having front and side end as well as a receptacle in each of its ends to receive a side guide of a pair of brake beams. A pair of vibratory devices, each mounted on the front end of the respective beam carriers, are coupled through a transmission to a driver providing a rotatory movement for testing. The union frame, side frames and beam carriers which support a pair of brake beams to be tested, reproducing a railway car truck assembly.

Abstract: A controlled vibration experiment device having a vibration model structure to simulate actual mechanical vibration and to monitor and analyze the vibration by a computer monitor. The device has a base plate, a supporting frame, a T-shaped sliding rail, a servo motor, a connecting piece and a decoder with a rotatable shaft. The vibration produced is changed to an electrical signal and input to the computer to display the various type of waveforms. The vibration phenomena is then analyzed by a computerized monitor.

Abstract: Method and apparatus for determining Young's Modulus of a specimen by measuring the speed at which stress waves, either P-waves or S-waves, propagate therein. An embodiment of the apparatus includes two fixtures which are removably affixed to opposite ends of the specimen. A hammer having an accelerometer affixed to its head is used to strike the first fixture to produce stress waves in the specimen. A timing means starts counting in response to an output generated by the accelerometer when the hammer strikes the first fixture. A second accelerometer affixed to the second fixture detects the stress waves and generates an output which causes the timing means to stop counting. Further circuitry extracts the measured time, calculates a dispersion time delay based on material and length, and subtracts the dispersion time delay and a predetermined constant, both dependent on the material in the specimen, from the measured time to form a corrected transit time.

Abstract: A shaker table (10) includes a table base (12) mounted upon isolating supports (32) and vibrated by vibrators (34, 36). The vibration is conveyed through and damped in a flexure member (16) comprising pairs (26, 28) of honeycomb layers (18, 20, 22, 24) joined and bonded together by sheets (42) utilizing beads of elastomeric adhesive which space the honeycomb layers apart. A segmented top plate (14) is secured to the topmost honeycomb layer and is divided into a plurality of sections or segments (68-82) for separate resonances. In this way, highly damped vibrational resonances of table top plate (14) are obtained.

Abstract: A convoluted flexible support structure is provided which is capable of supplying a lateral to axial spring rate in excess of 1,000 to 1. A support member in the form of a steel disc having a specified number of rather large radius, concentric convolutions and a thickness in the range of from about 0.01 to 0.02 inch has an axial stiffness of about 50 pounds/inch while the lateral stiffness is about 100,000 pounds/inch. The support member may be used to support a vibration device where the lateral motion of the vibrator must be highly restricted while providing relatively free axial displacement of about .+-.0.25 inch.

Abstract: A hammer-type device is driven by a cam and spring arrangement in reciprocating motion to strike a moving train wheel for producing vibrations therein which are used to detect defects in the wheel.

Abstract: A device for testing the fatigue vibration strength consists of a framework carrying a spring-mounted vibrating body, an electromagnetic exciter arranged between the vibrating body and one holding element to hold the test body. There is also an adjustable threaded spindle for the purpose of superimposing a static load on the vibrating load affecting a test body during a vibration strength test. The exciter is provided with two parts which are movable in relation to one another, the one part being connected to the vibrating body and the other to the aforementioned holding element. The two exciter parts are connected to one another by elastic rod shaped members. These are dimensioned in such a manner that in all foreseen operating conditions an air gap remains between the exciter parts permitting vibration excitation with good efficiency.

Abstract: A method and apparatus for improving the power output of a seismic vibrator are provided. Compliant elements with variable stiffnesses are interposed between and connected to the holddown mass and the baseplate. When the compliant elements have a first stiffness, the vibrator-earth system has a first resonant frequency. When the compliant elements have a second stiffness, the vibrator-earth system has a second resonant frequency. During sweep, the compliant elements are set on the first stiffness until the vibrator has passed through the first resonant frequency; then the compliant elements are changed to their second stiffness and the sweep continues through the second resonant frequency.

Abstract: Apparatus for truck-mounting of vibrational seismic energy transducers, particularly shear wave transducers, that provides improved vibrational damping and energy coupling into the earth. The apparatus consists of a four column, hydraulically actuatable suspension system operative from the truck or carrier frame as opposite side pairs to support a box frame under which the vibrator and earth coupling assembly is supported by a system of lateral and vertical springs. The vibrator assembly is entirely supported by means of left and right transverse springs to transmit reactive forces resulting from isolation through the box weldment and four columns to the vehicle body. Thus, the vibrator and its associated base plate structure is entirely supported from the vehicle and positioning assembly by resilient means having the requisite interactive constants.

Abstract: An earthquake simulating machine has a vibrating platform mounted in a frame. The platform is driven by a hydraulic piston which reciprocates the platform through a lever system having a mechanical advantage of about ten to one. The vibration of the platform is isolated from the frame by shock absorbing bushings which support the lever system. Shock absorbing feet may be used to support the frame. The hydraulic piston is controlled by a hydraulic circuit and by an electrical circuit which provides the input to the hydraulic circuit. A feedback circuit monitors the output vibration of the platform.

Abstract: A mechanical complex vibration tester is provided which is capable of simultaneously applying a plurality of discrete frequencies to a workpiece positioned on a test surface of the device to simulate random vibration testing. The vibrations may be varied in amplitude and they may be applied in either the vertical or the horizontal direction. Means are provided for isolating the tester from its environment in order to simulate vibration testing in inertial space.