The tensile force oscillation of polycarbonate at elevated temperatures

2012 ◽  
Vol 53 (3) ◽  
pp. 589-596 ◽  
Author(s):  
Donyau Chiang ◽  
Meng-Leung Tsai ◽  
Sanboh Lee
Keyword(s):  
Elevated Temperatures ◽  
Tensile Force ◽  
Force Oscillation

scholarly journals Modelling tensile force oscillation during the tensile test of PET specimens

2009 ◽  
Vol 3 (2) ◽  
pp. 63-69 ◽  
Author(s):  
L. M. Vas ◽  
F. Ronkay ◽  
T. Czigany
Keyword(s):  
Tensile Test ◽  
Tensile Force ◽  
Force Oscillation

scholarly journals Experimental investigation and analytical modeling of the crack width effect on the fire performance of carbon textile-reinforced concrete composite

2021 ◽  
Vol 15 (3) ◽  
pp. 81-92
Author(s):  
Tran Manh Tien ◽  
Xuan Hong Vu ◽  
Emmanuel Ferrier ◽  
Pham Duc Tho ◽  
Bui Thi Loan
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Strength ◽  
Crack Width ◽  
Analytical Modeling ◽  
Elevated Temperatures ◽  
Thermal Protection ◽  
Tensile Force ◽  
Fire Performance ◽  
Textile Reinforced Concrete ◽  
Cementitious Matrix

In comparison with fiber-reinforced polymer (FRP) composite, the textile-reinforced concrete (TRC) presents stability in mechanical performance at elevated temperatures thanks to a thermal protection layer by the cementitious matrix. This paper presents the experimental characterization and analytical modeling for fire performance of carbon TRC under the thermomechanical regime at constant tensile force. The carbon TRC is manufactured from the cementitious matrix with good thermal properties (refractory matrix) and the reinforcement of carbon textiles. In the experiment, the ultimate strength of the carbon TRC specimen was firstly identified from the direct tensile tests at ambient temperature. Afterwards, in the thermomechanical regime, the fire performance of carbon TRC specimens according to 5 loading levels ranging from 10% to 75% related to its ultimate strength was determined. As a result, the effect of crack appearance on this thermomechanical performance was highlighted and analyzed. For the analytical modeling, a model was calibrated with the experimental results to predict the fire performance of carbon TRC by taking into account the effect of crack width.

Global Buckling of a Pre-Pressurized Flexible Flowline

2013 ◽  
Author(s):  
Zhengmao Yang ◽  
Daniel Karunakaran
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Elevated Temperatures ◽  
Tensile Force ◽  
Flexible Pipe ◽  
Upheaval Buckling ◽  
Axial Tension ◽  
Lateral Resistance ◽  
Rock Cover ◽  
Global Buckling

For the protection from object drop/fishing trawl impact, flexible flowline is normally trenched or rock-dumped. And hence, upheaval buckling is promoted by the elevated temperatures and high pressures. In order to reduce the rock cover requirement for mitigation of upheaval buckling, rock-dumping or trenching while the flexible pipe are pressurized has been performed successfully in several north sea projects. The temperature and pressure induced elongation of flexible pipe are design dependent. For high pressure flexible flowline, the pressure expansion is significantly higher than conventional rigid pipelines. Due to the low bending stiffness and high pressure expansion, a flexible flowline will buckle laterally when it is pre-pressurized in hydro-test before trenching or rock-dumping. As a consequence, lateral imperfections are induced and will be kept after trenching or rock-dumping due to lateral resistance and bending stress relaxation of the flowline. In these locations, the flowline tends to deform laterally in operating. On the other hand, when the flowline is de-pressurized after trenching or rock-dumping the contraction of the flowline is restrained by the surrounding soils or rocks, and hence axial tension force can be obtained. When the flowline starts to operate, this tensile force will neutralize part of the compressive axial force, and therefore the required upheaval resistance is reduced. In this paper, global buckling of a pre-pressurized flexible flowline has been studied, and the influence on the requirement of rock covers is presented.

