Dynamic strain measurement method for drawing mechanical property tests of film material

Abstract

The invention discloses a dynamic strain measurement method for drawing mechanical property tests of a film material. The method comprises the following steps: rectangular grid drawing; camera positioning; shooting sampling; extraction of grid nodes; calculation of 3D coordinates of the nodes and reconstruction of grid point cloud; division of a triangular unit; calculation of side length of the triangular unit; strain calculation. According to the operation steps, dynamic full-field strain distribution information of the film material in uniaxial drawing and biaxial drawing mechanical property tests can be measured, deformation rules of the film material can be obtained precisely, mechanical properties of the film material can be mastered accurately, important material parameters are provided for design and analysis of a film structure, and design precision and use safety of the film structure are guaranteed. The dynamic strain measurement method has the advantages of being non-contact, non-damage, simple to operate, high in automation degree, efficiency and measurement precision, low in cost and the like.

Description

technical field [0001] The invention belongs to the field of measurement technology and building material test technology, and in particular relates to a method for measuring dynamic strain in a tensile mechanical property test of membrane materials. Background technique [0002] Membrane material is an emerging structural material, mainly including thermoplastic film, coated fabric film and laminated fabric film, etc. It has the advantages of light transmission, light weight, high strength, durability, heat resistance, insulation, etc., and is widely used It is used in the fields of modern building structures and industrial fields such as aviation and aerospace, such as the main constituent materials of architectural membrane structures, aviation airships, superpressure balloons, aerospace parachutes or soft landing systems. However, the mechanical properties of membrane materials are relatively complex, and they often show material nonlinearity, time-varying properties, in...

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Problems solved by technology

[0006] In order to overcome the deficiencies in the existing dynamic strain measurement methods of tensile deformation of membrane materials and meet the requirements of efficiency, accuracy, dynamics, size and cost in the actual test measurement process, the invention provides a membrane material tensile mechanical performance test The dynamic strain distribution measurement method can be applied to the dynamic full-field strain distribution measurement of the uniaxial and biaxial tensile mechanical performance tests of thermoplastic polymer films, coated fabric films and laminated fabric films, etc., to obtain high-precision measurement result

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