Test machine knowledge summary

2020-07-16 12:18:37

The test machine knowledge collection has collected some knowledge about the test machine, and I hope it will be helpful to friends who want to understand the test machine. In fact, the use of the test machine is still very wide, and it is really important for everyone.

What is a testing machine dynamometer, tensile machine, vulcanization instrument. The testing machine we usually see should actually be called a material testing machine, and the other is a tensile testing machine. It is an instrument used to test the mechanical and physical properties of various material components.

Overview of the testing machine
1. definition
1.1 Test machine concept and application The test machine is used to measure the mechanical properties, process performance, internal defects and verify the dynamic unbalance of rotating parts under various conditions and environments. Precision test instrument. In the process of research and exploration of new materials, new processes, new technologies and new structures, the testing machine is an indispensable and important testing instrument. Widely used in machinery, metallurgy, petroleum, chemical industry, building materials, construction, aerospace, shipbuilding, transportation, and other industrial departments as well as related laboratories in universities, research institutes. It plays an important role in effectively using materials, improving processes, improving product quality, reducing costs, and ensuring product safety and reliability.

2 Types of testing machines: There are many types of testing machines, and there are many different classification methods. According to the traditional classification method, it can be divided into five categories: metallic material testing machine, non-metallic material testing machine, dynamometer, tensile machine, vulcanization instrument testing machine, vibrating table and nondestructive flaw detector.

1.2.1 Classification of material testing machines: There are many types and models of material testing machines, and their loading methods, structural characteristics, force measuring principles, and use ranges are different.
1.2.1.1 Classification by use: testing machine for measuring mechanical properties and testing machine for process testing 1.2.1.2 Classification by loading method: static load testing machine (static) and dynamic load testing machine (dynamic )
1.2.1.2.1 Static testing machine mainly includes: dynamometer, tensile machine, vulcanization instrument
1.2.1.2.2 Dynamic testing machines mainly include: Fatigue testing machines: dynamic and static universal testing machines, unidirectional pulsating fatigue testing machines, impact testing machines, etc. 1.2.1.3 Classification by force measurement method: mechanical measurement Force testing machine and electronic force testing machine
1.2.1.4 Classification according to control mode: manual control and microcomputer servo control testing machine 1.2.1.5 Classification according to the position of the oil cylinder: upper-mounted and lower-mounted testing machine
1.3 Material test
1.3.1 Mechanical properties of materials: The ability of materials to resist deformation or destruction under the action of external forces is called the mechanical properties of materials. Including strength, plasticity, elasticity, brittleness, fracture toughness, hardness, etc.
1.3.2. Material test: mechanical performance test, physical test, chemical test.
1.3.3 Mechanical properties test of materials: tensile, compression, bending, shear, torsion, impact, fatigue, creep, endurance, relaxation, wear, hardness and other tests.
1.3.3.1 Dynamometer, Tension Machine, Vulcanization Meter, also known as Dynamometer, Tension Machine, Vulcanization Meter, is to slowly apply load on both ends of the sample, so that the working part of the sample is subjected to axial tension, Causes the specimen to elongate in the axial direction, generally until it is broken. The tensile test can determine the tensile strength and plastic properties of the material.

Classification of material testing machines There are many classification methods for material testing machines. Common ones are:
a) According to the type of output source, there are mainly motor, hydraulic, pneumatic, electromagnetic, etc .;
b) According to the indication type at the end of the measurement, there are mainly digital displays and pointers;
c) According to the relationship between the load on the sample and time: static machine and fatigue machine.
d) According to the control mode, there are mainly open-loop control (manual control) and closed-loop control (automatic control). The types of control for closed-loop control are: speed control, load control, deformation control, position control.
e) According to the purpose, there are mainly universal machine dynamometer, tensile machine, vulcanization machine special machine. There are many types of special machines, such as: cement dynamometer, tensile machine, vulcanization instrument, red brick press, wire bending fatigue machine, soft worry machine, electric porcelain bending and twisting machine, horizontal pulling, etc., far balance machine, far triaxial , Vibration table.
f) Test methods and test machines Generally speaking, there are only two types of test machines: the direction of motion (or the direction of force), one is tension, and the other is compression. We usually see tension, compression, bending, shearing, peeling, and tearing. , Wear, wear, etc., this kind of sample.

Detection and control Detection and control are two different concepts, but they are inseparable. Generally speaking, for a specific system, under a specific test condition, it only controls a specific parameter, such as our company's electric pull , It only controls the moving speed of the test bench, and the detection amount is generally more than one, such as electric pull generally has load, displacement, deformation and other detection links.

