基于数字散斑法的柔性薄膜力学性能测试研究

发布时间：2019-04-20 15:25

【摘要】：柔性薄膜材料在生物医学和电子工程等领域有着广泛地应用,然而在实际应用中,柔性薄膜材料经常会因本身界面结合强度、抗拉强度等力学性能不足,造成薄膜的断裂和剥离等失效现象。由于柔性薄膜材料的力学性能好坏直接关系到元件的可靠性、稳定性及寿命,因此,为了提升柔性薄膜材料元器件的使用性能而研究柔性薄膜材料的力学性能有着重要的意义。鼓包法是可以测量柔性薄膜材料弹性模量和界面结合强度等力学参数的实验方法。数字散斑的优点在于可以不和测量物体接触就可以测出物体的变形,具有精度高,并可以给出视野范围内的全场变形等优点。本文将数字散斑方法和鼓包法结合起来,研究了萘钠处理剂对PVDF柔性薄膜材料弹性模量的影响,以及硬质薄膜/柔性基底结构的界面剪切强度。主要研究内容及结果如下:(1)采用数字散斑方法研究了萘钠处理剂对PVDF薄膜力学性能的影响。在鼓包测量仪上,安装固定好实验薄膜,利用步进电机驱动油压缸将油压施加在样品薄膜上使其发生鼓包变形,利用数字散斑技术记录下变形过程,根据相关公式计算出PVDF薄膜的弹性模量分布在2.27~2.61 GPa之间,实验结果表明萘钠处理剂对PVDF薄膜的弹性模量并无显著影响。(2)采用数字散斑方法对铜/聚偏氟乙烯(PVDF)基底柔性层状复合薄膜的界面剪切强度进行了研究。首先将PVDF薄膜粘结在有中心孔的钢制基座上并完全覆盖中心通油孔,之后将制作好的铜薄膜采用环氧树脂慢干胶粘结在PVDF薄膜表面,最后将制成的实验样品安放在鼓包测量仪上进行实验。在PVDF基底上施加均匀油压直到层状结构界面发生破坏。用这种方法,计算出的剪切强度稳定分布在40.9-53.2 kPa之间。(3)采用Abaqus有限元软件建立了二维条件下的硬质薄膜/柔性基底结构的有限元模型,分析了模型中应变分布和发生破坏时界面处应变变化。计算结果表明,由于硬质薄膜的阻碍作用,使柔软基底的水平拉伸变形区域缩小,并集中于加压区域的边缘。柔性薄膜在剪切面位置发生了压缩变形,正是这种压缩变形和硬质薄膜剪切面处的拉伸变形相互作用,使得当压强升高为1800 kPa时剪切面发生破坏,并产生较大的离面位移。本论文利用数字散斑技术对柔性薄膜材料的力学性能进行了研究。实验结果表明数字散斑技术可以有效地测量PVDF薄膜材料的弹性模量和铜/聚偏氟乙烯(PVDF)基底柔性层状复合薄膜的界面剪切强度。
[Abstract]:Flexible thin film materials are widely used in biomedicine and electronic engineering. However, in practical applications, flexible thin film materials often lack of mechanical properties such as interfacial bonding strength and tensile strength. The failure phenomena such as fracture and peeling of thin films are caused. Because the mechanical properties of flexible thin film materials are directly related to the reliability, stability and life of the components, it is of great significance to study the mechanical properties of flexible thin film materials in order to improve the service performance of flexible thin film materials. Drum cladding method is an experimental method for measuring mechanical parameters such as elastic modulus and interfacial bonding strength of flexible film materials. The advantage of the digital speckle is that it can measure the deformation of the object without contact with the measured object. It has the advantages of high precision and can give the whole field deformation in the field of view and so on. In this paper, the effect of sodium naphthalene treatment on the elastic modulus of PVDF flexible thin film and the interfacial shear strength of rigid film / flexible substrate structure were studied by combining digital speckle method with drum method. The main contents and results are as follows: (1) the effect of sodium naphthalene treatment agent on the mechanical properties of PVDF thin films was studied by digital speckle method. On the drum measuring instrument, the fixed experimental film is installed, and the oil pressure is applied to the sample film by the step motor drive oil cylinder. The deformation process is recorded by the digital speckle technique, and the deformation process is recorded by the digital speckle technique, and the deformation process is recorded by the digital speckle technique. The elastic modulus distribution of PVDF thin films is calculated to be between 2.27 GPa and 2.61 GPa. The experimental results show that sodium naphthalene has no significant effect on the elastic modulus of PVDF films. (2) the interfacial shear strength of copper / polyvinylidene fluoride (PVDF) thin films is studied by digital speckle method. First, the PVDF film is bonded to the steel base with the center hole and completely covered with the central oil hole, then the copper film is bonded to the surface of the PVDF film with epoxy resin slow-drying adhesive, and then the copper film is bonded to the surface of the PVDF film by epoxy resin slow-drying adhesive. Finally, the experimental samples were placed on the drum measuring instrument to carry on the experiment. The uniform oil pressure was applied on the PVDF substrate until the interface of the layered structure was destroyed. Using this method, the stable distribution of shear strength is between 40.9 and 53.2 kPa. (3) the finite element model of rigid film / flexible substrate structure under two-dimensional conditions is established by using Abaqus finite element software. The strain distribution in the model and the strain change at the interface during failure are analyzed. The results show that the horizontal tensile deformation region of the soft substrate is reduced due to the hindrance of the rigid film, and it is concentrated on the edge of the compression region. The compression deformation of the flexible film occurs at the shear plane. It is the interaction between the compression deformation and the tensile deformation at the shear plane of the rigid film, which results in the failure of the shear plane and the large off-plane displacement when the pressure increases to 1800 kPa. In this paper, the mechanical properties of flexible thin film materials were studied by digital speckle technique. The experimental results show that the digital speckle technique can effectively measure the elastic modulus of PVDF thin films and the interfacial shear strength of copper / polyvinylidene fluoride (PVDF) thin films.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2

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