Mechanics of Periodic Film Cracking in Bilayer Structures Under Stretching

2018 ◽  
Vol 85 (7) ◽  
Author(s):  
Xianhong Meng ◽  
Zihao Wang ◽  
Sandra Vinnikova ◽  
Shuodao Wang
Keyword(s):  
Flexible Electronics ◽  
Biological Tissues ◽  
Common Phenomenon ◽  
Soft Substrate ◽  
Element Analysis ◽  
Normal Stress Distribution ◽  
Material Parameters ◽  
Film Cracking ◽  
Analytical Result ◽  
Periodic Crack

In a bilayer structure consisting of a stiff film bonded to a soft substrate, the stress in the film is much larger when the rigidity of the film is much higher than that of the substrate so that film cracking is a common phenomenon in bilayer structures such as flexible electronics and biological tissues. In this paper, a theoretical model is developed to analyze the normal stress distribution in the structure to explain the mechanism of the formation of periodic crack patterns. The effects of geometrical and material parameters are systematically discussed. The analytical result agrees well with finite element analysis, and the prediction of spacing between cracks agrees with experiments from the literature.

Lifetime Prediction of Tires with Regard to Oxidative Aging5

2008 ◽  
Vol 36 (1) ◽  
pp. 63-79 ◽  
Author(s):  
L. Nasdala ◽  
Y. Wei ◽  
H. Rothert ◽  
M. Kaliske
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Superposition Principle ◽  
Accelerated Aging ◽  
Material Model ◽  
Aging Behavior ◽  
Element Analysis ◽  
Material Parameters ◽  
Reaction Processes

Abstract It is a challenging task in the design of automobile tires to predict lifetime and performance on the basis of numerical simulations. Several factors have to be taken into account to correctly estimate the aging behavior. This paper focuses on oxygen reaction processes which, apart from mechanical and thermal aspects, effect the tire durability. The material parameters needed to describe the temperature-dependent oxygen diffusion and reaction processes are derived by means of the time–temperature–superposition principle from modulus profiling tests. These experiments are designed to examine the diffusion-limited oxidation (DLO) effect which occurs when accelerated aging tests are performed. For the cord-reinforced rubber composites, homogenization techniques are adopted to obtain effective material parameters (diffusivities and reaction constants). The selection and arrangement of rubber components influence the temperature distribution and the oxygen penetration depth which impact tire durability. The goal of this paper is to establish a finite element analysis based criterion to predict lifetime with respect to oxidative aging. The finite element analysis is carried out in three stages. First the heat generation rate distribution is calculated using a viscoelastic material model. Then the temperature distribution can be determined. In the third step we evaluate the oxygen distribution or rather the oxygen consumption rate, which is a measure for the tire lifetime. Thus, the aging behavior of different kinds of tires can be compared. Numerical examples show how diffusivities, reaction coefficients, and temperature influence the durability of different tire parts. It is found that due to the DLO effect, some interior parts may age slower even if the temperature is increased.

scholarly journals Simulasi Pembebanan Komponen Bender pada Desain Mesin Begel Fabricator Menggunakan Software Autodesk Inventor 2020

2021 ◽  
Vol 2 (2) ◽  
pp. 93-97
Author(s):  
Satriawan Dini Hariyanto ◽  
Wikan Kurniawan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cast Iron ◽  
Mild Steel ◽  
Modulus Of Elasticity ◽  
Material Parameter ◽  
Element Analysis ◽  
Material Parameters ◽  
Constituent Material ◽  
Loading Parameter

Stress analysis of the bender components in the design of the begel fabricator machine was carried out using FEA (Finite Element Analysis) with three variations of the constituent material parameters, namely 6061 aluminum, mild steel, and cast iron with a modulus of elasticity of 68.9 GPa, 220 GPa, 120.5 GPa, respectively. The test is carried out by a loading parameter 2520 MPa and fixed constraint. The maximum von misses stress and displacement obtained for each material parameter components using aluminum, mild steel, and cast iron are 17.78 MPa; 0.00765, 17.49 MPa; 0.00229, 17.62 MPa; 0.00427 respectively.

Direct Comparison of Some Recent Rubber Elasticity Models

2000 ◽  
Vol 73 (2) ◽  
pp. 366-384 ◽  
Author(s):  
D. J. Seibert ◽  
N. Schöche
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Element Analysis ◽  
Material Parameters ◽  
Complex Membrane ◽  
The Finite Element Analysis ◽  
Generic Class ◽  
Cubic Model ◽  
Polynomial Models ◽  
Special Case

Abstract The paper compares the Arruda—Boyce model, the van der Waals model and the Reduced Polynomial model—a generic class of polynomial models of which Yeoh's cubic model is a special case—in their ability to predict multiaxial deformation states on the basis of uniaxial measurements. These models are reviewed in the light of novel experimental data, giving ample space to the derivation of the equations needed for optimization of the material parameters. The technological relevance of these findings is exemplified in the finite element analysis (FEA) of a complex membrane.

Numerical Analysis on the Wrinkling Instability of a Stiff Film Adhering to an Elastic Substrate with a Graded Coating

2019 ◽  
Vol 11 (02) ◽  
pp. 1950015 ◽  
Author(s):  
Feng Gao ◽  
Wang Guo ◽  
Peijian Chen ◽  
Chengzheng Cai ◽  
Guangjian Peng
Keyword(s):  
Flexible Electronics ◽  
Critical Strain ◽  
Present Finding ◽  
Elastic Substrate ◽  
Material Parameters ◽  
Numerical Result ◽  
Graded Coating ◽  
Inhomogeneous Coating ◽  
Graded Properties ◽  
Film Substrate

The wrinkling instability of a stiff film adhering to a pre-strained inhomogeneous bi-layer substrate consisting of a homogeneous substrate and a graded coating is investigated in the present paper. The critical strain, wavelength and amplitude of the film/inhomogeneous substrate system are calculated numerically and analyzed comprehensively. Compared with the numerical result, a theoretical model is introduced to approximately predict the wrinkling responses of the system. The influence of various geometric and material parameters on the wrinkling behavior is mainly focused. The wrinkling responses are found to be highly related to the graded laws and the thickness of the inhomogeneous coating as well as the Poisson’s ratio. What is more, a proper choice of graded properties of a substrate can improve the wrinkling response of a film/substrate system. The present finding should be very meaningful to guide the design of various stretchable and flexible electronics.

Numerical Implementation and Finite Element Analysis of Anisotropic Hyperelastic Biomaterials - Influence of Fibers Orientation

2013 ◽  
Vol 554-557 ◽  
pp. 2414-2423 ◽  
Author(s):  
Rachid Djeridi ◽  
Mohand Ould Ouali
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fiber Orientation ◽  
Mechanical Response ◽  
Theoretical Study ◽  
Constitutive Law ◽  
Anisotropic Behavior ◽  
Element Analysis ◽  
Material Parameters ◽  
Fibers Orientation

Modeling anisotropic behavior of fiber reinforced rubberlike materials is actually of a great interest in many industrials sectors. Indeed, accurately description of the mechanical response and damage of such materials allows the increase of the lifecycle of these materials which generally evolve under several environment conditions. In this paper theoretical study and finite element analysis of anisotropic biomaterials is presented. The mechanical model adopted to achieve this study has been implemented into the finite element code Abaqus using an implicit scheme. This constitutive law has been utilized to perform some numerical simulations. The material parameters of the model have been determined by numerical calibration. One fiber family is considered in this work. Effects of the fiber orientation on the mechanical response and stiffness change of biomaterial is studied. Both the compressible and incompressible states have been taken into account. The results show firstly the capability of the model to reproduce the known results and that optimal fiber orientation can be found.

Thin Film Fracture During Nanoindentation of Hard Film – Soft Substrate Systems

2001 ◽  
Vol 695 ◽  
Author(s):  
M. Pang ◽  
K.D. Weaver ◽  
D.F. Bahr
Keyword(s):  
Mechanical Response ◽  
Film Formation ◽  
Permanent Deformation ◽  
Dislocation Nucleation ◽  
Titanium Oxides ◽  
Soft Substrate ◽  
Aluminum Oxides ◽  
Anodic Titanium Oxide ◽  
Formation Conditions ◽  
Film Cracking

ABSTRACTNanoindentation testing of hard film – soft substrate systems can exhibit permanent deformation prior to a yield excursion, indicating that the occurrence of this sudden discontinuity is predominantly controlled by the hard film cracking rather than dislocation nucleation and multiplication. In a previous paper, a model was developed to predict the mechanical response prior to hard film fracture. In the current study a this model, which superimposes large deflection of the hard film and plastic deformation of the substrate the model, is further refined by testing a variety of materials with different film formation conditions. The tested materials include anodic titanium oxide on titanium, thermal aluminum oxide on aluminum and sputtered tungsten films on aluminum. The film fracture strength of titanium oxides on titanium is estimated as 15 GPa and that of aluminum oxides on aluminum is around 10 GPa. In the case of vacuum sputtered tungsten film on aluminum, the tungsten layer is likely plastically deformed. The strain at film fracture is roughly estimated to be 3.4%.

scholarly journals A widely adaptable analytical method for thermal analysis of flexible electronics with complex heat source structures

2019 ◽  
Vol 475 (2228) ◽  
pp. 20190402 ◽  
Author(s):  
Yafei Yin ◽  
Min Li ◽  
Wei Yuan ◽  
Xiaolian Chen ◽  
Yuhang Li
Keyword(s):  
Heat Source ◽  
Thermal Management ◽  
Flexible Electronics ◽  
Analytical Method ◽  
Thermal Field ◽  
Complex Shape ◽  
Source Region ◽  
Electronic Devices ◽  
Crucial Issue ◽  
Element Analysis

Flexible electronics, as a relatively new category of device, exhibit prodigious potential in many applications, especially in bio-integrated fields. It is critical to understand that thermal management of certain kinds of exothermic flexible electronics is a crucial issue, whether to avoid or to take advantage of the excessive temperature. A widely adaptable analytical method, validated by finite-element analysis and experiments, is conducted to investigate the thermal properties of exothermic flexible electronics with a heat source in complex shape or complex array layout. The main theoretical strategy to obtain the thermal field is through an integral along the complex curve source region. The results predicted by the analytical model enable accurate control of temperature and heat flow in the flexible electronics, which may help in the design and fabrication of flexible electronic devices in the future.

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