JPS5977336A - Device for measuring impact for high speed load tester - Google Patents

Abstract

PURPOSE:To compute the impact generated at a punch, by attaching a load detecting sensor and an inertial force detecting sensor, and making the natural frequency of the inertial force detecting sensor agree with the natural frequency of the load detecting sensor including the punch. CONSTITUTION:At the tip of a piston rod 1, an inertial force detecting sensor 5, a load detecting sensor 4, and a punch 3, which is fixed to the load sensing part of the load detecting sensor 4, are attached. A weight is fixed to the load sensing part of the inertial force detecting sensor 5, and the natural frequency of the sensor 5 is made to agree with that of the load detecting sensor 4. Therefore the phase difference between the outputs of both sensors is removed. A resultant force Fo is based on an impact Fs, which is detected by the load detecting sensor 4, and an inertial force Falpha. The inertial force Falpha is obtained by correcting an inertial force F'alpha, which is detected by the inetial force detecting sensor 5. The inertial force Falpha is subtracted from the resultant force Fo, and only the output waveform Fs can be computed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an impact force measuring device in a high speed load testing machine.

Generally, in high-speed load testing machines, impact force is generated by impacting the test object with a punch at a predetermined high speed, for example, 1 m/sec to 20 m/sec, and the impact breaking load and its energy are measured on the test object. do. In conventional devices, the impact force was measured by letting the punch fall naturally from a predetermined height via a rope, pulley, etc., and calculating the energy from the weight of the punch and its height. In this method, it is difficult to determine how the specimen under test will be destroyed instantaneously, how the load will be applied,
The actual energy and other information were unknown, and it was not possible to obtain sufficient data to satisfy the requirements.

A possible solution would be to incorporate a load cell into the punch and instrument it to measure the impact force, but the load cell would detect the inertia force caused by the acceleration acting on the punch, and the test object would The object of the present invention is to provide an impact force measurement device that can separate and detect the true impact force that acts on a test object due to the impact of a punch. It is in.

The present invention is characterized in that a load detection sensor that detects the force acting on the punch is fixed to the punch that is collided with the test object, and an inertia sensor that moves with the bonder and detects the inertial force that acts on the punch. A force detection sensor is installed,
By making the natural frequency of the inertial force detection sensor almost equal to the natural frequency of the load detection sensor including the punch, the phase difference between the outputs of each other is eliminated, and the inertia of the punch is determined from the detected value of the force acting on the punch. The structure is such that it is possible to subtract the detected force value, thereby detecting only the impact force acting on the punch, δ1t.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention,
FIG. 2 is a sectional view of the main part of the punch section 2.

The bonding section 2 installed at the tip of the piston rod 1 of the high-speed load testing machine detects the punch 3 that directly collides with the test object and the force acting on the punch 3 by fixing the punch 3 to a load sensing section. It is comprised of a load cell 4 for detecting an inertial force, an inertial force detection load cell 5 for detecting its own inertial force caused by the acceleration of the punch section 2, and the like. Load cell 5 for inertial force detection
In order to match the natural frequency of the 1-coat cell 5 for inertial force detection with the natural frequency of the load cell 4 to which the punch 3 is fixed, and to eliminate the phase difference between their outputs,
A weight 5a is fixed. This weight 5a can be changed according to the punch 3 that is changed depending on the test. The output of the load cell 4 and the output of the inertial force detection load cell 5 are guided to a rotary amplifier 6 and an inertial force load amplifier 7 by an output cable 2ε, amplified, and then introduced into the calculation unit 8. In the calculation unit 8, the output Fα' of the inertial force amplifier 7 is multiplied by an inertial force correction mass factor M, which will be described later, to obtain Fα' ・M−Fα, and the value Fα is calculated from the output F' g of the load amplifier 6. Subtract F
s-Fo -Fα is calculated and output, and the output Fs is introduced into the transient memory 9 and stored.

Next, we will discuss the effect. When the screw 1 of the test machine is driven at high speed and the punch 3 collides with the test object, the rotor amplifier 4 to which the punch 3 is fixed detects the impact force Fs due to the collision, and also detects the acceleration during starting and stopping. Depending on α, if the 1R amount of punch 3 and load cell 4 is m, then ■? α-m・
Detect the inertial force α, and the resultant force of these forces FD=FS+
Fα is output from the load amplifier 6. On the other hand, the inertial force detection load cell 5 detects an inertial force Fα'=m' ・α by the acceleration α acting in the same manner, where m' is the mass of the weight 5a and the inertial force detection load cell 5. ,
It is output from the rotor amplifier 7 for inertial force. This inertial force Fα
' is multiplied by the inertial force correction mass factor M set to the value M=m/m' in the calculation unit 8 and becomes Fα.
and is subtracted from the output F[1 of the load amplifier 6 described above. Therefore, the output from the calculation unit 8 is the resultant force FD of the impact force p5 from the load amplifier 6 and the 11"i force Fα.
From this, only the impact force Fs, which is the value obtained by subtracting the inertial force Fα, is left. In this way, the natural frequencies of the load cell 4 and the load cell 5 for detecting inertial force are made to match to eliminate the phase difference between their outputs, and the output waveform of the resultant force of the impact force and inertial force detected by the load cell 4 is , the inertial force component is removed, and the output waveform of the impact force (h) is stored in the transient memory 9.

As explained above, according to the present invention, it is possible to separate only the impact force acting on the punch and detect its waveform. Destruction energy and other information can be determined, and data that could not be collected using conventional equipment can be obtained.

In addition, in the above-mentioned embodiment, the present invention can also be subjected to a drop test if the punch is configured to fall naturally, and furthermore, if applied to the hammer part of a Charpy tester, an impact force of 6 J can be applied to the Charpy test. Waveforms can be extracted.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a sectional view of the main part of the punch section. 1 - Piston rod 2 - Punch part 3 - Punch 4 - Roto amplifier 5 - Load cell 5a for inertial force detection - Weight 6 - Load amplifier 7 Load amplifier for inertial force 8 - Computing unit Patent applicant Shimadzu Corporation Agent Patent Attorney Nishi 1) Arata

Claims (1)

[Claims] A punch that collides with the test object at a predetermined speed to generate an impact force, a load detection sensor attached to the punch that detects the force acting on the punch, and the natural frequency of the load detection sensor including the punch. an inertial force detection sensor that is adjusted to have approximately equal natural frequencies and that moves together with the punch and detects an inertial force that acts on the punch;
fi for a high-speed load testing machine, comprising means for calculating the impact force generated by the punch by subtracting the inertial force detected by the inertial force detecting sensor from the force detected by the load detecting sensor;
Impact measurement device.