Fifth, detection binning and control binning detection binning: can improve the sensitivity of the measurement and solve the problem of weighing small objects in large management stations. Control bin: used to solve the problem of precise "positioning", but also solve the problem of measurement accuracy.
Sixth, the relationship between the file magnification and the range division are two different concepts, but they are related to each other. Binning amplification refers to a local parameter of the dynamometer, tension machine, and vulcanizer amplifier, and range binning refers to a characteristic parameter of the testing machine. For the user, the latter has practical meaning, while the former does not require user attention.

7. D / A, A / D converter D / A ---- Digital conversion quantity A / D ---- Analog black heart digital quantity Digital quantity For example: a cup of soybeans, how many beans can you use Count how much it is, but the quantity is always 1, 2, 3, 4, ... n. Analog quantity: For example, a cup of noodles, you can't count how many grains it has, that is to say, you can't separate it one by one, its quantity is continuous. Regarding the concept of "code": original code, inverted code, complement code, ASCâ…¡ Gray code. About the concept of "number system": decimal, binary, hexadecimal, BCD code. Sensor: A device that converts various measurements into electrical signals.
1. Common sensors: load sensor, deformation gauge, displacement sensor, pressure sensor, temperature sensor (thermocouple, thermal resistance, semiconductor temperature sensor) differential pressure sensor, gilt sensor, etc. 2. Piezoelectric crystal load sensor, grating, magnetic grid, dynamometer, tensile machine, vulcanization instrument (incremental, absolute), etc. It is an analog sensor in front operation and a digital sensor in rear operation. According to the measurement material, it is divided into: metal testing machine, non-metal testing machine. According to the function is divided into: dynamometer, tensile machine, vulcanization instrument, universal testing machine, impact testing machine, etc.

A testing machine, broadly speaking, is an instrument that verifies the quality or performance of a product or material according to design requirements before it is put into use. From the definition, it can be seen that any instrument that verifies quality or performance can be called a testing machine, but it is often called a tester, tester, tensile machine, testing equipment, tester, and so on. In the textile industry, it is used to be called a strong machine, which is actually a tensile testing machine. The testing machine is mainly used to measure the physical properties of materials or products, such as: the yield strength and tensile strength of steel, the hydrostatic time measurement of pipes, and the fatigue life of doors and windows.

The testing machine is divided into two categories: "performance testing machine" and "environmental testing machine".

(1) Performance testing machine

a. The functional testing machine simulates the actual function of the product through the testing machine, and obtains the test data, such as the maximum traction force, braking force, maximum speed of the car, the switching force of the door and window, the fatigue life of the switch, etc., and the maximum withstand pressure of the electrical switch. Such as the spring tension and compression test machine to check the performance of the spring, the door and window mechanical property test machine to detect the life of the door and window, the microcomputer control pipe pressure burst testing machine to detect the service life of the aluminum-plastic composite pipe, and the microcomputer control valve test to test the valve and the water nozzle machine. A furniture testing machine that simulates the use of furniture, a switch and socket testing machine that simulates the use of switches and sockets, etc.

b. Structural mechanics testing machine is generally used for mechanical and mechanical performance test of products that bear dynamic and static loads. Simulate the state of external forces during the test, such as tension, pressure, torsion, vibration, impact, bumps, drops, etc., and perform static and dynamic tests. During the test, it is often added to the specified load value, loading time or until the structure is destroyed to determine its strength, to verify the correctness of the product design and parameter calculation. Such as steel, plastics, etc., computer-controlled electronic universal testing machine for strength test, microcomputer-controlled electronic universal testing machine for flattening test of PVC, PPR and other non-metallic tubes or composite tubes, automatic impact for PVC pipe impact Hammer impact testing machine, etc.

(2) The best environmental test of environmental testing machine is definitely natural exposure test and field test, but the test cost is higher, the time is longer, the repeatability and regularity of the test are poor, so artificial simulation environmental test is widely used, That is, an environmental testing machine is used. The main environmental testing machines are as follows: a. Aging testing machine

b. Damp heat testing machine is divided into: constant temperature and humidity testing machine, alternating damp heat testing machine, normal temperature damp heat testing machine

c. Temperature impact testing machine such as: pipe cooling and heating cycle testing machine

d. Pressure impact testing machine such as: pipe pressure cycle testing machine

e. Smoke testing machine

f. Seal testing machine

g. Low pressure testing machine

h. Mold testing machine

i. Anti-corrosion testing machine

j. External force testing machine such as fully automatic drop weight impact testing machine, door and window mechanical property testing machine, connector tension and pressure testing machine

k. High and low temperature testing machine

2. For the mechanical performance test, it can be divided into dynamic testing machine and static testing machine

(1) Dynamic testing machine: Long-term test of the sample at a certain frequency according to the required waveform until a certain time or the sample breaks. Such as high frequency fatigue testing machine, low cycle fatigue testing machine, etc.

