1、 Overview of the host

1Function: The high-strength bolt connection pair torsion testing machine for steel structures is mainly used for load testing of high-strength large hexagonal bolt connection pairs and nuts for structural steel. It is also used for testing the tightening axial force and torque coefficient of high-strength bolt connection pairs and nuts for steel structures.

2Applicable standards:

GB/T1231-91High strength large hexagon head bolts, large hexagon nuts, washers and technical specifications for steel structuresGB/T3633-1995Twisted shear high-strength bolt connection pair for steel structures

EN14399-2:2005Pre loaded high-strength bolt connection pair Part 2: Preloading Compliance Test

3The testing machine consists of a host, measurement control system, computer system and software package, functional accessories, and other parts.

2、 The structural composition of the testing machine

【 Main 】 The machine adopts a horizontal structure, and the main structure adopts a welded structure to ensure the rigidity of the whole machine. The fixture is made of high-quality alloy structural steel quenched（HRC50～55）Method: The main drive shaft is treated with alloy structural steel quenching to ensure its service life. Different fixtures can be replaced according to different specimens. The installation and disassembly of the test piece are convenient and fast.

There are various operation buttons on the workbench of the host, which are convenient for users to operate.

The driving system is driven by a fully digital AC servo control system. The characteristics of wide speed adjustment range, uniform and stable loading, and accurate control.

The transmission system adopts a planetary cycloidal pinwheel reducer to ensure uniform, stable and accurate transmission. lateral space0mm～600mmManually adjust within the range. The axial moving part adopts a linear guide pair to eliminate the frictional force generated during bolt loading.

The measurement display system uses a load sensor to collect the axial load of the test boltPHigh precision non-contact dynamic torque sensor collects the torque of the sampleTOptical encoder tests the axial displacement (or angular value) of bolt connection pairs. The computer screen displays the torque of the specimenTAxial loadFTorqueT- Axial loadFCurves, etc. The system can set axial loadF, or torqueTControl the operation and shutdown of the system, and output the following fastening characteristic values:

Torque coefficient of boltsK.

Yield fastening axial forceFfy.

Yield tightening torqueTfy.

Ultimate tightening axial forceFfu.

image2Schematic diagram of experimental apparatus

The extension length generated by the bolt during the loading process, usingLVDTDisplacement sensor testing, this signal is directly input into the computer and processed through relevant data to calculate the corresponding result data.

image3：LVDTdisplacement sensor

【 Software Operation 】 ① The control mode adopts an intelligent expert setting system, and users can customize the test process control mode according to their actual requirements to automatically complete the test. The axial load of the specimen can be setPDetecting torque T, the torque T of the specimen can be set to detect its axial loadPAfter the bolt reaches a certain axial force, it can be rotated to a certain angle, and the elongation of the bolt can also be measured. It can achieve three closed-loop control of torque, axial force, and torsion angle.

② Using computer screen display,WinXPFull Chinese interface, human-machine dialogue mode. All operations of the experiment were carried out with the help ofCRTBy using a computer keyboard and mouse, the test torque is displayed on the computer screenTAxial loadFVarious test curves (force torque curve, force time curve, torque time curve),elongation-Axial force curve, torsion angle-Axial force curve, working status of testing machine, etc. And display the tightening characteristic values of the calculated bolts, etc.

③ Computers collect data in real-time, perform data processing, and provide functions such as data storage, retrieval, statistics, and printing. Real time display, drawing curves, and the ability to zoom in or out of curves.

④ The size of the curve coordinates can be adjusted based on actual experimental data.

⑤ Test report toWordorExcelFormat output.

The experimental process can be simulated and reproduced.

Multiple experimental curves can be overlaid and compared, and output and printed.

Digital zeroing and calibration can be performed.

The experimental data is managed in a database format for easy querying and maintenance.

The operation of the software system can achieve three-level user management, which is safe, convenient, and fast.

[Safety protection system] Overload protection, overcurrent, overvoltage protection, overspeed protection, etc.

3、 Main technical performance indicators

1Maximum torque:30000NmEffective torque range:2％～100％F.S

Torque resolution: ±1/200000(The resolution remains unchanged throughout the entire process)

2Test torque indication error: ±1%

3Test torque repeatability indication error: ≤1%

4Maximum axial load:2500kNRange of axial force measurement:2％～100％F.S

Resolution: ±1/200000(The resolution remains unchanged throughout the entire process)

5Test force indication error: ±1%

6Test force repeatability indication error: ≤1%

7Elongation test: Maximum test travel:10mmAccuracy ±1%

8Effective experimental space: 600mm；（ 0～500mmAny manual adjustment within the range

9Test machine spindle center height: ≥100mm；

10Experimental loading:0.05～3r/minArbitrary setting;

11Rotation angle: minimum reading value0.10Accuracy: ±0.5%

12Adapt to bolt length: ≥200mm

11Voltage Voltage:AC380V 50Hz Motor power15kW

4、 Requirements for the working environment of the testing machine

1At room temperature100C～350CWithin the range, relative humidity ≤80%；

2On a stable foundation or workbench;

3In an environment without vibration or corrosive media around it;

4The fluctuation range of the power supply voltage should not exceed ± of the rated voltage10%.

5、 Configuration of testing machine

1The motor and driver adopt the Yaskawa full digital AC servo control system from Japan

2Load sensor2500kNa

3Dual channel digital data acquisition card（STC8800）One set (self-developed)

4High precision torque sensor30000Nma

5One host (self-developed)

6Fixture: Material40CrNiMoAQuenching（HRC50～55）(Three sets of test fixtures are provided free of charge)

7One Lenovo brand computer: monitor 19Inch LCD

8A set of specialized software for high-strength bolt torsion controlled by a fully Chinese microcomputer

9TheHPOne inkjet printer