The finite-amplitude instability in the folding of layered rocks

1970 ◽  
Vol 7 (2) ◽  
pp. 457-466 ◽  
Author(s):  
William M. Chapple
Keyword(s):  
Strain Rate ◽  
Effective Viscosity ◽  
Early Stage ◽  
Surrounding Medium ◽  
Single Layer ◽  
Finite Amplitude ◽  
Internal Stresses ◽  
Second Development ◽  
Medium System ◽  
Shortening Rate

Examination and comparison of several computational studies of finite-amplitude single-layer folding bring to light an important unifying concept, that of the finite-amplitude instability. If the fold-causing stresses are constant throughout the development of a fold, the overall shortening strain-rate due to the folding will first show a marked increase with increasing fold amplitude and then decrease as the fold becomes tightly appressed; on the other hand, if the shortening strain-rate is held constant, the stresses necessary to maintain the constant shortening rate will decrease and then increase again. Considering the layer-in-medium system as a whole, this instability results in a bulk-effective viscosity with respect to layer-parallel compression, which is first high, then decreases to a minimum, and then rises again, These changes in bulk-effective viscosity are large, nearly two orders of magnitude.Effects of the finite-amplitude instability on the internal stresses within the layer and surrounding medium are as follows. First, there will probably be an early, low-amplitude stage with high layer-parallel stresses within the competent layer. The major development of deformation fabrics may occur during (his early stage. Second, development of plastic yield in the crestal region of the fold is strongly controlled by the details of external load pattern and therefore by the mechanism causing the folding. Third, the increase in effective bulk viscosity of the layer-in-medium system corresponds to a major rearrangement of the deformation patterns in both the medium and the layer.Consideration of décollement folding and multi-layer folding suggests that the concept of finite-amplitude instability may be applicable, at least qualitatively, to these more common fold types. If this is true, then the concept is important in considering more general geologic questions such as the dating of an orogenic episode by angular unconformity.

scholarly journals Finite Element Prediction for the Internal Stresses of (Ti,Al)N Coatings

2016 ◽  
Vol 61 (1) ◽  
pp. 149-152 ◽  
Author(s):  
L.W. Żukowska ◽  
A. Śliwa ◽  
J. Mikuła ◽  
M. Bonek ◽  
W. Kwaśny ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Computer Simulation ◽  
Finite Element ◽  
Experimental Studies ◽  
Single Layer ◽  
Internal Stresses ◽  
Pvd Coatings ◽  
Properties Of Coatings ◽  
Gradient Coatings ◽  
Element Method

The general topic of this paper is the computer simulation with use of finite element method (FEM) for determining the internal stresses of selected gradient and single-layer PVD coatings deposited on the sintered tool materials, including cemented carbides, cermets and Al2O3+TiC type oxide tool ceramics by cathodic arc evaporation CAE-PVD method. Developing an appropriate model allows the prediction of properties of PVD coatings, which are also the criterion of their selection for specific items, based on the parameters of technological processes. In addition, developed model can to a large extent eliminate the need for expensive and time-consuming experimental studies for the computer simulation. Developed models of internal stresses were performed with use of finite element method in ANSYS environment. The experimental values of stresses were calculated using the X-ray sin2ψ technique. The computer simulation results were compared with the experimental results. Microhardness and adhesion as well as wear range were measured to investigate the influence of stress distribution on the mechanical and functional properties of coatings. It was stated that occurrence of compressive stresses on the surface of gradient coating has advantageous influence on their mechanical properties, especially on microhardness. Absolute value reduction of internal stresses in the connection zone in case of the gradient coatings takes profitably effects on improvement the adhesion of coatings. It can be one of the most important reasons of increase the wear resistance of gradient coatings in comparison to single-layer coatings.

scholarly journals The role of positively charge poly-L-lysine in the formation of high yield gold nanoplates on the surface for plasmonic sensing application

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259730
Author(s):  
Marlia Morsin ◽  
Suratun Nafisah ◽  
Rahmat Sanudin ◽  
Nur Liyana Razali ◽  
Farhanahani Mahmud ◽  
...  
Keyword(s):  
Substrate Surface ◽  
Surrounding Medium ◽  
Resonance Effect ◽  
Maximum Yield ◽  
Single Layer ◽  
Localized Surface Plasmon ◽  
High Yield ◽  
Synthesis Process ◽  
Wavelength Shift ◽  
Plasmonic Sensor

