Study on the interfacial adhesion property of low-k thin film by the surface acoustic waves with cohesive zone model

Intermetallic alloys of Ni-Al have important applications in high temperature anti-corrosive coatings, engine and turbine related materials, and shape memory devices. Predicting failure behavior of these materials is difficult using purely continuum model, since several of the material constants are complicated functions of micro and nano-scale details. This includes solid-solid phase transformation. In the present paper, a framework for analyzing fracture in two-dimensional planar domain is developed using a molecular dynamic (MD) simulation and extended finite element method (XFEM). The framework is then applied to simulate fracture in Ni-Al thin-film. Effect of Ni Al crystallites of various sizes on the mechanical properties is analyzed using direct MD simulations. Initiation and growth of crack under slow (quasi-static) tensile loading in mode-I condition is considered. Mechanical properties at room temperature are estimated via MD simulations, which are further used in the XFEM at the continuum scale. A cohesive zone model for the macroscopic XFEM model is implemented, which directly bridges the molecular length-scale via MD framework. Numerical convergence studies are reported for mode-I crack in initially single crystal B2 Ni-Al thin film.

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Prediction of delamination strength at interface between thin film and substrate by cohesive zone model

Vietnam Journal of Mechanics ◽

10.15625/0866-7136/28/4/5585 ◽

2006 ◽

Vol 28 (4) ◽

pp. 252-262 ◽

Cited By ~ 1

Author(s):

Do Van Truong ◽

Hiroyuku Hirakata ◽

Takayuki Katamura

Keyword(s):

Thin Film ◽

Cohesive Zone ◽

Cohesive Zone Model ◽

Electronic Device ◽

Stress Singularity ◽

Zone Model ◽

Cohesive Law ◽

Gold Thin Film ◽

Different Shapes ◽

Interface Edge

An electronic device consists of multi-layered submicron-thick films, and delamination often takes place at an interface edge because of the stress singularity near the edge. Since the stress singularity at an interface edge depends on the edge shape, the fracture mechanics concept cannot be used to compare the delamination strength between the components with different shapes. This paper aims to predict the delamination strength at the interface edge with arbitrary shape using a cohesive zone model. Two different experiments are conducted for a gold thin film on a silicon substrate to calibrate the cohesive law. The validity of the approach is then discussed.

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Ultrasonic Deicing Efficiency Prediction and Validation for a Flat Deicing System

Applied Sciences ◽

10.3390/app10196640 ◽

2020 ◽

Vol 10 (19) ◽

pp. 6640

Author(s):

Zhonghua Shi ◽

Zhenhang Kang ◽

Qiang Xie ◽

Yuan Tian ◽

Yueqing Zhao ◽

...

Keyword(s):

Lead Zirconate Titanate ◽

Cohesive Zone ◽

Cohesive Zone Model ◽

Lead Zirconate ◽

Efficiency Factor ◽

Zone Model ◽

Shear Stresses ◽

Stress Distributions ◽

Total Energy Density ◽

Average Shear

An effective deicing system is needed to be designed to conveniently remove ice from the surfaces of structures. In this paper, an ultrasonic deicing system for different configurations was estimated and verified based on finite element simulations. The research focused on deicing efficiency factor (DEF) discussions, prediction, and validations. Firstly, seven different configurations of Lead zirconate titanate (PZT) disk actuators with the same volume but different radius and thickness were adopted to conduct harmonic analysis. The effects of PZT shape on shear stresses and optimal frequencies were obtained. Simultaneously, the average shear stresses at the ice/substrate interface and total energy density needed for deicing were calculated. Then, a coefficient named deicing efficiency factor (DEF) was proposed to estimate deicing efficiency. Based on these results, the optimized configuration and deicing frequency are given. Furthermore, four different icing cases for the optimize configuration were studied to further verify the rationality of DEF. The effects of shear stress distributions on deicing efficiency were also analyzed. At same time, a cohesive zone model (CZM) was introduced to describe interface behavior of the plate and ice layer. Standard-explicit co-simulation was utilized to model the wave propagation and ice layer delamination process. Finally, the deicing experiments were carried out to validate the feasibility and correctness of the deicing system.

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Simulation of ductile fracture of zirconium alloys based on triaxiality dependent cohesive zone model

Acta Mechanica ◽

10.1007/s00707-021-03032-2 ◽

2021 ◽

Author(s):

C. Fang ◽

X. Guo ◽

G. J. Weng ◽

J. H. Li ◽

G. Chen

Keyword(s):

Ductile Fracture ◽

Cohesive Zone ◽

Cohesive Zone Model ◽

Zirconium Alloys ◽

Zone Model

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An Improved Cohesive Zone Model for Interface Mixed-Mode Fractures of Railway Slab Tracks

Applied Sciences ◽

10.3390/app11010456 ◽

2021 ◽

Vol 11 (1) ◽

pp. 456

Author(s):

Yanglong Zhong ◽

Liang Gao ◽

Xiaopei Cai ◽

Bolun An ◽

Zhihan Zhang ◽

...

Keyword(s):

Interface Crack ◽

Cohesive Zone ◽

Mixed Mode ◽

Cohesive Zone Model ◽

Complex Loading ◽

Bending Test ◽

Mixed Mode Fracture ◽

Zone Model ◽

Slab Track ◽

Interfacial Cracks

The interface crack of a slab track is a fracture of mixed-mode that experiences a complex loading–unloading–reloading process. A reasonable simulation of the interaction between the layers of slab tracks is the key to studying the interface crack. However, the existing models of interface disease of slab track have problems, such as the stress oscillation of the crack tip and self-repairing, which do not simulate the mixed mode of interface cracks accurately. Aiming at these shortcomings, we propose an improved cohesive zone model combined with an unloading/reloading relationship based on the original Park–Paulino–Roesler (PPR) model in this paper. It is shown that the improved model guaranteed the consistency of the cohesive constitutive model and described the mixed-mode fracture better. This conclusion is based on the assessment of work-of-separation and the simulation of the mixed-mode bending test. Through the test of loading, unloading, and reloading, we observed that the improved unloading/reloading relationship effectively eliminated the issue of self-repairing and preserved all essential features. The proposed model provides a tool for the study of interface cracking mechanism of ballastless tracks and theoretical guidance for the monitoring, maintenance, and repair of layer defects, such as interfacial cracks and slab arches.

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Formation of a Complex Topologies of SAW-Based Inertial Sensors by Laser Thin Film Local Evaporation

Micromachines ◽

10.3390/mi12010010 ◽

2020 ◽

Vol 12 (1) ◽

pp. 10

Author(s):

Alexander Kukaev ◽

Dmitry Lukyanov ◽

Denis Mikhailenko ◽

Daniil Safronov ◽

Sergey Shevchenko ◽

...

Keyword(s):

Thin Film ◽

Acoustic Wave ◽

Surface Acoustic Wave ◽

Acoustic Waves ◽

Inertial Sensors ◽

Surface Acoustic Waves ◽

Sensing Element ◽

Small Series ◽

Evaporation Technique ◽

Photolithography Process

Originally, sensors based on surface acoustic waves are fabricated using photolithography, which becomes extremely expensive when a small series or even single elements are needed for the research. A laser thin film local evaporation technique is proposed to substitute the photolithography process in the production of surface acoustic wave based inertial sensors prototypes. To estimate its potential a prototype of a surface acoustic wave gyroscope sensing element was fabricated and tested. Its was shown that the frequency mismatch is no more than 1%, but dispersion of the wave on small inertial masses leads to a spurious parasitic signal on receiving electrodes. Possible ways of its neglecting is discussed.

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