(2) Static testing machine: apply force to the sample at a uniform speed until the sample breaks. Such as universal testing machine, pressure testing machine, etc.

3. According to the way of use, it can be divided into online testing machine and non-online testing machine

(1) The on-line testing and testing machine is used in the production equipment to know some physical properties of the product during the production process. For example, the pipe pressure blasting test machine in the steel pipe production line, the last production process is to fill the steel pipe with water to make a compression test.

(2) Most of the test equipment of the non-online testing and testing machine is working in the laboratory, and all belong to the non-online testing and testing machine.
Fourth, according to the force mode, it can be divided into single-axis and multi-axis testing machines

(1) Uniaxial testing machine: A test in which a sample is subjected to a force in only one direction. All universal testing machines belong to uniaxial testing machines, torsion testing machines, fatigue testing machines, etc.

(2) Multi-axis testing machine: The test is performed not only when the sample receives a force in one direction. Such as: rock and soil mechanics testing machine, seismic simulation test bench, tensile and torsional composite testing machine, bending and torsional composite testing machine, etc.

5. According to whether the sample is damaged during the test, it can be divided into non-destructive testing machine and non-destructive testing machine.

(1) A non-destructive testing machine is a test machine that obtains test data by not destroying the sample during the test. Such as: hardness tester, flaw detector, etc.

(2) A testing machine that obtains test data through a destructive test. All universal testing machines and pressure testing machines are classified as destructive testing machines.

6. Classification according to usage mode According to the usage mode, it can also be divided into online testing and testing machines and non-online testing and testing machines:
1. The on-line testing and testing machine is used in the production equipment, and certain physical properties of the product can be known during the production process. For example, the pipe pressure blasting test machine in the steel pipe production line, the last production process is to fill the steel pipe with water to make a compression test.
2. Most of the test equipment of the non-online testing and testing machine is working in the laboratory, and all belong to the non-online testing and testing machine.

It is used to determine the mechanical properties, technological properties, physical and chemical properties, anti-vibration properties, etc. of various materials under different conditions. The amount of dynamic imbalance.

There are many types of test machines, there are many different classification methods, it is not necessary to list them one by one.

According to the traditional classification method, it can be divided into five categories: metal material testing machine, non-metallic material testing machine, dynamic balance testing machine, vibrating table and nondestructive testing machine.

Classified according to loading method: static load testing machine (static) and dynamic load testing machine (dynamic).

Static testing machine mainly includes: universal testing machine, pressure testing machine, tensile testing machine, torsion testing machine, creep testing machine.

Dynamic testing machines mainly include: fatigue testing machines: dynamic and static universal testing machines, unidirectional pulsating fatigue testing machines, impact testing machines, etc.

Static load: apply a steady and increasing load to the sample until it reaches the specified requirements.

Dynamic load: Impact, repetitive, alternating and random dynamic loads are applied to the sample until it reaches the specified requirements

Classification by use: testing machines for measuring mechanical properties and testing machines for process tests, packaging testing machines, automotive testing instruments, force and weight, length reference measuring instruments, various testing machine accessories (fixtures, environmental boxes).

From the nature of application, it is mainly divided into two categories: "performance testing machine" and "environmental testing machine".

According to the type of output source, there are several types of motor, hydraulic, pneumatic, electromagnetic, etc.

According to the indication type at the end of the measurement, there are mainly digital display and pointer

According to the relationship between the load on the sample and the time: the static machine and the fatigue machine

According to the control mode, there are mainly open-loop control (manual control) and closed-loop control (automatic control). The types of control for the closed-loop control are: speed control, load control, deformation control, position control.

Test methods and test machines Generally speaking, there are only two types of test machines: the direction of motion (or the direction of force), one is pulling, and the other is pressing. We usually see pulling, pressing, bending, shearing, peeling, tearing, wearing , Wear, etc., this kind of sample.

According to usage, there are general-purpose machine (universal machine) and special machine.

The transmission mode of the testing machine: mechanical transmission, electrical transmission, pneumatic transmission and hydraulic transmission.

