Design And Study On The Digital Strain Testing System

With the development process of more than half a century, Strain measurement technology has been widely used in various fields of engineering experimental stress analysis. With the great progress of electronic technology, strain measurement devices develop from handwork, to digital display, and then to automate data collection, of displays, printing, disk recording, data transmission and processing of the complete measuring system. The current strain measurement system is toward portable, multi-channel, high precision. Testing software and also becomes professional and convenient.This paper designs and develops a new strain measurement system, a digital multi-channel test system to common strain measurement, including hardware and software systems. The hardware parts include the analog circuit board and its controlling board, Analog-Digital sampling circuit board and the system main board. Responding to the request of multi-point experiments, this strain measurement system can be used in 32-channel testing, which can achieve both static and dynamic strain measurements. This system has the faction of choosing bridge-mode, auto zero and auto magnification options. The system provides the basic functions such as data collection, display and saving. Double-SRAM-model achieves continuous data sampling, and Analog-Digital sampling circuit board transmits the data through the computer bus, which make rapid data transmission and saving.In addition, the software of this tress testing system can do some basic data processing and analysis modules. This makes the strain measurement on the basis of stress calculation, provides intensity calibration, signal analysis, fatigue analysis, and other functions. Meanwhile knowledge-helping module includes the introductions of the using method of this strain testing system and to the knowledge of common strain testing.This paper designs equipment that can produce static stress and periodic vibration stress with the cantilever, with which we verify the strain measurement system. The experiment successfully makes static strain testing and dynamic strain testing of the cantilever. We test the frequency-strain curve and calculate the natural frequency of first order and second order, and it matches the result of the finite element analysis of ANSYS.