Water‐immersion effect on radial crack initiation behavior in a fiber‐bundle‐reinforced epoxy cylinder with graphene in the interfacial region

2018 ◽  
Vol 136 (8) ◽  
pp. 47080
Author(s):  
Kang Yang ◽  
Bin Yang ◽  
Jinling Wang ◽  
Liang He ◽  
Yun Wan ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Fiber Bundle ◽  
Radial Crack ◽  
Water Immersion ◽  
Interfacial Region

Contact Damage in Brittle Curved Coatings: The Influence of Indenter/Coating Modulus Mismatches

2006 ◽  
Vol 312 ◽  
pp. 369-374 ◽  
Author(s):  
Tarek Qasim ◽  
Chris Ford ◽  
Mark Bush ◽  
Xiao Zhi Hu
Keyword(s):  
Crack Initiation ◽  
Damage Evolution ◽  
Radial Crack ◽  
Crack Evolution ◽  
Contact Damage ◽  
Brittle Coating ◽  
Axis Of Symmetry ◽  
Coating Layers ◽  
Polymeric Underlayers ◽  
Radial Cracks

The effects of indenter/coating modulus mismatch on contact damage in bilayer systems composed of brittle coating layers on compliant polymeric underlayers is investigated. Convex specimens having curvature of 12 mm inner coating diameter are produced, and loaded using flat indenters of four different moduli. Glass plates of d = 1 mm thick are used as representative of the brittle coating, and soft epoxy filler is used as an underlayer. Specimens are loaded along the convex axis of symmetry. In this fashion the influence of indenter modulus on radial crack initiation and damage evolution is examined. Previous studies utilised hard spherical indenters of various sizes, and did not consider the effect of a compliant indenter on radial crack evolution and subsequent damage patterns. It is demonstrated that critical loads for initiation of radial cracks and subsequent damage patterns especially at specimen margins are sensitive to indenter modulus (indenter/coating modulus mismatch).

Out-of-plane failure of an ice floe: Radial-crack-initiation-controlled fracture

2015 ◽  
Vol 119 ◽  
pp. 183-203 ◽  
Author(s):  
Wenjun Lu ◽  
Raed Lubbad ◽  
Sveinung Løset
Keyword(s):  
Crack Initiation ◽  
Radial Crack ◽  
Plane Failure ◽  
Out Of Plane ◽  
Controlled Fracture

The Influence of Water Immersion on Skin-Core Debonding in GFRP-Balsa Sandwich Structures

1996 ◽  
Vol 15 (11) ◽  
pp. 1161-1172 ◽  
Author(s):  
W. J. Cantwell ◽  
G. Broster ◽  
P. Davies
Keyword(s):  
Sandwich Structures ◽  
Water Immersion ◽  
Lower Surface ◽  
Interfacial Region ◽  
Test Technique ◽  
Fibre Bridging ◽  
Marine Industry ◽  
Influence Of Water ◽  
Glass Fibre Reinforced ◽  
Pre Treatment

A new test technique has been developed in order to characterise the skincore interfacial properties of a series of fibre reinforced sandwich structures similar to those presently being used in the marine industry. The technique involves peeling the lower surface skin away from the core in a controlled fashion. Four different glass fibre reinforced epoxy/balsa structures have been tested and the effect of incorporating various skin-core interlayers assessed. Tests were also undertaken on specimens that had been immersed in seawater for a period of forty-five days. The results indicate that the fracture energies associated with skin-core debonding are relatively high, typically 1000 J/m2. It has also been shown that neither a pre-treatment of the balsa core nor the incorporation of a layer of CSM fibres resulted in an improvement in the fracture energy of the interfacial region. Immersion in seawater for forty-five days resulted in a significant increase in the fracture toughness of this region. A subsequent examination of the fracture surfaces showed that fibre bridging between the GFRP skin and the balsa core was more extensive in the soaked samples.

Study of Dimensional Changes on Alkali Treated Zallaca Fibre Reinforced Unsaturated Polyester Composites under Different Aqueous Environments

2019 ◽  
Vol 961 ◽  
pp. 3-9
Author(s):  
Dody Ariawan ◽  
Muhamad Faizal Asfar ◽  
Eko Surojo
Keyword(s):  
Sea Water ◽  
Unsaturated Polyester ◽  
Water Immersion ◽  
Fiber Composites ◽  
Flexural Properties ◽  
Interfacial Region ◽  
Distilled Water ◽  
Dimensional Changes ◽  
Molding Method ◽  
Properties Of Composites

In this research, alkali treated zallaca fibre reinforced with high density polyethylene (HDPE) composites are subjected to water immersion tests in order to study the dimensional changes and flexural properties of composites. Composites were frabricated using compression molding method with zallaca fiber content of 30% vt. Composite specimens were immersed under three different solution included distilled water, sea water and acidic solutions for 2 months at room temperature. The highest dimensional changes was recorded for composite immersed in seawater followed by acidic solution and distilled water. The dimensional changes of Zallaca fibre reinforced HDPE in different solution were found to follow a Fickian behaviour. Alkali treated fiber composites after immersion has lower results both in dimensional changes and its slope than untreated fiber composites in different aquaeous environment. The severe degradations are observed by using Scanning Electron Microscopy (SEM) that showed microcracks growth, and degradation of interfacial region between fiber and matrix. Flexural properties of composites decrease after immersion stage in different values.

