Tensile machine material testing machine, universal testing machine The electronic tensile testing machine is a product of the combination of modern electronic technology and mechanical transmission technology. It is a large-scale precision testing instrument that fully utilizes the advantages of electromechanics and can perform various performance tests on various materials such as tension, compression and bending , And has the characteristics of wide measurement range, high accuracy and fast response. Reliable work, high efficiency, real-time display recording and printing of test data. Electronic tension machine is composed of measuring system, driving system, control system, and computer. 1. Measuring system 1. Force measurement The measurement is carried out by load cells, amplifiers and data processing systems. The most commonly used load cells are strain gauge sensors. The so-called strain gauge sensor is composed of strain gauges, elastic elements and some accessories (compensation elements, protective covers, wiring sockets, loading parts), which can turn a certain mechanical quantity into a power output device. There are many types of strain gauge tension and pressure sensors at home and abroad, mainly including cylindrical force sensors, spoke force sensors, S double-connected hole sensors, cross beam sensors and other types. It is known from the mechanics of materials that under small deformation conditions, the strain ε of a certain point of an elastic element is proportional to the force received by the elastic element, and also proportional to the elastic deformation. Taking the S-type sensor as an example, when the sensor is subjected to the tensile force P, the strain gauge is attached to the surface of the elastic element. Because the strain of the elastic element is proportional to the external force P, the strain gauge is connected to the measurement circuit. By measuring its output voltage, the magnitude of the force is measured. For the sensor, the differential full-bridge measurement is generally used, that is, the attached strain gauges form a bridge circuit. R1, R2, R3, R4 are actually 4 (or 8) strain gauges with equal resistance, ie R1 = R2 = R3 = R4, when the sensor is subjected to external force (tensile force or pressure), the elastic element of the sensor produces strain The resistance values ​​are changed, and the change values ​​are △ R1 △, R2, △ R3, △ R4. As a result, the originally balanced bridge is now unbalanced, and the bridge circuit has a voltage output. Set △ E Then △ E = [R1R2 / （R1 + R2） 2] △ R1 / R1- △ R2 / R2 + △ R3 / R3- △ R4 / R4) U Where U is the voltage of the external power supply bridge Further reduced △ E = [R2 / 4R2] (△ R1 / R- △ R2 / R + △ R3 / R- △ R4 / R) U Substitute △ Ri / Ri = Kεi into the above formula Then △ E = [UK / 4] (ε1-ε2 + ε3-ε4) To put it simply, the external force P causes the deformation of the strain gauge in the sensor, resulting in the imbalance of the bridge, which causes the sensor output voltage to change. We can know the magnitude of the force by measuring the output voltage change. In general, the output signal of the sensor is very weak, usually only a few mV, if we directly measure this signal, it is very difficult, and can not meet the requirements of high-precision measurement. Therefore, the weak signal must be amplified by an amplifier. The amplified signal voltage can reach 10V. The signal at this time is an analog signal. This analog signal is converted into a digital signal through a multi-way switch and an A / D conversion chip, and then data processing is performed. At this point, the force measurement comes to an end. 2. Deformation measurement It is measured by a deformation measuring device, which is used to measure the deformation of the sample during the test. The device has two chucks, which are connected to the photoelectric encoder installed on the top of the measuring device through a series of transmission mechanisms. When the distance between the two chucks changes, the shaft of the photoelectric encoder is driven to rotate, and the photoelectric encoder There will be a pulse signal output. Then the single-chip microcomputer processes this signal to get the deformation of the sample. 3 Measurement of beam displacement The principle is roughly the same as the deformation measurement, and the displacement of the beam is obtained by measuring the output pulse number of the photoelectric encoder. 2. Drive System It is mainly used for the movement of the beam of the testing machine. Its working principle is that the motor is controlled by the servo system. The motor drives the screw to rotate through a series of transmission mechanisms such as the reduction box, so as to achieve the purpose of controlling the movement of the beam. By changing the speed of the motor, the moving speed of the beam can be changed. 3. Control system As the name implies, it is a system that controls the operation of the testing machine. People can control the operation of the testing machine through the console, and the status of the testing machine and various test parameters can be learned through the display screen. If the machine is equipped with a computer, the computer can also realize each And perform data processing analysis and test result printing. The communication between the test machine and the computer generally uses the RS232 serial communication method. It communicates through the serial port (COM number) behind the computer. This technology is relatively mature, reliable, and easy to use. 4. Computer It is used to collect and analyze data. After entering the test interface, the computer will continuously collect all kinds of test data, draw test curves in real time, and automatically find each test parameter and output report. 14Pcs Knife Block Set,Abs Handle Knife,14Pcs Knife Set,Bamboo Wooden Knife Set YANGJIANG SHENGJIA TRADING CO., LTD. , https://www.yjkitchenknife.com