Nonlinear Large Deflection of Thin Film Overhung on Compliant Substrate Using Shaft-Loaded Blister Test

2015 ◽  
Vol 82 (9) ◽  
Author(s):  
Luyi Feng ◽  
Xiwen Li ◽  
Tielin Shi
Keyword(s):  
Thin Film ◽  
Constitutive Relation ◽  
Applied Load ◽  
Large Deflection ◽  
Numerical Solutions ◽  
Spring Model ◽  
Coupled Line ◽  
Blister Test ◽  
Line Spring Model ◽  
Contact Part

This paper presents the nonlinear large deflection of the thin film and the effect of substrate deformation on the thin film deflection through the shaft-loaded blister test. The blister of thin film can be divided into two parts, namely, the annular contact brim and the central noncontact bulge. A two-coupled line spring model is developed to describe the deformation of the contact part, and Föppl–Hencky equations are employed to study the constitutive relation between the applied load and the central deflection. The analytical and numerical solutions for the constitutive relation between the applied load and the deflection of thin film with considering the deformation of substrate are derived.

scholarly journals Closed-Form Solution and Experimental Verification for the Axisymmetric Deformation Problem of Blistering Circular Thin Polymer Films under Uniformly Distributed Gas Pressure

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1130
Author(s):  
Zhi-Xin Yang ◽  
Xiao-Ting He ◽  
Si-Rui Wen
Keyword(s):  
Thin Film ◽  
Analytical Solution ◽  
Polymer Films ◽  
Applied Load ◽  
Axisymmetric Deformation ◽  
Gas Pressure ◽  
Transverse Load ◽  
Thin Polymer Films ◽  
Blister Test ◽  
Thin Polymer

The existing studies indicate that the measurement formulas used in blister test techniques, which are used to measure the mechanical properties of thin-film/substrate systems, are usually given based on an approximation—that is, the applied direction of the uniformly distributed transverse load is always vertical, while the applied direction of the uniformly distributed gas pressure is always perpendicular to the surface of the thin film. This approximation will lead to a large measurement error. In this study, we obtained the analytical solution to the problem of axisymmetric deformation of blistering circular thin polymer films under the action of uniformly distributed gas pressure via the power series method. An example is given to illustrate the error caused by the approximation mentioned above, and the validity of the solution presented here is verified. The result shows that the chance of error caused by the approximation increases with the increase in the applied load, and it far exceeds the allowable error of measurement when the applied load is relatively large. In addition, the related experiments of the blistering circular thin polymer film under uniformly distributed gas pressure are carried out, and the experimental results are compared with the theoretical results. The comparison results show that the analytical solution given in this paper is correct. The solution presented here is of great significance to improve the measurement accuracy of the blister test technique.

scholarly journals Impact of chosen force fields and applied load on thin film lubrication

Friction ◽  
2021 ◽  
Author(s):  
Thi D. Ta ◽  
Hien D. Ta ◽  
Kiet A. Tieu ◽  
Bach H. Tran
Keyword(s):  
Thin Film ◽  
Shear Stress ◽  
Surface Structure ◽  
Rheological Properties ◽  
Surface Potential ◽  
Applied Load ◽  
Velocity Slip ◽  
Thin Film Lubrication ◽  
Lubrication Performance ◽  
Film Lubrication

AbstractThe rapid development of molecular dynamics (MD) simulations, as well as classical and reactive atomic potentials, has enabled tribologists to gain new insights into lubrication performance at the fundamental level. However, the impact of adopted potentials on the rheological properties and tribological performance of hydrocarbons has not been researched adequately. This extensive study analyzed the effects of surface structure, applied load, and force field (FF) on the thin film lubrication of hexadecane. The lubricant film became more solid-like as the applied load increased. In particular, with increasing applied load, there was an increase in the velocity slip, shear viscosity, and friction. The degree of ordering structure also changed with the applied load but rather insignificantly. It was also significantly dependent on the surface structure. The chosen FFs significantly influenced the lubrication performance, rheological properties, and molecular structure. The adaptive intermolecular reactive empirical bond order (AIREBO) potential resulted in more significant liquid-like behaviors, and the smallest velocity slip, degree of ordering structure, and shear stress were compared using the optimized potential for liquid simulations of united atoms (OPLS-UAs), condensed-phase optimized molecular potential for atomic simulation studies (COMPASS), and ReaxFF. Generally, classical potentials, such as OPLS-UA and COMPASS, exhibit more solid-like behavior than reactive potentials do. Furthermore, owing to the solid-like behavior, the lubricant temperatures obtained from OPLS-UA and COMPASS were much lower than those obtained from AIREBO and ReaxFF. The increase in shear stress, as well as the decrease in velocity slip with an increase in the surface potential parameter ζ, remained conserved for all chosen FFs, thus indicating that the proposed surface potential parameter ζ for the COMPASS FF can be verified for a wide range of atomic models.

