SU940075A1 - Stand for impact accelerometer dynamic graduation - Google Patents

Description

() STAND FOR DYNAMIC CALIBRATION OF IMPACT ACCELEROMETERS

one

The device relates to a measurement technique, namely a technique, measurement of impact parameters.

Devices for dynamic calibration of shock accelerometers by the force measurement method are known, containing a hammer, on the end of which a graduated accelerometer is rigidly fixed, and the other end is made in the form of a sphere of large radius, a guide device, an anvil and a measurement system l.

The maximum contact force, the shock acceleration and the duration of the shock pulse depend on the radius of the sphere of the striking part, the height of the fall and the mass of the impactor. Such a device has a low accuracy due to the presence of local plastic deformations in the contact zone of the colliding bodies and the lack of accounting for them in the calculated ratios. In addition, the device does not allow the reproduction of shock pulses with a duration of more than one millisecond.

The closest to the proposed technical essence and the achieved effect is a stand for calibration of shock accelerometers, containing a drummer with a graduated accelerometer rigidly attached to the end, a guide and braking device, an anvil made in the form of a force sensor, the outputs of a shock accelerometer and a force sensor through preliminary amplifiers and peak voltmeters are connected to a two-beam electronic oscilloscope. The grading is based on the use of the Newton's C2j Second Law.

Claims (1)

The device also has insufficient accuracy due to the lack of control over the correctness of the strike. In addition, the force sensor is connected to the anvil through the transition elements, which distorts its display. The purpose of the invention is to increase the accuracy of the dynamic grading 1 and impact accelerometers by monitoring the accuracy of the impact and improving the accuracy of the force measurement. The goal is achieved in that the stand containing a drummer with fastening elements of a graduated accelerometer, a guide and braking devices, an anvil made in the form of a force sensor, an accelerometer amplifier connected via a voltmeter to an oscilloscope, and a force sensor amplifier are entered placed in the drummer, a force sensor amplifier and a comparison unit, the inputs of which are connected to the outputs of the amplifiers of the force sensors, and the output is connected via a voltmeter to an oscilloscope. In addition, the drummer and the anvil are completed in the form of magnetoelastic throttle force sensors. The drawing shows the device. The device consists of a calibrated accelerometer T, which is rigidly fixed on the end face of the impactor 2 placed in the guide device 3. At the other end of the impactor, there is an element of the braking device k, another element of which is located on the end of the anvil 5. Placed in the holes 6 the anvils, the winding 7 and in the holes 8 of the striker the winding 9 connected in the circuit of the voltage source (Sne (shown)), respectively, form an magnetoelastic choke force sensors with the anvil and the striker. The graduated shock accelerometer and windings 7 and 9 are connected to the information processing system 10. The outputs of the windings 7 and 9 through the preamplifiers 11 are connected to the inputs of the comparison unit 12. The outputs of the preamplifier 13 of the shock accelerometer and of the block 12 are connected via peak voltmeters I to a two-beam electronic oscilloscope 15. The device works as follows. The graduated accelerometer, together with the drummer, is released from the locking device (not shown) and begins to move in the guiding device under the force of the earth's attraction before the impact through the elements of the braking device with the hammer. The change in the magnetic flux in the impactor and the anvil is proportional to the magnitude of the contact force arising in the process of their collision. An electrical signal proportional to the magnitude of the change in contact force over time from windings 7 and 9 is fed through preamplifiers to a comparison unit, in which the signals from the windings are compared and, if their absolute values are equal, an electrical signal appears at the output of the comparison unit. An electric signal proportional to the acceleration from the calibrated shock accelerometer through the pre-amplifier 13 and the peak voltmeter 1 is fed to the first input of the oscilloscope. To the second input of which, through a peak voltmeter 1, an electric signal is received, which is proportional to the contact force during a collision, from the output of the reference unit. The oscilloscope monitors the shape of the shock pulse reproduced when the impactor strikes the anvil. The magnitude of the shock acceleration is determined by the formula 3 where A is the shock acceleration; P - contact force; m is the mass of the remote control and shock accelerometer. The sensitivity of the shock accelerometer can be determined directly from the scaler preamplifier of the shock accelerometer, adjusting its gain so that the indications of peak voltmeters measuring signals from the force sensor and the shock accelerometer are the same. It is possible to expand the operational capabilities of the device for dynamically calibrating shock accelerometers by lengthening the direction of its device, applying pre-accelerator devices with a graduated shock accelerometer, using interchangeable braking devices ensuring the formation of shock pulses of different shape and basic parameters. Claim 1. Stand for dynamic calibration of shock accelerometers, containing