An anisotropic structure, gold (Au) nanoplates was synthesized using a two-step wet chemical seed mediated growth method (SMGM) directly on the substrate surface. Prior to the synthesis process, poly-l-lysine (PLL) as a cation polymer was used to enhance the yield of grown Au nanoplates. The electrostatic interaction of positive charged by PLL with negative charges from citrate-capped gold nanoseeds contributes to the yield increment. The percentage of PLL was varied from 0% to 10% to study the morphology of Au nanoplates in term of shape, size and surface density. 5% PLL with single layer treatment produce a variety of plate shapes such as hexagonal, flat rod and triangular obtained over the whole substrate surface with the estimated maximum yield up to ca. 48%. The high yield of Au nanoplates exhibit dual plasmonic peaks response that are associated with transverse and longitudinal localized surface plasmon resonance (TSPR and LSPR). Then, the PLL treatment process was repeated twice resulting the increment of Au nanoplates products to ca. 60%. The thin film Au nanoplates was further used as sensing materials in plasmonic sensor for detection of boric acid. The anisotropic Au nanoplates have four sensing parameters being monitored when the medium changes, which are peak position (wavelength shift), intensity of TSPR and LSPR, and the changes on sensing responses. The sensor responses are based on the interaction of light with dielectric properties from surrounding medium. The resonance effect produces by a collection of electron vibration on the Au nanoparticles surface after hit by light are captured as the responses. As a conclusion, it was found that the PLL treatment is capable to promote high yield of Au nanoplates. Moreover, the high yield of the Au nanoplates is an indication as excellent candidate for sensing material in plasmonic sensor.

The Structure and Mechanical Properties of Multilayer Metal-Carbon Coatings Deposited in Pulse Plasma of Arc Discharge

2018 ◽  
Vol 781 ◽  
pp. 53-57 ◽  
Author(s):  
D.G. Piliptsou ◽  
Alexander V. Rogachev ◽  
Alexander Rudenkov ◽  
Ekaterina Kulesh ◽  
Alexander Luchnikov
Keyword(s):  
Heat Treatment ◽  
Friction Coefficient ◽  
Arc Discharge ◽  
Single Layer ◽  
Internal Stresses ◽  
Multilayer Systems ◽  
Carbon Coatings ◽  
Tribotechnical Properties ◽  
Metal Layers ◽  
Multilayer Metal

The influence of the architecture of multilayer metal-carbon coatings, the nature of individual metallic layers (Ti, Cu), heat treatment parameters on their microhardness, the level of internal stresses and tribotechnical properties are determined. It is defined that for systems based on carbon and nanosized metal layers, the friction coefficient values are lower than for single-layer carbon coatings. Heat treatment of multilayer systems in air leads to the increase in the friction coefficient, primarily Ti/a-C/Ti coatings, which is due to the formation of solid phases of TiN, TiC and TiCN, as well as oxides of TixOy acting as abrasive. The level of internal stresses of multilayer systems containing layers of copper is lower than that of single-layer carbon coatings and coatings containing layers of titanium.

scholarly journals Strain Rate Contribution due to Dynamic Recovery of Ultrafine-Grained Cu–Zr as Evidenced by Load Reductions during Quasi-Stationary Deformation at 0.5 Tm

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1150 ◽  
Author(s):  
Wolfgang Blum ◽  
Jiři Dvořák ◽  
Petr Král ◽  
Philip Eisenlohr ◽  
Vaclav Sklenička
Keyword(s):  
Strain Rate ◽  
Dynamic Recovery ◽  
Tensile Deformation ◽  
Coarse Grained ◽  
Internal Stresses ◽  
Back Flow ◽  
Stationary Rate ◽  
Ultrafine Grained ◽  
High Fraction ◽  
And Storage

During quasi-stationary tensile deformation of ultrafine-grained Cu-0.2 mass%Zr at 673 K and a deformation rate of about e - 4 / s load changes were performed. Reductions of relative load by more than about 25% initiate anelastic back flow. Subsequently, the creep rate turns positive again and goes through a relative maximum. This is interpreted by a strain rate component ϵ ˙ - associated with dynamic recovery of dislocations. Back extrapolation indicates that ϵ ˙ - contributes the same fraction of ( 20 ± 10 ) % to the quasi-stationary strain rate that has been reported for coarse-grained materials with high fraction of low-angle boundaries; this suggests that dynamic recovery of dislocations is generally mediated by boundaries. The influence of anelastic back flow on ϵ ˙ - is discussed. Comparison of ϵ ˙ - to the quasi-stationary rate points to enhancement of dynamic recovery by internal stresses. Subtraction of ϵ ˙ - from the total rate yields the rate component ϵ ˙ + related with generation and storage of dislocations; its activation volume is in the order expected from the classical theory of thermal glide.

