Role of core support material in veneer failure of brittle layer structures

2007 ◽  
Vol 82B (1) ◽  
pp. 115-121 ◽  
Author(s):  
Ilja Hermann ◽  
Sanjit Bhowmick ◽  
Brian R. Lawn
Keyword(s):  
Support Material ◽  
Layer Structures ◽  
Brittle Layer

Role of Adhesive Interlayer in Transverse Fracture of Brittle Layer Structures

2000 ◽  
Vol 15 (4) ◽  
pp. 1017-1024 ◽  
Author(s):  
Herzl Chai ◽  
Brian Lawn
Keyword(s):  
Crack Initiation ◽  
Glass Surface ◽  
Hard Spheres ◽  
Glass Plate ◽  
Critical Conditions ◽  
Transverse Fracture ◽  
Adhesive Interlayer ◽  
Layer Structures ◽  
Brittle Layer

The role of a soft adhesive interlayer in determining critical conditions for fracture in brittle layer structures from indentation with hard spheres is investigated. A model transparent trilayer system consisting of a glass plate overlayer (thickness range 80 μm to 2 mm) joined to a glass plate underlayer (thickness 5.6 mm) by an epoxy adhesive (thickness range 5 μm to 8 mm), loaded at its top surface with a hard tungsten carbide sphere (radius 3.96 mm), facilitatesin situobservations of the crack initiation and propagation. Whereas in bulk glass fracture occurs by inner Hertzian cone cracking immediately outside the contact circle, the soft adhesive allows the overlayer glass plate to flex, initiating additional transverse fracture modes within the overlayer: downward-extending outer ring cracks at the top glass surface well outside the contact, and upward-extending radial cracks at the bottom glass surface (i.e., at the glass/adhesive interface) on median planes containing the contact axis. The top and bottom surfaces of the glass overlayers are given selective prebonding abrasion treatments to ensure uniform flaw states, so as to enable accurate comparisons between crack initiation conditions. The adhesive bonding is strong enough to preclude delamination in our layer system. Of the three transverse crack systems, the subsurface radials generates most easily in systems with large adhesive thicknesses (and smaller overlayer thicknesses). Semi-empirical relations are specified for the dependence of the critical loads for radial and ring cracking on adhesive as well as overlayer thickness, based on the assumption that crack initiation occurs when the maximum tensile stresses in the flexing glass plate exceed the bulk strength of the (abraded) glass. Coupled with the traditional “Auerbach's law” for cone crack initiation, these relations afford a basis for the construction of simple design diagrams for brittle layer systems joined by adhesives.

Role of indenter material and size in veneer failure of brittle layer structures

2007 ◽  
Vol 82B (1) ◽  
pp. 253-259 ◽  
Author(s):  
Sanjit Bhowmick ◽  
Juan José Meléndez-Martínez ◽  
Ilja Hermann ◽  
Yu Zhang ◽  
Brian R. Lawn
Keyword(s):  
Layer Structures ◽  
Brittle Layer

On velocity gradient dynamics and turbulent structure

2015 ◽  
Vol 780 ◽  
pp. 60-98 ◽  
Author(s):  
J. M. Lawson ◽  
J. R. Dawson
Keyword(s):  
Velocity Gradient ◽  
Local Strain ◽  
Turbulent Structure ◽  
Stochastic Estimation ◽  
Spatially Resolved ◽  
Gradient Dynamics ◽  
Layer Structures ◽  
Non Local ◽  
Conditional Averaging

The statistics of the velocity gradient tensor $\unicode[STIX]{x1D63C}=\boldsymbol{{\rm\nabla}}\boldsymbol{u}$, which embody the fine scales of turbulence, are influenced by turbulent ‘structure’. Whilst velocity gradient statistics and dynamics have been well characterised, the connection between structure and dynamics has largely focused on rotation-dominated flow and relied upon data from numerical simulation alone. Using numerical and spatially resolved experimental datasets of homogeneous turbulence, the role of structure is examined for all local (incompressible) flow topologies characterisable by $\unicode[STIX]{x1D63C}$. Structures are studied through the footprints they leave in conditional averages of the $Q=-\text{Tr}(\unicode[STIX]{x1D63C}^{2})/2$ field, pertinent to non-local strain production, obtained using two complementary conditional averaging techniques. The first, stochastic estimation, approximates the $Q$ field conditioned upon $\unicode[STIX]{x1D63C}$ and educes quantitatively similar structure in both datasets, dissimilar to that of random Gaussian velocity fields. Moreover, it strongly resembles a promising model for velocity gradient dynamics recently proposed by Wilczek & Meneveau (J. Fluid Mech., vol. 756, 2014, pp. 191–225), but is derived under a less restrictive premise, with explicitly determined closure coefficients. The second technique examines true conditional averages of the $Q$ field, which is used to validate the stochastic estimation and provide insights towards the model’s refinement. Jointly, these approaches confirm that vortex tubes are the predominant feature of rotation-dominated regions and additionally show that shear layer structures are active in strain-dominated regions. In both cases, kinematic features of these structures explain alignment statistics of the pressure Hessian eigenvectors and why local and non-local strain production act in opposition to each other.

Role of the support material on laser desorption/ionization mass spectra

2008 ◽  
Vol 22 (7) ◽  
pp. 925-929 ◽  
Author(s):  
A. Gruszecka ◽  
M. Szymanska-Chargot ◽  
A. Smolira ◽  
J. Cytawa ◽  
L. Michalak
Keyword(s):  
Mass Spectra ◽  
Laser Desorption ◽  
Ionization Mass ◽  
Support Material ◽  
Laser Desorption Ionization ◽  
Desorption Ionization

Overview: Damage in brittle layer structures from concentrated loads

2002 ◽  
Vol 17 (12) ◽  
pp. 3019-3036 ◽  
Author(s):  
Brian R. Lawn ◽  
Yan Deng ◽  
Pedro Miranda ◽  
Antonia Pajares ◽  
Herzl Chai ◽  
...  
Keyword(s):  
Damage Mechanics ◽  
Limiting Factors ◽  
Damage Initiation ◽  
Layer Structures ◽  
Brittle Layer ◽  
Wide Range ◽  
Damage Process ◽  
Analytical Relations ◽  
System Variables ◽  
Process Damage

In this article, we review recent advances in the understanding and analysis of damage initiation and evolution in laminate structures with brittle outerlayers and compliant sublayers in concentrated loading. The relevance of such damage to lifetime-limiting failures of engineering and biomechanical layer systems is emphasized. We describe the results of contact studies on monolayer, bilayer, trilayer, and multilayer test specimens that enable simple elucidation of fundamental damage mechanics and yet simulate essential function in a wide range of practical structures. Damage processes are observed usingpost mortem(“bonded-interface”) sectioning and directin situviewing during loading. The observations reveal a competition between damage modes in the brittle outerlayers—cone cracks or quasiplasticity at the top (near-contact) surfaces and laterally extending radial cracks at the lower surfaces. In metal or polymeric support layers, yield or viscoelasticity can become limiting factors. Analytical relations for the critical loads to initiate each damage mode are presented in terms of key system variables: geometrical (layer thickness and indenter radius); material (elastic modulus, strength and toughness of brittle components, hardness of deformable components). Such relations provide a sound physical basis for the design of brittle layer systems with optimal damage thresholds. Other elements of the damage process—damage evolution to failure, crack kinetics (and fatigue), flaw statistics, and complex (tangential) loading—are also considered.

scholarly journals Duties and Powers of The Department of Public Works and Spatial Planning in The Implementation of Road in Kendal

2018 ◽  
Vol 1 (3) ◽  
pp. 785
Author(s):  
Nabella Maharani Novanta
Keyword(s):  
Local Government ◽  
Spatial Planning ◽  
Legal Theory ◽  
Public Works ◽  
Support Material ◽  
Legal Research ◽  
The Road ◽  
Research Activities ◽  
Research Problems

This study discusses the role of the Department of Public Works and Spatial Planning in the implementation of the road in Kendal. Here is more towards the implementation of the supervision. Research problems concerning form of oversight, relations with relevant institutions, as well as the obstacles faced by the Department of Public Works and Spatial in Kendal. To answer these problems required legal research activities, using empirical juridical approach. Sources of data obtained through interviews with sources as well as legislation, legal theory, and the opinions of the leading scholars as support material, and then analyze it in order to get an answer scientifically.Keywords: Local Government; Roads Implementation; Monitoring.

Effect of off-axis concentrated loading on failure of curved brittle layer structures

2006 ◽  
Vol 76B (2) ◽  
pp. 334-339 ◽  
Author(s):  
Tarek Qasim ◽  
Christopher Ford ◽  
Mark B. Bush ◽  
Xiaozhi Hu ◽  
Brian R. Lawn
Keyword(s):  
Layer Structures ◽  
Brittle Layer ◽  
Concentrated Loading

Layer Structures. 4. Role of Long Alkane Spacers in Poly(ester imide)s Derived fromN-(4‘-Hydroxyphenyl)-4-hydroxyphthalimide

1996 ◽  
Vol 29 (12) ◽  
pp. 4234-4240 ◽  
Author(s):  
Hans R. Kricheldorf ◽  
Nicolas Probst ◽  
Gert Schwarz ◽  
Christoph Wutz
Keyword(s):  
Layer Structures

Metastability in SiGe/Si Strained-Layer Structures

1988 ◽  
Vol 116 ◽  
Author(s):  
Brian W. Dodson
Keyword(s):  
Experimental Data ◽  
Plastic Deformation ◽  
Crystal Growth ◽  
Strain Relaxation ◽  
Dislocation Dynamics ◽  
Strained Layer ◽  
Layer Structures ◽  
Standard Models ◽  
Stability Limits

AbstractThe physics governing growth and stability properties in SiGe/Si strainedlayer structures is reviewed. The role of metastability in crystal growth is outlined. Experimental data on stability limits and rates of strain relaxation are examined. We conclude that essentially all observations on relaxation of semiconductor strained-layer structures can be explained by standard models of plastic deformation adapted to the special conditions controlling dislocation dynamics in these structures.

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