3. Features of testing machine:

1. Many varieties, small quantity, measuring instruments, high-tech products (with high quality requirements and wide range as the industry develops)

2. In addition to longitudinal, two-dimensional and three-dimensional testing

3. Temperature environment simulation, (simulation develops towards real, real and slight)

4. Testing machine control technology

Testing machine technology is a comprehensive technology, which covers a variety of fields. Sometimes the seemingly simple test is actually very knowledgeable in the test method and interpretation of the analysis results. The laboratory and modernization industry of materials and structural parts is an important issue. She has great significance for improving the comprehensive quality of products, and is also indispensable for the research and development of new materials and new structures. In short, test technology requires long-term knowledge and experience accumulation, which cannot be achieved overnight. Committed to the research and discussion of test technology, and the promotion of the application of new technologies, will undoubtedly make a lot of contributions to China's test machine.

1. Acquisition and measurement

Processing signals from different types of sensors is not a simple technique. The control system is particularly important in the special application of the testing machine field, and on the other hand, it meets the data acquisition requirements of all general inspection fields. At the same time, the unique technology must be mastered in the digital interface. Make the control function permanently depend on the control of the measured result of the controlled variable.

1) Analog signal measurement

The carrier frequency amplifier has a digital-to-analog converter, which is particularly suitable for static testing machines and low-frequency dynamic detection applications. Its core is the voltage / frequency (voltage / frequency) conversion technology.

The voltage (analog) signal of the sensor is continuously converted into a frequency signal. Therefore, there is a direct proportional relationship between its frequency and voltage. The resolution of the analog-to-digital conversion depends on the length of the frequency count, which is called the integration time. The signal conversion and amplification process is cyclically processed at equal intervals from negative to zero crossing to positive. The high-resolution conversion and amplification technology has great advantages, so not only does the sensor not need to be divided; but more importantly, its same high resolution exists in the entire range of the sensor. And its advantages are particularly obvious when approaching the sensor's rating. In actual measurement, analog sensors (such as strain bridge load sensors or extensometers) can observe small changes in high-resolution measured values â€‹â€‹even when they are close to the rated value of the range. The measured value corresponds to the linkage result of different integration time, refresh time and resolution. Under the premise of fully understanding the interaction between several people, specific combinations can be made according to the test requirements in order to obtain the best results. Under the premise of the coordination of computer capabilities, the faster the control, the higher the resolution of the digital display.

Another factor to consider is the system filtering time delay. This time delay will naturally be integrated into the measured value. For example, under the integration time of 5 ms, the 4ETF acquisition module of German EDC has a total delay time of 6.7 ms. Dolly's 4ETF module has a resolution of 280,000 yards with an integration time of 20 milliseconds, and its linearity error is 0.01%.

2) Digital signal measurement

Digital incremental sensors use several different operating principles. The most common are optical or electromagnetic sensors. Which type to choose in a specific application depends on the use itself, accuracy requirements, and environmental factors such as temperature and pollution.

Main types

Rotary encoder, linear displacement sensor.

Reference datum

Basically, the digital incremental sensor is a relative measurement system; in other words, people do not know the absolute position of the measuring head when starting the measurement. In order to accurately determine the absolute position of the measuring head, most measuring systems are equipped with reference datums. Rotary encoders have a reference datum per revolution, while linear sensors usually have one or more reference datums.

Supply voltage

In industry, the 5V supply voltage is most commonly used. Of course, variable supply bridge voltages, such as between 11V and 32V, are also common. The advantage of this type of sensor is that it can be directly connected to the power supply of the vehicle.

Principle of signal transmission

The measuring head with three sensors moves linearly along the barcode. These barcodes excite the sensors to generate signals.

Signal waveform

Sine and long square waves

Common simple sensors generally produce rectangular waveforms; however, high-grade digital incremental sensors often use sinusoidal waveforms. Some sensors also have analog multipliers; in this mode, the signal output is the number of long square wave pulses per sine cycle (the number of pulses depends on the multiplier).

3) Control output

General implementing components include: solenoid valves, frequency converters, motor drives, etc.

Electric pull machine, used with power amplifier to control DC motor.

Electric pull machine, with any power amplifier, can provide Â± 10V or digital command control signal, all necessary control signals of external power amplifier can be provided by the controller.

Hydraulic machine, valve drive of Â± 10V.

Hydraulic machine drives servo valve.

Dynamic machines, driving pneumatic / hydraulic servo valves or linear motors.

More load sensors, LVDTs, load sensors, strain extensometers, long-range dual-channel photoelectric extensometers, serial extensometers, safety screens, more IO ports, and several EDC applications in multi-channel control.

2. Host computer software

It is a specially developed program package that integrates all operations of the testing machine into the computer management. Using this program combination can greatly simplify the connection between the client's host computer and the control system, and even the entire debugging process including the calibration process. Used to help customers in online debugging, testing, data analysis reports.

1. Definition:

2. Type: