scholarly journals Investigation of Adhesive’s Material in Hermetic MEMS Package for Interfacial Crack between the Silver Epoxy and the Metal Lid during the Precondition Test

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5626
Author(s):  
Mei-Ling Wu ◽  
Jia-Shen Lan
Keyword(s):  
Internal Pressure ◽  
Cohesive Zone Model ◽  
Experimental Testing ◽  
Low Cost ◽  
Interfacial Crack ◽  
Bonding Layer ◽  
Zone Model ◽  
Micro Electro Mechanical Systems ◽  
Epoxy Material ◽  
Silver Epoxy

A hermetic Micro-Electro-Mechanical Systems (MEMS) package with a metal lid is investigated to prevent lid-off failure and improve its reliability during the precondition test. While the MEMS package benefits from miniaturization and low cost, a hermetic version is highly sensitive to internal pressure caused by moisture penetration and the reflow process, thus affecting its reliability. In this research, the finite element method is applied to analyze the contact stress between the metal lid and the silver epoxy by applying the cohesive zone model (CZM). Moreover, the red dye penetration test is applied, revealing a microcrack at the metal lid/silver epoxy interface. Further analyses indicate that the crack is caused by internal pressure. According to the experimental testing and simulation results, the silver epoxy material, the curing process, the metal lid geometry, and the bonding layer contact area can enhance the bonding strength between the metal lid and the substrate.

scholarly journals A Numerical and Experimental Study of Adhesively-Bonded Polyethylene Pipelines

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1531 ◽  
Author(s):  
Guilpin ◽  
Franciere ◽  
Barton ◽  
Blacklock ◽  
Birkett
Keyword(s):  
Cohesive Zone ◽  
Adhesive Bonding ◽  
Structural Integrity ◽  
Cohesive Zone Model ◽  
Low Cost ◽  
Element Model ◽  
Zone Model ◽  
Adhesively Bonded ◽  
Lap Shear ◽  
Lap Shear Test

Adhesive bonding of polyethylene gas pipelines is receiving increasing attention as a replacement for traditional electrofusion welding due to its potential to produce rapid and low-cost joints with structural integrity and pressure tight sealing. In this paper a mode-dependent cohesive zone model for the simulation of adhesively bonded medium density polyethylene (MDPE) pipeline joints is directly determined by following three consecutive steps. Firstly, the bulk stress–strain response of the MDPE adherend was obtained via tensile testing to provide a multi-linear numerical approximation to simulate the plastic deformation of the material. Secondly, the mechanical responses of double cantilever beam and end-notched flexure test specimens were utilised for the direct extraction of the energy release rate and cohesive strength of the adhesive in failure mode I and II. Finally, these material properties were used as inputs to develop a finite element model using a cohesive zone model with triangular shape traction separation law. The developed model was successfully validated against experimental tensile lap-shear test results and was able to accurately predict the strength of adhesively-bonded MPDE pipeline joints with a maximum variation of <3%.

scholarly journals Evaluations of Fracture Injection Pressure and Fracture Mouth Width during Separate-Layer Fracturing with Temporary Plugging

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Bo Wang ◽  
Fujian Zhou ◽  
Tianbo Liang ◽  
Daobing Wang ◽  
Liyang Gao ◽  
...  
Keyword(s):  
Tensile Strength ◽  
High Efficiency ◽  
Cohesive Zone Model ◽  
Low Cost ◽  
Injection Pressure ◽  
Injection Rate ◽  
Zone Model ◽  
Multiple Layer ◽  
Separate Layer ◽  
Mouth Width

Separate-layer fracturing with temporary plugging (SLFTP) is a potential way to stimulate multiple layer reservoirs due to its low cost, low risk, and high efficiency. In this study, based on the cohesive zone model (CZM), a 3D fully fluid-solid coupling and multiple layer model is established to investigate factors influencing fracture injection pressure and fracture mouth width. The cohesive layer properties are based on the reported study, which have been validated through a series of numerical experiments. Innovatively, the spring model is innovatively proposed to represent the plugging effect of diverting agents and prop the aperture of the previous fractures. Simulation results reveal that the effects of previous fractures in multiple layer formations can be neglected, which is quite different from multistage fracturing for horizontal wells. Fracture injection pressure can be evaluated more accurately by taking the following factors into consideration: the minimum horizontal principal stress, rock tensile strength, injection rate, and pore pressure enhancement. Further, fracture mouth width is strongly influenced by rock tensile strength, Young’s modulus, and injection rate. This study provides a guidance for candidate well selection and diverting agent optimization during SLFTP in multilayer formations.

