A Theory for Multi Damage Evaluation of TiN Thin Film

2000 ◽  
Vol 653 ◽  
Author(s):  
Kazunori Misawa ◽  
Tomonaga Okabe ◽  
Masaaki Yanaka ◽  
Masao Shimizu ◽  
Nobuo Takeda
Keyword(s):  
Thin Film ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Titanium Alloy ◽  
Tensile Load ◽  
Damage Evaluation ◽  
Shear Lag ◽  
New Approach ◽  
Shear Lag Model ◽  
Lag Model

AbstractThe present paper experimentally studies the cracking phenomena of a TiN thin film on a titanium alloy, and presents a new approach to predict the number of cracks under tensile load. An elastoplastic shear-lag model is developed to obtain the stress distribution caused by the film cracks, which is found to agree well with that calculated with FEM. The number of thin film cracks is predicted using a Monte Carlo simulation using the present approach, and favourably compared with the experimental results.

scholarly journals Constraint Effects on Thin Film Channel Cracking Behavior

2005 ◽  
Vol 20 (9) ◽  
pp. 2266-2273 ◽  
Author(s):  
Ting Y. Tsui ◽  
Andrew J. McKerrow ◽  
Joost J. Vlassak
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Silicon Substrate ◽  
Shear Lag ◽  
Shear Lag Model ◽  
Lag Model ◽  
Buffer Layer Thickness ◽  
Cds Film

One of the most common forms of cohesive failure observed in brittle thin film subjected to a tensile residual stress is channel cracking, a fracture mode in which through-film cracks propagate in the film. The crack growth rate depends on intrinsic film properties, residual stress, the presence of reactive species in the environments, and the precise film stack. In this paper, we investigate the effect of various buffer layers sandwiched between a brittle carbon-doped-silicate (CDS) film and a silicon substrate on channel cracking of the CDS film. The results show that channel cracking is enhanced if the buffer layer is more compliant than the silicon substrate. Crack velocity increases with increasing buffer layer thickness and decreasing buffer layer stiffness. This is caused by a reduction of the constraint imposed by the substrate on the film and a commensurate increase in energy release rate. The degree of constraint is characterized experimentally as a function of buffer layer thickness and stiffness, and compared to the results of a simple shear lag model that was proposed previously. The results show that the shear lag model does not accurately predict the effect of the buffer layer.

scholarly journals Application of the Equivalent Constraint Model to Investigate Stiffness Properties of Transversally Cracked and Split Frp Laminates

1999 ◽  
Vol 8 (5) ◽  
pp. 096369359900800 ◽  
Author(s):  
M. Kashtalyan ◽  
C. Soutis
Keyword(s):  
Matrix Cracking ◽  
Shear Lag ◽  
Transverse Cracks ◽  
New Approach ◽  
Shear Lag Model ◽  
Transverse Cracking ◽  
Stiffness Properties ◽  
Lag Model ◽  
Equivalent Constraint Model ◽  
Constraint Model

A new approach based on the Equivalent Constraint Model (ECM) [ 1 ] of the damaged lamina is applied to investigate the stiffness degradation in [0m/90n]s laminates due to matrix cracking both in the 90° (transverse cracking) and 0° (splitting) plies. The advantage of the approach is that it avoids cumbersome consideration of a repeated laminate element defined by the intersecting pairs of transverse cracks and splits, intrinsic to the earlier developed models [ 2 – 6 ]. Instead, two coupled problems for ECM laminates are solved. The stress field in the damaged lamina is determined by means of an improved 2-D shear lag analysis, and the reduced stiffness properties are described with the help of Insitu Damage Effective Functions, for which closed form expressions are obtained. Comparison of the new ECM/2-D shear lag model with the earlier developed models shows a reasonable agreement.