MECHANICAL PROPERTIES OF STRUCTURAL STEEL AND HIGH-TENSION BOLT AT ELEVATED TEMPERATURE

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Kyung-Jae Shin ◽  
Hee-Du Lee ◽  
So-Yeong Kim ◽  
Da-Som Chu ◽  
Jong-Hun Woo
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Yield Strength ◽  
Structural Steel ◽  
Elevated Temperatures ◽  
Residential Buildings ◽  
Tensile Force ◽  
Test Results ◽  
Steel Members ◽  
Reduction Factors

This paper presents the test results of the mechanical properties of three types of structural steel at high temperature, which are generally used for the Pre-Engineered Building (PEB) system. The PEB system is generally used for non-residential buildings, such as factories and warehouses. The structural steel members are installed without fire resistance protection, which means they are very weak in the case of fire. The end-plate connection could be critical in the case of fire because most of the moment is resisted by the tensile force of the bolts. Therefore, the mechanical properties of bolts at elevated temperatures are tested. Coupon test specimens for SS400(SS275), SM490(SS355), and F10T bolts were tested according to ASTM E8M. The high-temperature coupon tests were performed at 20°C, 400°C, 500°C, 600°C, 700°C, and 800°C. The test results were compared with the design reduction factors obtained from the American and European standards. The yield strength and tensile strength satisfied the minimum strength of the specified standards at 20°C. However, the reduction factor for yield strength obtained at a high temperature was lower than that of the standard value suggested by the code. In particular, the reduction factors for the high-strength bolt (F10T) were lower than those of the structural steel members (SS400(SS275), SM490(SM355)).

Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 142-143
Author(s):  
N. M. P. Low ◽  
L. E. Brosselard
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Elevated Temperatures ◽  
Stoichiometric Composition ◽  
Rare Earth Ions ◽  
Crystalline Solid ◽  
Precipitation Process ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Rare Earth Fluorides

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

Electron microscopy of crystalline structure in thermotropic random copolymers

1991 ◽  
Vol 49 ◽  
pp. 1054-1055
Author(s):  
Afzana Anwer ◽  
S. Eilidh Bedford ◽  
Richard J. Spontak ◽  
Alan H. Windle
Keyword(s):  
Electron Microscopy ◽  
Crystalline Structure ◽  
Liquid Crystalline ◽  
Elevated Temperatures ◽  
Random Copolymers ◽  
Molecular Characteristics ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Identical Monomer ◽  
Periodic Layer

Random copolyesters composed of wholly aromatic monomers such as p-oxybenzoate (B) and 2,6-oxynaphthoate (N) are known to exhibit liquid crystalline characteristics at elevated temperatures and over a broad composition range. Previous studies employing techniques such as X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) have conclusively proven that these thermotropic copolymers can possess a significant crystalline fraction, depending on molecular characteristics and processing history, despite the fact that the copolymer chains possess random intramolecular sequencing. Consequently, the nature of the crystalline structure that develops when these materials are processed in their mesophases and subsequently annealed has recently received considerable attention. A model that has been consistent with all experimental observations involves the Non-Periodic Layer (NPL) crystallite, which occurs when identical monomer sequences enter into register between adjacent chains. The objective of this work is to employ electron microscopy to identify and characterize these crystallites.

Generation of 4H and 6H Structures During the Hexagonal-Rhombohedral Transformation in Dy2Co17

1975 ◽  
Vol 33 ◽  
pp. 38-39
Author(s):  
C. W. Allen ◽  
D. L. Kuruzar
Keyword(s):  
Elevated Temperatures ◽  
Layer Structure ◽  
Transition Element ◽  
Temperature Structure ◽  
Allotropic Transformation ◽  
Layer Plane ◽  
Planar Defects ◽  
Topologically Close Packed ◽  
Transformation Mechanisms ◽  
Shear Transformation

The rare earth/transition element intermetallics R2T17 are essentially topologically close packed phases for which layer structure models have already been presented. Many of these compounds are known to undergo allotropic transformation of the type at elevated temperatures. It is not unexpected that shear transformation mechanisms are involved in view of the layering character of the structures. The transformations are evidently quite sluggish, illustrated in furnace cooled Dy2Co17 by the fact that only rarely has the low temperature rhombohedral form been seen. The more usual structures observed so far in furnace cooled alloys include 4H and 6H in Dy2Co17 (Figs. 1 and 2) . In any event it is quite clear that the general microstructure is very complicated as a consequence of the allotropy, illustrated in Fig. 3. Numerous planar defects in the layer plane orientation are evident as are non-layer plane defects inherited from a high temperature structure.

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