Radial crack initiation in glass by Vickers indentation

1984 ◽  
Vol 11 (5) ◽  
pp. 443-451 ◽  
Author(s):  
R.Dal maschio ◽  
A. Maddalena ◽  
I. Calliari
Keyword(s):  
Crack Initiation ◽  
Radial Crack ◽  
Vickers Indentation

The influence of heat treatment on the fiber/matrix interface in a SiC-reinforced glassceramic

1988 ◽  
Vol 46 ◽  
pp. 742-743
Author(s):  
E. Bischoff ◽  
O. Sbaizero
Keyword(s):  
Heat Treatment ◽  
Aluminum Silicate ◽  
Lithium Aluminum ◽  
Interfacial Region ◽  
Specimen Preparation ◽  
Crack Wake ◽  
Pull Out ◽  
Annealed Material ◽  
Ultrasonic Drilling ◽  
Fiber Matrix Interface

Fiber or whisker reinforced ceramics show improved toughness and strength. Bridging by intact fibers in the crack wake and fiber pull-out after failure contribute to the additional toughness. These processes are strongly influenced by the sliding and debonding resistance of the interfacial region. The present study examines the interface in a laminated 0/90 composite consisting of SiC (Nicalon) fibers in a lithium-aluminum-silicate (LAS) glass-ceramic matrix. The material shows systematic changes in sliding resistance upon heat treatment.As-processed samples were annealed in air at 800 °C for 2, 4, 8, 16 and 100 h, and for comparison, in helium at 800 °C for 4 h. TEM specimen preparation of as processed and annealed material was performed with special care by cutting along directions having the fibers normal and parallel to the section plane, ultrasonic drilling, dimpling to 100 pm and final ionthinning. The specimen were lightly coated with Carbon and examined in an analytical TEM operated at 200 kV.

Preparation of Electron Transparent Metal-Matrix Composites

1968 ◽  
Vol 26 ◽  
pp. 334-335 ◽  
Author(s):  
M. R. Pinnel ◽  
A. Lawley
Keyword(s):  
Stainless Steel ◽  
Load Transfer ◽  
Volume Fraction ◽  
Steel Wire ◽  
Initial Step ◽  
Interfacial Region ◽  
Matrix Composites ◽  
Specific Test ◽  
The Matrix ◽  
The One

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.

A TEM study of the interface between organic matrix and aragonite in a biological hard tissue, nacre

1992 ◽  
Vol 50 (2) ◽  
pp. 1024-1025
Author(s):  
Jun Liu ◽  
Katie E. Gunnison ◽  
Mehmet Sarikaya ◽  
Ilhan A. Aksay
Keyword(s):  
Mechanical Properties ◽  
Ion Beam ◽  
Laminated Composite ◽  
Organic Matrix ◽  
Pearl Oyster ◽  
Interfacial Structure ◽  
Interfacial Region ◽  
Thin Sections ◽  
Organic Layers ◽  
Transmission Electron

The interfacial structure between the organic and inorganic phases in biological hard tissues plays an important role in controlling the growth and the mechanical properties of these materials. The objective of this work was to investigate these interfaces in nacre by transmission electron microscopy. The nacreous section of several different seashells -- abalone, pearl oyster, and nautilus -- were studied. Nacre is a laminated composite material consisting of CaCO3 platelets (constituting > 90 vol.% of the overall composite) separated by a thin organic matrix. Nacre is of interest to biomimetics because of its highly ordered structure and a good combination of mechanical properties. In this study, electron transparent thin sections were prepared by a low-temperature ion-beam milling procedure and by ultramicrotomy. To reveal structures in the organic layers as well as in the interfacial region, samples were further subjected to chemical fixation and labeling, or chemical etching. All experiments were performed with a Philips 430T TEM/STEM at 300 keV with a liquid Nitrogen sample holder.

Patient Involvement in Treatment Decision Making Can Help or Hinder Placebo Analgesia

2014 ◽  
Vol 222 (3) ◽  
pp. 165-170 ◽  
Author(s):  
Andrew L. Geers ◽  
Jason P. Rose ◽  
Stephanie L. Fowler ◽  
Jill A. Brown
Keyword(s):  
Patient Involvement ◽  
Cold Water ◽  
Prior Experience ◽  
Water Immersion ◽  
Treatment Decision ◽  
Cold Water Immersion ◽  
Not Given ◽  
Placebo Analgesia ◽  
Treatment Decision Making ◽  
Immersion Experience

Experiments have found that choosing between placebo analgesics can reduce pain more than being assigned a placebo analgesic. Because earlier research has shown prior experience moderates choice effects in other contexts, we tested whether prior experience with a pain stimulus moderates this placebo-choice association. Before a cold water pain task, participants were either told that an inert cream would reduce their pain or they were not told this information. Additionally, participants chose between one of two inert creams for the task or they were not given choice. Importantly, we also measured prior experience with cold water immersion. Individuals with prior cold water immersion experience tended to display greater placebo analgesia when given choice, whereas participants without this experience tended to display greater placebo analgesia without choice. Prior stimulus experience appears to moderate the effect of choice on placebo analgesia.

The physiologic effects of hypodynamics induced by water immersion.

1960 ◽  
Author(s):  
D. E. Graveline ◽  
B. Balke
Keyword(s):  
Water Immersion
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