Finite Element Analysis of the Effects of Thermally Grown Oxide Thickness and Interface Asperity on the Cracking Behavior Between the Thermally Grown Oxide and the Bond Coat

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Jishen Jiang ◽  
Bingqian Xu ◽  
Weizhe Wang ◽  
Richard Amankwa Adjei ◽  
Xiaofeng Zhao ◽  
...  
Keyword(s):  
Finite Element ◽  
Bond Coat ◽  
Cohesive Zone Model ◽  
Interfacial Crack ◽  
Maximum Tensile Stress ◽  
Thermally Grown Oxide ◽  
Zone Model ◽  
Element Analysis ◽  
Cracking Behavior ◽  
Thermally Grown

Finite element simulations based on an interface cohesive zone model (CZM) have been developed to mimic the interfacial cracking behavior between the α−Al2O3 thermally grown oxide (TGO) and the aluminum-rich Pt–Al metallic bond coat (BC) during cooling from high temperature to ambient temperature. A two-dimensional half-periodic sinusoidal geometry corresponding to interface undulation is modeled. The effects of TGO thickness and interface asperity on the stress distribution and the cracking behavior are examined by parametric studies. The simulation results show that cracking behavior due to residual stress and interface asperity during cooling process leads to stress redistribution around the rough interface. The TGO thickness has strong influence on the maximum tensile stress of TGO and the interfacial crack development. For the sinusoidal asperities, there exists a critical amplitude above which the interfacial cracking is energetically favored. For any specific TGO thickness, crack initiation is dominated by the amplitude while crack propagation is restricted to the combine actions of the wavelength and the amplitude of the sinusoidal asperity.

FE Analysis of the Effects of TGO Thickness and Interface Asperity on the Cracking Behavior Between the TGO and the Bond Coat

2016 ◽  
Author(s):  
Jishen Jiang ◽  
Bingqian Xu ◽  
Weizhe Wang ◽  
Richard Amankwa Adjei ◽  
Xiaofeng Zhao ◽  
...  
Keyword(s):  
Bond Coat ◽  
Cohesive Zone Model ◽  
Interfacial Crack ◽  
Maximum Tensile Stress ◽  
Thermally Grown Oxide ◽  
Zone Model ◽  
Cracking Behavior ◽  
Metallic Bond ◽  
Parametric Studies ◽  
Α Al2o3

Finite element simulations based on an interface cohesive zone model (CZM) have been developed to mimic the interfacial cracking behavior between the α-Al2O3 thermally grown oxide (TGO) and the aluminum rich Pt–Al metallic bond coat (BC) during cooling from high temperature to ambient temperature. A two dimensional half-periodic sinusoidal geometry corresponding to interface undulation is modelled. The effects of TGO thickness and interface asperity on the stress distribution and the cracking behavior are examined by parametric studies. The simulation results show that cracking behavior due to residual stress and interface asperity during cooling process leads to stress redistribution around the rough interface. The TGO thickness has strong influence on the maximum tensile stress of TGO and the interfacial crack development. For the sinusoidal asperities, there exist a critical amplitude above which interfacial cracking is energetically favored. For any specific TGO thickness, crack initiation is dominated by the amplitude while crack propagation is restricted to the combine actions of the wavelength and the amplitude of the sinusoidal asperity.

Numerical Study on the Delamination Onset in Drilling Composite Materials

2012 ◽  
Vol 472-475 ◽  
pp. 2256-2259 ◽  
Author(s):  
Shi Yong Sun ◽  
Zi Bin Yan ◽  
Rui Yang
Keyword(s):  
Finite Element ◽  
Composite Materials ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Numerical Study ◽  
Interfacial Crack ◽  
Element Model ◽  
Zone Model ◽  
Drilling Force ◽  
Interface Elements

The theoretical analysis and numerical study focused on the delamination onset of composites in drilling are presented. An analytical model considering the form of loads distribution is built. The formulas based on the fracture mechanics theory are given for predicting the critical drilling force of delamination onset. A finite element model is used to simulate the process of interfacial crack growth between layers. The interface elements are employed to account for delamination based on cohesive zone model. Some numerical results are given for verifying the validity of the distribution loading model and discussing the delamination onset and growth in drilling composites.

scholarly journals Ultrasonic Deicing Efficiency Prediction and Validation for a Flat Deicing System

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.

Sign in / Sign up

Export Citation Format

Share Document