IMECH-IR  > 非线性力学国家重点实验室
薄膜/基底界面撕脱全过程力学行为的定量预测
英文题名Quantitative prediction of the whole interfacial peeling behavior of film/substrate systems
尹涵彬1,2
导师梁立红
2018-05-18
学位授予单位中国科学院大学
学位授予地点北京
学位类别硕士
学位专业固体力学
关键词薄膜/基底系统 起始撕脱 稳态撕脱 界面断裂韧度 界面强度 薄膜弯曲刚度 基底模量 撕脱力
摘要

薄膜/基底系统广泛应用于电子工业、航空航天、医疗器械、仿生器件等多个领域,经典Kendall模型作为描述界面撕脱行为的理论工具,被普遍接受。然而,经典Kendall模型仅描述弹性薄膜/基底系统界面的稳态撕脱阶段,不能描述界面撕脱全过程,亦不能揭示界面断裂韧度与界面强度两个重要参量各自对界面行为影响的物理机制。本文以弹性膜/基系统为研究对象,应用内聚力模型描述界面作用,建立了薄膜/基底界面撕脱全过程理论模型,并开展相应的数值模拟及撕脱实验,综合理论、数值与实验结果,拓展经典的Kendall模型,研究了薄膜、界面以及基底性质对膜/基界面撕脱行为的影响。主要开展了以下三方面工作:

1、基于双线性内聚力界面模型,建立了以L-J势描述界面作用的薄膜/基底撕脱模型中界面势函数参数与界面强度及界面断裂韧度间的解析表达,实现了界面撕脱行为的定量预测。

已有L-J势描述的薄膜/基底界面全过程撕脱模型,由于L-J势函数中的参数难以确定,对真实膜/基界面行为难以实现定量预测。结合双线性内聚力界面模型和L-J势界面模型,本文建立了一种确定L-J势函数参数的方法,势参数直接与界面强度及界面断裂韧度相关,使得理论模型可定量化分析界面撕脱行为的全过程。相应的薄膜/基底界面撕脱实验及有限元数值仿真结果在界面起始撕脱到稳态撕脱的整个过程都能与理论预测很好地吻合,证明了确定L-J势函数参数方法的可靠性。进一步基于有限元方法,讨论了撕脱角度为90度时界面强度及界面断裂韧度对界面撕脱全过程的影响,发现稳态阶段的撕脱力仅依赖于界面断裂韧度,而最大撕脱力受界面断裂韧度、界面强度、及薄膜弯曲刚度共同影响。

2、针对薄膜弯曲刚度较大及界面强度较高的薄膜/基底系统,基于小变形梁模型及内聚力界面描述,给出了界面最大撕脱力解析表达,并发现薄膜初始悬臂长度对最大撕脱力的影响规律。

实验及理论发现,当薄膜弯曲刚度和界面强度相对较高时,最大撕脱力往往出现在稳态撕脱阶段之前,且大于稳态撕脱力。现有描述撕脱全过程的理论模型无法解析预测最大撕脱力。基于常应力内聚力界面模型,假设薄膜变形符合小变形梁假设,分析了界面撕脱行为的全过程,并给出了90度情况下最大撕脱力的解析表达,理论预测与实验结果吻合,进一步解释了最大撕脱力随薄膜初始自由悬臂长度的增加而减小的现象。结合本文给出的最大撕脱力和Kendall模型的稳态撕脱力表达,提出了一种直接测量弹性薄膜/基底系统界面断裂韧度和界面强度的实验方法。

3、结合有限元仿真和撕脱实验,初步研究了基底模量对于撕脱全过程的影响规律。

刚性基底是理想化的,弹性材料是更为一般化的情况。结合有限元仿真分析及基底模量不同的撕脱实验发现:基底模量减小,稳态撕脱力不变,最大撕脱力减小。

 