Tolerable ranges of fluid shear for early life-stage fishes: implications for safe fish passage at hydropower and irrigation infrastructure

2019 ◽  
Vol 70 (11) ◽  
pp. 1503 ◽  
Author(s):  
Anna Navarro ◽  
Craig A. Boys ◽  
Wayne Robinson ◽  
Lee J. Baumgartner ◽  
Brett Miller ◽  
...  
Keyword(s):  
Strain Rate ◽  
Larval Fish ◽  
Early Stage ◽  
Life Stage ◽  
Early Life Stage ◽  
Fish Passage ◽  
Strain Rates ◽  
Fluid Shear ◽  
Murray Cod ◽  
Irrigation Infrastructure

Egg and larval fish drifting downstream are likely to encounter river infrastructure leading to mortality. Elevated fluid shear is one likely cause. To confirm this and determine tolerable strain rates resulting from fluid shear, egg and larvae of three Australian species were exposed to a high-velocity, submerged jet in a laboratory flume. Mortality was modelled over a broad range of strain rates, allowing critical thresholds to be estimated. Eggs were very susceptible to mortality at low strain rates and 100% of golden and silver perch died once strain rate exceeded 629 and 148s–1 respectively. Larvae were less vulnerable than eggs, but mortality increased at higher strain rates and at younger ages. Most ages of larvae will be protected if strain rate does not exceed 600s–1, although a lower guideline of less than 400s–1 may be needed in areas where very early stage Murray cod larvae drift. Golden perch and silver perch were not susceptible to shear once maturity reached ~25 days post-hatch (nearing juvenile metamorphosis). The thresholds described here will prove useful when refining design and operational guidelines for hydropower and irrigation infrastructure to improve fish survival.

Effect of Stress-induced Magnetic Anisotropy on the Properties of Giant Magnetostrictive Single Layer and Multilayer Thin Films

2004 ◽  
Vol 855 ◽  
Author(s):  
J. H. Tan ◽  
V. H. Guerrero ◽  
R. C. Wetherhold ◽  
W. A. Anderson
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Rf Sputtering ◽  
Single Layer ◽  
Annealing Treatment ◽  
Deposition Process ◽  
Vacuum System ◽  
Internal Stresses ◽  
Sensors And Actuators

ABSTRACTGiant magnetostrictive thin films deposited on nonmagnetic substrates can constitute effective sensors and actuators for microdevices. In this work, we investigated the effects of a stress-induced anisotropy on the magnetic properties of Tb0.4Fe0.6, Fe0.5Co0.5 single layer films and [Tb0.4Fe0.6/Fe0.5Co0.5]n multilayers deposited on Si substrates. The magnetostrictive thin films were fabricated by means of RF sputtering and were subjected to a post-deposition annealing treatment. The uniaxial magnetic anisotropy was induced by bending the substrate before deposition and then allowing it to resume its original flat shape after depositing the film. The heat treatment was performed in a vacuum system with a vacuum of 10−6 Torr. The magnetic properties of the fabricated specimens were measured using a SQUID. SEM and XRD analyses were performed to ensure that the thermal treatment would relax the internal stresses induced during the deposition process without crystallizing the film. The thickness of the single layer thin films studied was between 300 and 800 nm while multilayer samples consisted of 6 layers with each layer thickness ranged from about 20 to 40 nm. Compared to single layer samples, multilayer samples with stress anneal growth exhibited an improvement in magnetic saturation by a factor of two while maintaining a low coercive field. Manipulations of the magnitude and direction of magnetic anisotropy was observed by introducing various values of tensile and compressive stress into the film.

scholarly journals Cyclic deformation behaviour and stability of grain-refined 301LN austenitic stainless structure

2018 ◽  
Vol 165 ◽  
pp. 06005 ◽  
Author(s):  
Jiří Man ◽  
Antti Järvenpää ◽  
Matias Jaskari ◽  
Ivo Kuběna ◽  
Stanislava Fintová ◽  
...  
Keyword(s):  
Strain Rate ◽  
Volume Fraction ◽  
Early Stage ◽  
Low Cycle Fatigue ◽  
Deformation Behaviour ◽  
Polarized Light ◽  
Constant Strain Rate ◽  
Coarse Grained ◽  
Grain Sizes ◽  
Cyclic Straining

Low cycle fatigue (LCF) behaviour of metastable austenitic 301LN stainless steel with different grain sizes – coarse-grained (13 μm), fine-grained (1.4 μm) and ultrafine-grained (0.6 μm) – produced by reversion annealing after prior cold rolling was investigated. Fully symmetrical LCF tests with constant total strain amplitudes of 0.5% and 0.6% were performed at room temperature with a low constant strain rate of 2×10-3 s-1. Microstructural changes in different positions within the gauge part of the specimens were examined by optical microscopy (polarized light) and electron backscatter diffraction (EBSD) technique; for quantitative assessment of the volume fraction of deformation induced martensite (DIM) a Feritscope FMP 30 was adopted. The cyclic stress-strain response and specific changes of hysteresis loop shapes in the very early stage of cycling are confronted with the character of DIM formation and its distribution in the whole volume of the material. A possible effect of strain rate (frequency of cycling) on the destabilization of austenitic structure during cyclic straining of materials with different grain sizes is highlighted.

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