Relaxation Testing Machine

Computer-controlled steel strand relaxation testing machine: primarily used for testing relaxation characteristics of steel strands and other prestressed metal materials, and can also perform conventional static tensile tests on ordinary steel samples. The machine applies mechanical loading, with the entire test process controlled by computer. The PC performs real-time data acquisition, display, and automatic processing, automatically plots the relaxation force curve, and monitors the test in real time. The SL series computer-controlled steel strand relaxation testing machine is suitable for testing samples with the minimum length specified in national standards, while the SL-W series is suitable for relatively longer samples (>2m). The product is designed and manufactured according to GB/T 16491—2008 "Electronic Universal Testing Machines," GB/T 2611 "General Technical Requirements for Testing Machines," and GB/T 6825.1-2002 "Verification of Static Uniaxial Testing Machines - Part 1: Verification and Calibration of Force-Measuring Systems for Tensile and/or Compressive Testing Machines." The complete machine consists of a main unit, a computer control and measurement system, and other components.

■ Meets the requirements for "stress relaxation properties test" specified in (GB/T5224-2014) "Steel Strand for Prestressed Concrete" and complies with the provisions of (GB/T10120-2013) "Metal Stress Relaxation Test Method".

■ Equipped with two control channels for test force and displacement, as well as multiple corresponding control methods such as test force, stress, and displacement, allowing free switching between control modes; PID control parameters can be adjusted online.

■ The initial test force can be automatically and accurately applied uniformly at the specified rate. Other tests including constant rate of test force, constant rate of stress, constant rate of displacement, as well as constant test force, constant stress, and constant displacement tests can also be performed, with continuously adjustable loading rates.

■ Automatically collects, processes, and displays test data, and automatically measures various characteristic points of the tested material.

■ Automatically draws the relaxation force-time curve and automatically adjusts the coordinates to always display the instantaneous or complete curve. It can also automatically generate various test curves such as force-displacement, force-time, and displacement-time, automatically edit test reports, and print outputs in real time.

■ Automatically performs temperature measurement and plots the temperature-time curve.

■ Constant displacement control can still be performed during the stress relaxation test, maintaining the initial total strain or gauge length constant, fully complying with national standards.

■ The test duration can exceed 1,000 hours, allowing extrapolation of test data—for example, predicting 1,000-hour stress relaxation performance based on 100-hour results. A spoke-type (reinforced elastomer) load sensor is used, better meeting the requirements of long-duration testing.

■ Features automatic zero adjustment, automatic calibration, and other functions. Allows input of original test parameters. Test results are automatically stored and can be reviewed at any time.

■ Equipped with a powerful database and multiple interface formats for users to choose from, helping users achieve local network communication.

■ Equipped with multiple protection measures such as overload, overcurrent, and limit protection.

In addition to testing the relaxation properties of steel strands, it can also test the relaxation properties of steel bars, and perform conventional static tensile tests on ordinary steel samples.

■Reaction frames can be configured according to user requirements for testing the machine using pressure sensors. An emergency power supply can also be configured to prevent data loss due to unexpected power outages.

Technical Parameters of Microcomputer-controlled Steel Strand Relaxation Testing Machine: