Piezoelectric stack direct driving type macro-micro combined biaxial stretching-fatigue testing system

Abstract

The invention relates to a piezoelectric stack direct driving type macro-micro combined biaxial stretching-fatigue testing system, and belongs to the field of precision scientific instruments. The piezoelectric stack direct driving type macro-micro combined biaxial stretching-fatigue testing system is mainly composed of a precision driving-transmission unit, a CCD (Charge Coupled Device) imaging detection unit, a mechanical and deformation signal detection unit, a test piece clamping unit and a piezoelectric stack driver unit. In a testing process, the CCD imaging detection unit is used for carrying out in-situ observation on a central point of a test piece; once the central point is deviated, real-time deviation compensation can be carried out through the large-rigidity and high-frequency response piezoelectric stack driver unit, and a position of the central point of the test piece in the testing process is relatively fixed. The testing system has a wide application range, and can be used for realizing single-axis / double-axis stretching tests and single-axis / double-axis stretching fatigue tests; the testing system has good compatibility with an optical imaging system, and can be used for carrying out correlation rule researches of a microstructure and a deformation damage mechanism of materials.

Description

technical field [0001] The invention relates to a tensile testing device, which can be used for uniaxial / biaxial stretching, uniaxial / biaxial stretching-fatigue material micromechanical property testing platform. The system can be combined with other optical microscopes to dynamically monitor the microstructure evolution behavior and fatigue failure mechanism of the test piece during the test process; through the mechanical and displacement signal detection unit, the tensile and deformation signals of the test piece during the test process can be collected, and finally can be Record the stress-strain history of the specimen under the corresponding load, and then analyze the relevant mechanical properties of the material; through the analysis and processing of the force and deformation signals collected by the mechanical and deformation signal detection unit, combined with the output compensation of the piezoelectric stack, the test system can be realized closed-loop control. ...

AI Technical Summary

Problems solved by technology

[0003] The existing large-scale biaxial tensile testing machine has the advantages of large loading force, large stroke, strong rigidity, and good stability. However, due to volume limitations, the types of compatible imaging devices are limited, and the imaging equipment used in conjunction with them is also relatively expensive. It is difficult to install and clamp small millimeter-scale test pieces. The hydraulic system is used as the driving and loading method, and the control accuracy is low. The test function is mainly concentrated in a single load form, and mechanical performance tests under multi-axial tension / fatigue conditions cannot be performed.

However, the existing commercial biaxial tensile testing device has a large volume, which is not conducive to the integration with the microscopic imaging device, resulting in less research on biaxial tensile in situ testing technology.

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