| Flexible film material has been widely used in biomedical and electrical engineering and other fields, but in practice, the flexible thin film material is often because of their own lack of interfacial mechanical properties such as strength, tensile strength and fracture resulting film peeling failure phenomena. Due to the quality of the mechanical properties of flexible film material directly related to the reliability, stability and lifetime of the device, therefore, in order to enhance the performance of flexible film material components and study the mechanical properties of the flexible film material of great significance. Bulge law a few flexible film can be measured elastic modulus and interfacial bond strength test method mechanical parameters. Advantages of digital speckle that may not be in contact with the measured object can be measured deformable objects with high precision, and can give the audience deformation within the field of view of advantages. In this paper,on the one hand, using digital speckle method and bulge method studies the elastic modulus changes of PVDF membrane material before and after naphthalene sodium treatment.On the other hand, the interface shear strength of flexible and rigid film/substrate structure is also studied.The main research contents and results are as follows.(1) The effects of sodium naphthalene treatment agent on the mechanical properties of PVDF film measured by digital speckle method. On the drum kit gauge, fixed good experimental film, stepping motor drives the hydraulic cylinder oil pressure is applied to the sample film to make it happen bulge deformation, deformation process utilizing digital speckle technique records, according to the relevant formula to calculate the PVDF elastic modulus film distributed between 2.27 ~ 2.61 GPa, experimental results show no significant effect of the treatment agent sodium naphthalene PVDF film modulus of elasticity.(2) The method of digital speckle copper / polyvinylidene fluoride(PVDF) interfacial shear strength of the flexible substrate layered composite film were studied. First of all, the PVDF film is bonded on a steel base with a central hole and completely covers the hole. And then,copper film is bonded on the surface of the PVDF film by slowly solidified epoxy. Finally,make test sample placed in the laboratory instrument.The use of copper and PVDF film substrate between deformation when subjected to external force inconsistent with the characteristics of destruction by applying pressure on the PVDF substrate interface occur until a layered structure. In this way, when you calculate the interfacial shear strength and stability destruction ranged from 40.9-53.2 kPa.(3) Based on the value of the elastic modulus and Poisson’s ratio of copper films and PVDF film material, the use of finite element software Abaqus finite element analysis of the interface between the strain and strain distribution in experimental models and destruction changes, finite element result shows, due to the impediment of rigid film, the level of soft substrate tensile deformation region narrow and focus on the edge of the pressurized area. Flexible film surface position compression shear occurs, this compressive and tensile deformation of rigid film at the shear plane deformation interaction, when the pressure is increased to 1800 kPa shear surface damage has occurred with a large displacement out of the surface.The mechanical properties of the flexible film materials were studied by using digital speckle technique which is a non-contact measuring method in this paper. Experimental results show that digital technology can effectively measure the speckle PVDF film material elastic modulus and copper(Cu) / polyvinylidene fluoride(PVDF) interfacial shear strength of the flexible substrate layered composite film. |
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