Shanghai Bilang Brief introduction to the working principle of electronic tensile testing machine.
Electronic tensile testing machine is composed of measuring system, driving system, control system and computer.
1. Control system of tensile testing machine
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. 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 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 port) behind the computer. This technology is relatively mature, reliable, and easy to use.
2. Tensile testing machine measurement system
1. Force value 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 a device that can convert a certain mechanical quantity into electrical output by strain gauges, elastic elements and certain accessories. 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. Take 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 size of 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.
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 change in the output voltage.
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. Measurement of deformation
It is measured by the 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. The encoder will have a pulse signal output. The signal is processed by the processor, and the deformation amount of the sample can be obtained.
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.
3. The driving system of the tensile testing machine
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.
BILON brand, dedicated service
Single Trolley Handle,Luggage Parts For Backpack,Luggage Parts Handle,Adjustable Trolley Bag Handle
GUANGDONG SUNDES LUGGAGE ACCESSORY TECHNOLOGIES CO.,LTD , https://www.sundes-global.com