Analysis of Stresses for Cross-Ply Laminates with a Matrix Crack under Bending

2011 ◽  
Vol 284-286 ◽  
pp. 492-495
Author(s):  
Qing Dun Zeng ◽  
Mao Hua Ouyang
Keyword(s):  
Failure Mechanism ◽  
Transverse Crack ◽  
Approximate Solutions ◽  
Matrix Crack ◽  
Stress Distributions ◽  
Shear Lag ◽  
New Approach ◽  
Shear Lag Model ◽  
Lag Model ◽  
Shear Lag Theory

On the basis of the shear-lag theory, an analysis was presented for stress redistributions of cross-ply laminates with a transverse matrix crack in the 90º ply under bending by establishing a layered shear-lag model. The present results show that approximate solutions of displacement and stress distributions for cross-ply laminates with a transverse crack under bending can be obtained by using a shear-lag method. The present paper therefore affords a new approach for studying the stress redistributions and failure mechanism for cross-ply laminates with flaw under bending.

Evidence for Interfibrillar Shear Load Transfer Between Sliding Fibrils in Tendon

2013 ◽  
Author(s):  
Spencer E. Szczesny ◽  
Dawn M. Elliott
Keyword(s):  
Load Transfer ◽  
Tensile Load ◽  
Tissue Level ◽  
Collagen Fibrils ◽  
Shear Stresses ◽  
Shear Lag ◽  
Shear Lag Model ◽  
Lag Model ◽  
Tail Tendon ◽  
The Impact

While collagen fibrils are understood to be the primary tensile load bearing components in tendon, how loads applied at the tissue level are transmitted across each element within the tissue hierarchical structure is unclear. A central unresolved question is whether collagen fibrils bear load independently or if the applied load is transferred across the fibrils through interfibrillar shear forces. Relative sliding between fibrils is suggested by findings that fibril strains within rat tail tendon fascicles do not agree with the applied tissue tensile strains [1]. Other studies using confocal microscopy have directly measured sliding behavior [2,3]; however, the impact that interfibrillar sliding has on tendon macroscale mechanics and whether sliding is associated with interfibrillar shear stresses are unknown. Therefore, the objective of this work is to quantify the contribution of interfibrillar sliding on tendon macroscale mechanics by simultaneously measuring the tissue behavior at both length-scales and interpreting the results with a micro-structural shear lag model directly incorporating interfibrillar shear stresses. We hypothesize that the reduced stiffness and increased viscosity observed in the tissue macroscale properties at higher strains are due to increases in interfibrillar sliding and that this behavior is consistent with a shear lag model involving interfibrillar shear stress.

Determination of Stoichiometry of GaAs Component in (Gaas)Ge Epitaxially Grown Thin Films by Electron Microprobe X-Ray Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 264-265
Author(s):  
D. R. Liu ◽  
S. S. Shinozaki ◽  
R. J. Baird
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Compound Semiconductors ◽  
Energy Dispersive Analysis ◽  
X Ray ◽  
Metastable Alloys ◽  
Lower Voltage

The epitaxially grown (GaAs)Ge thin film has been arousing much interest because it is one of metastable alloys of III-V compound semiconductors with germanium and a possible candidate in optoelectronic applications. It is important to be able to accurately determine the composition of the film, particularly whether or not the GaAs component is in stoichiometry, but x-ray energy dispersive analysis (EDS) cannot meet this need. The thickness of the film is usually about 0.5-1.5 μm. If Kα peaks are used for quantification, the accelerating voltage must be more than 10 kV in order for these peaks to be excited. Under this voltage, the generation depth of x-ray photons approaches 1 μm, as evidenced by a Monte Carlo simulation and actual x-ray intensity measurement as discussed below. If a lower voltage is used to reduce the generation depth, their L peaks have to be used. But these L peaks actually are merged as one big hump simply because the atomic numbers of these three elements are relatively small and close together, and the EDS energy resolution is limited.

New approach to Monte Carlo simulation of photon transport in the frequency domain

1995 ◽  
Author(s):  
Ilya V. Yaroslavsky ◽  
Anna N. Yaroslavsky ◽  
Hans-Joachim Schwarzmaier ◽  
Garif G. Akchurin ◽  
Valery V. Tuchin
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Frequency Domain ◽  
New Approach ◽  
Photon Transport
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