英文摘要

Film/substrate systems play an important role in various industries, such as bionic device designing, medical protection, modern material manufacturing, etc. Kendall’s model as a classical theory on the interfacial behavior of an elastic film peeling from a rigid substrate has been widely accepted. It only focuses on the steady-state peeling stage, but cannot describe the peeling behavior of the whole peeling process and cannot uncover the effects of the interface strength and the interface toughness (two dominant parameters of interface) on the peeling behavior and the related mechanism. In present thesis, a series of models describing the whole peeling behavior of the elastic film/substrate system are developed by introducing interface cohesive zone models, and the corresponding numerical simulations and peeling tests are also carried out. By combining the results of the theoretical predictions, simulations and experiments, the classical Kendall’s model is extended, and the effects of the film, substrate and interface properties on the interfacial peeling behavior of the film/substrate system and the related mechanism are uncovered. The thesis work mainly includes three parts as follows:

1. By introducing the bilinear cohesive zone model, the parameters of L-J potential, describing the interfacial properties of film/substrate systems, are analytically expressed based on the interface toughness and interface strength. And quantitative prediction of the whole peeling process is realized.  

Although the whole peeling behavior was once well modeled theoretically by introducing Lennard-Jones (L-J) potential to describe the interface interaction, the parameters in the L-J potential are difficult to be determined experimentally and thus the previous model cannot predict quantitatively in real applications. By combining the constitutive relation of the bilinear cohesive zone model with the L-J potential, a method to determine the parameters of L-J potential and a developed model are established here. Both the experimental measurement and the finite element analysis agree well with the theoretical prediction based on the present model. Quantitative agreements among these results further demonstrate the validity of the method. Furthermore, the effects of the interface strength and interface toughness on the whole peeling behavior are analyzed based on the finite element analysis. It is found that when peeling angle is 90 degree, the peeling force at the steady-state stage is only affected by the interface toughness, while the peeling force before the steady-state stage is significantly influenced by the interface toughness, interface strength and the bending stiffness of the film.

 2. For a system with relatively high bending stiffness of the film or with relatively strong interface strength, by introducing the beam theory and the constant-stress cohesive zone model, an analytical expression of the maximum peeling force is derived, and the effect of initial length of the cantilever on the maximum peeling force and the related mechanism are discussed.

For an elastic film/substrate system, the maximum peeling force is always lager than the steady-state peeling force, especially when the bending stiffness of the film is relatively higher or the interface strength is relatively higher. So far, all of the predictions on the maximum peeling force are numerical results, an analytical solution like Kendall’s model is lacking. By introducing the constant-stress interface cohesive zone model describing the interface interaction and the small strain beam theory describing the film’s deformation, a new model on the whole peeling process is built here. According to this peeling model, an analytical expression of the maximum peeling force for peeling angle of 90 degree is achieved. The prediction based on the present model agrees well with the experimental measurement, and the model can explain the phenomenon observed in peeling experiments that the maximum peeling force decreases with increasing initial length of the free cantilever. Moreover, by combining present model and Kendall’s model, a new method measuring the interface toughness and interface strength is proposed based on the 90 degree peeling test.

3. By combining the finite element analysis and the peeling experiment, the effect of the substrate’s modulus on the whole peeling behavior is discussed simply.

Since the rigid substrate is an idealized assumption, the elastic substrate in general case is considered further. The simulation based on the finite element method and the corresponding peeling experiments are performed, respectively, the effect of substrate modulus on the whole peeling behavior is found. The results show that the steady-state peeling force keeps invariant with decreasing modulus of the substrate, but the maximum peeling force decreases. 

语种中文
文献类型学位论文
条目标识符http://dspace.imech.ac.cn/handle/311007/73141
专题非线性力学国家重点实验室
作者单位1.中国科学院力学研究所
2.中国科学院大学工程科学学院
推荐引用方式
GB/T 7714
尹涵彬. 薄膜/基底界面撕脱全过程力学行为的定量预测[D]. 北京. 中国科学院大学,2018.
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