Abstract: A method for measuring a behavior of a MEMS device is disclosed. In an embodiment a method includes mounting the MEMS device to a testing apparatus that comprises a vibration source, wherein the MEMS device comprises a 6-axis or 9-axis inertial sensor, applying a vibration to the MEMS device by the vibration source and simultaneously moving the testing apparatus according to a predefined movement pattern, reading output data provided by the inertial sensor and comparing the output data to the predefined movement pattern and/or reading output data provided by the inertial sensor and calculating a frequency response curve of the inertial sensor.

Abstract: The selectable multi-axis shaker table may be adjusted to produce reciprocating linear motion parallel to any one or more of three mutually orthogonal axes, and/or to produce rotary reciprocating motion about its longitudinal axis. The device is driven by a single linear actuator, e.g., a hydraulic or pneumatic ram, linear motor, etc. The device includes a fixed lower base, an intermediate plate adjustably linked to the base, and an upper platform adjustably linked to the intermediate plate. By adjusting one or more of the various linkages between the base, intermediate plate, and upper platform, and/or adjusting the location of the receiver link and linear actuator to the mechanism, the selectable multi-axis shaker table may produce motion of the table platform parallel to its major horizontal axis (X-axis), minor horizontal axis (Y-axis), and/or its vertical axis (Z-axis), and can further produce reciprocating rotary motion of the platform about its X-axis.

Abstract: A microelectronic device tester has a mounting member (for mounting a device), a drive shaft connected to the mounting member, and a vibration shaft mechanically in communication with the drive shaft. The drive shaft and vibration shaft are non-coaxial, and the drive shaft has a drive shaft proximal end and a drive shaft distal end. The drive shaft proximal end is connected to the mounting member, and the drive shaft distal end terminates proximal of the entire vibration shaft.

Abstract: A vibration test apparatus is disclosed. The vibration test apparatus includes a platform assembly, which receives a vibration input from a vibration source and imparts a multi-axial vibration to a test specimen on the platform assembly. In illustrated embodiments the platform assembly includes one or more platforms having an adjustable incline angle. The incline angle is adjusted to provide the desired output vibration based upon a measured or determined vibration profile and the input vibration from the vibration source.

Abstract: In order to provide a vibration testing apparatus which can have a large diameter without introducing undesirable rigid vibration modes, the vibration testing apparatus 1 comprises a support 2, at least one electromagnetic vibration generator 12 mounted on the support, the mounting comprising an annular body 5 and a head expander 10, the annular body being supported by bearings located around the periphery of the annular body 5.

Abstract: A method, apparatus, for subjecting a test object to vibrational energy testing is disclosed. The apparatus comprises a rotatable joint such as a hydrostatic ball joint for transmitting energy from a force generator to the test object, and a support structure, coupled to the test object and the rotatable joint, for flexibly restraining the test object from rotating about the center of rotation of the rotatable joint. In one embodiment of the invention, the support structure comprises a support member and at least one suspension device disposed between the support member and a ground datum. In another embodiment, the suspension device applies a suspension force to the support member in a direction substantially perpendicular to a vector from the center of rotation to the suspending force. In this embodiment the suspension devices are subjected primarily to compression and tension forces.

Abstract: A transducer testing system for low frequency vibrations incorporates an electric motor/gearbox assembly 16 with an output shaft 18 and mechanical means for converting low frequency shaft rotation of the output shaft 18 to uniform low frequency sinusoidal excitation of an accelerometer 10. Simultaneously, a data processing unit 14 measures the response of the accelerometer 10 to the uniform low frequency excitation within predetermined frequency ranges. The data processing unit 14 then compares the measured response with predetermined accelerometer response limits to ascertain whether the accelerometer 10 is functional. The transducer testing system overcomes the limitations of electrodynamic testers to provide a means for accurately testing the low frequency response of the accelerometer 10.

Abstract: A vibrator includes a vibrating table; a plurality of driven unbalanced shafts disposed within the vibrating table and arranged in pairs; and a plurality of unbalanced bodies. A separate unbalanced body is connected to each unbalanced shaft. The unbalanced bodies can assume various vibrating frequencies and angular positions. An adjustment device varies the vibrating frequencies and angular positions of the unbalanced bodies relative to one another. Each shaft is driven by a separate motor; the motors are adapted to rotate in synchronism with one another at a predetermined rotational speed. The adjustment device includes an electronic controller for regulating each of the motors.