Parametric Deflection Approximations for End-Loaded, Large-Deflection Beams in Compliant Mechanisms

1995 ◽  
Vol 117 (1) ◽  
pp. 156-165 ◽  
Author(s):  
L. L. Howell ◽  
A. Midha
Keyword(s):  
Closed Form ◽  
Large Deflection ◽  
Numerical Solutions ◽  
Compliant Mechanisms ◽  
Elliptic Integral ◽  
Cantilever Beams ◽  
Simple Method ◽  
Body Angle ◽  
Analysis And Design ◽  
Integral Solutions

Geometric nonlinearities often complicate the analysis of systems containing large-deflection members. The time and resources required to develop closed-form or numerical solutions have inspired the development of a simple method of approximating the deflection path of end-loaded, large-deflection cantilever beams. The path coordinates are parameterized in a single parameter called the pseudo-rigid-body angle. The approximations are accurate to within 0.5 percent of the closed-form elliptic integral solutions. A physical model is associated with the method, and may be used to simplify complex problems. The method proves to be particularly useful in the analysis and design of compliant mechanisms.

scholarly journals Constitutive Relation for Large Deformations of Fiber-Reinforced Rubberlike Materials with Different Response in Tension and Compression

2016 ◽  
Vol 44 (1) ◽  
pp. 51-72 ◽  
Author(s):  
Qian Li ◽  
David A. Dillard ◽  
Romesh C. Batra
Keyword(s):  
Constitutive Relation ◽  
Large Deformations ◽  
Numerical Solutions ◽  
Boundary Value ◽  
Strain Tensor ◽  
Fiber Direction ◽  
Fiber Reinforced ◽  
Tension And Compression ◽  
Different Response ◽  
Rubberlike Materials

ABSTRACT Fiber-reinforced rubberlike materials commonly used in tires undergo large deformations and exhibit different responses in tension and compression along the fiber direction. Assuming that the response of a fiber-reinforced rubberlike material can be modeled as transversely isotropic with the fiber direction as the axis of transverse isotropy, we express the stored energy function in terms of the five invariants of the right Cauchy-Green strain tensor and account for different response in tension and compression along the fiber direction. The constitutive relation accounts for both material and geometric nonlinearities and incorporates effects of the fifth strain invariant, I5. It has been shown by Merodio and Ogden that in shear dominated deformations, I5 makes a significant contribution to the stress-strain curve. We have implemented the proposed constitutive relation in the commercial software, LS-DYNA. The numerical solutions of a few boundary value problems studied here agree with their analytical solutions derived by using Ericksen's inverse approach, in which part of the solution is assumed and unknowns in the presumed solution are found by analyzing the pertinent boundary value problem. However, computed results have not been compared with experimental findings. When test data become available, one can modify the form of the strain energy density and replace the proposed constitutive relation by the new one in LS-DYNA.

Thin Film Adhesion Study in Microelectronic Packaging

1991 ◽  
Vol 239 ◽  
Author(s):  
H. S. Jeong ◽  
Y. Z. Chu ◽  
M. B. Freiler ◽  
C. Durning ◽  
R. C. White
Keyword(s):  
Thin Film ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Microelectronic Packaging ◽  
Elastic Model ◽  
Blister Test ◽  
Linear Elastic ◽  
Film Adhesion ◽  
Thin Film Adhesion ◽  
Cure Temperature

ABSTRACTFracture energy (Ga) of BPDA-PDA polyimide (PI) on modified and unmodified Si surfaces was measured by the “blister” test as a function of final cure temperature. It is proven quantitatively that surface modification prior to thin film deposition enhances adhesion. Metal adhesion to PI was also measured by the same method. Reproducibility of the data was found to be exceptionally good for both cases. The linear elastic model is quite valid for the test of thin film adhesion. Therefore, it is believed that this test is best suited for Ga measurements in the study of thin film adhesion for microelectronic packaging.

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