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: An apparatus for simulating a rocket launch environment on a test item undergoing centrifuge testing by subjecting the item simultaneously or separately to vibration along an axis of centripetal force and along an axis perpendicular to the centripetal force axis. The apparatus includes a shaker motor supported by centrifuge arms and a right angle fixture pivotally connected to one of the shaker motor mounts. When the shaker motor vibrates along the centripetal force axis, the vibrations are imparted to a first side of the right angle fixture. The vibrations are transmitted 90 degrees around the pivot and are directed to a second side of the right angle fixture which imparts vibrations perpendicular to the centripetal force axis. The test item is in contact with a third side of the right angle fixture and receives both centripetal-force-axis vibrations and perpendicular axis vibrations simultaneously.

Abstract: An inertia force generating device comprises two pairs of coaxial counterrotating eccentric rotors, whose rotational speeds and relative positons are automatically and continuously controlled so as to cancel undesirable vibrations produced by another device. Within each rotor pair, the two rotors have an adjustable angle between their mass centers, so that the effective eccentricity of the pair can be varied, and the phase between the two pairs can also be changed, to alter the direction of the maximum or minimum inertial forces developed. The four rotors include shells of different diameter, nested together on a center plane of the device, or parallel plates configured to maintain a minimum spread of mass centers along the rotational axis.

Abstract: A multiple axis vibration test platform including a plurality of actuator arms connected to respective drive shafts with eccentric ball joints at first ends thereof, and at the opposite ends thereof to the bottom surface and side walls of the test platform with concentric ball joints. The eccentricity of the eccentric ball joint couplings correspond to the amplitude of vibration of the test platform along a respective axis of vibration. The ball joint couplings at each end of the actuator arms eliminate cross coupling of motion between the axes of vibration as the test platform is vibrated simultaneously in more than one axis.

Abstract: An orbital vibratory mass is used for generating seismic signals and the like. An annular reaction mass is mounted on a crank by means of bearing. The reaction mass orbitally oscillates relative to the axis of the crank shaft without rotating. This reduces the internal forces created in the reaction mass by centrifugal force and enables less exotic, less expensive materials to be used in its construction.

Abstract: An abrasion testing machine has a vibrating horizontal platform which supports a six pack of test specimens, such as beverage cans. Hydraulic cylinder controlled pressure plates are applied to the sides of the array of test specimens and to the top of the array as the specimens are vibrated. The amount of pressure is controllable by a control cylinder for each of the pressure cylinders and the speed and magnitude of vibration is adjustable by controlling motor speed and the position of an adjustable linkage between the motor and the platform.

Abstract: A method of determining the phase angle of a vibrating mechanism using line segments of selected angles. The motion of the line segments on the vibration mechanism is observed and the phase angle of the vibratory mechanism is determined using information from the observation.

Abstract: A rotating eccentric weight apparatus and method for generating coded shear wave signals for use in seismic exploration. The apparatus includes a rotatable eccentric and a position sensor capable of detecting each instant that the eccentric passes a particular angular position about its axis of rotation and generating a code signal for use in correlating the raw seismic data obtained. In one embodiment, the apparatus includes an outrigger shovel which transmits a sinusoidal shear wave signal generated by the rotating eccentric while the rest of the apparatus is caused to alternately decouple from and impact against the earth surface to transmit a coded train of pressure wave impulses into the earth.

Abstract: A relatively quiet vibrating screen has a rotatable eccentric mass drive supported on the screen body by isolator mounts which transmit vibratory forces at shaker frequency unrestrained to the screen body and attenuate forces at higher harmonics of shaker frequency that would otherwise excite wall panels of the screen body into resonance, thereby reducing the noise level of the screen.

Abstract: Compact, lightweight, rotating eccentric weight seismic sources and a seismic exploration method particularly suitable for use in relatively inaccessible onshore regions. The source includes an eccentric weight rotatable about an axis and a sensor to detect the instant of peak earthward force developed by the source. A coded energy signal is transmitted into the earth and the seismic waves returned from within the earth are detected. The polarity of a signal proportional to the seismic waves is periodically sampled to produce a plurality of sign-bit samples. The sign-bit samples are automatically shift-summed in response to a code signal generated by the sensor, thereby forming a plurality of shift-summed samples which are recorded to provide a correlated seismic trace.