Experimental investigation of fracture toughness KIIC of frozen soil

2000 ◽  
Vol 37 (1) ◽  
pp. 253-258 ◽  
Author(s):  
Hongsheng Li ◽  
Haitian Yang ◽  
Zengli Liu
Keyword(s):  
Fracture Toughness ◽  
Experimental Study ◽  
Experimental Investigation ◽  
Loading Rate ◽  
Fracture Behaviour ◽  
Frozen Soil ◽  
Slight Effect ◽  
Factors Affecting ◽  
Four Point Bending ◽  
Main Factors

This paper describes an experimental study on the fracture toughness KIIC of pure frozen soil and the behaviour of the interface between frozen soil and concrete. A four-point bending device is used in the test. Experimental results indicate that water content and temperature are the main factors affecting fracture toughness. Within the range of the experiment, loading rate has a very slight effect on fracture toughness. Some formulae are suggested to evaluate the fracture behaviour of frozen soil.Key words: frozen soil, fracture mechanics, fracture toughness, interface.

scholarly journals Fracture Toughness of Dense Cordierite: Sintering Cycle Effect

2012 ◽  
Vol 730-732 ◽  
pp. 445-449
Author(s):  
Fernando A. Costa Oliveira ◽  
José Cruz Fernandes ◽  
Julien Schmitt ◽  
Luis Guerra Rosa ◽  
Diamantino Dias
Keyword(s):  
Fracture Toughness ◽  
Fracture Process ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Fracture Behaviour ◽  
Minimum Energy ◽  
Energy Costs ◽  
Fracture Origin ◽  
Four Point Bending ◽  
Microstructure Of The Material

The aim of this work was to analyse the fracture behaviour of commercial dense cordierite bodies sintered in an electrical furnace in static air at 1250°C, 1275°C and 1300°C for 30 min using different cycling schedules in order to obtain tougher materials at minimum energy costs. Using a stereomicroscope and a scanning electron microscope, fracture surfaces of as-sintered bars tested under four-point bending at room temperature were examined at different magnification levels in order to determine the origin of fracture in each sintered bar. Once the fracture origin was identified, it was possible to measure its size, and based on ASTM C1322-96a standard, we were able to estimate the fracture toughness of the sintered parts. Fracture toughness was found to increase with increasing of sintering temperature from 1.8 MPa∙m½ to 3.1 MPa∙m½ by rising the temperature from 1250°C to 1300°C as the fracture process is strongly influenced by the microstructure of the material.

scholarly journals Formation of the voltage pulses up to 400 kilovolts with front pulse less than 10 nanoseconds

2021 ◽  
Vol 2064 (1) ◽  
pp. 012126
Author(s):  
B A Kozlov ◽  
D S Makhanko
Keyword(s):  
Experimental Study ◽  
Operating Voltage ◽  
Basic Information ◽  
Factors Affecting ◽  
X Ray ◽  
Spark Gap ◽  
Metal Ceramic ◽  
Main Factors ◽  
Ceramic Design ◽  
Switching Characteristics

Abstract This work presents basic information about the design, manufacturing technology, and application of small-sized sealed-off spark-gaps in metal-ceramic design with hydrogen filling up to 120 atmospheres at an operating voltage of 100-400 kV with switching energy of up to 10 Joules in pulsed X-ray flaw detectors. The main factors affecting the mechanical strength and stability of the spark-gap operation are described. The results of an experimental study of the switching characteristics of the RO-49 spark gap-sharpeners are presented.

scholarly journals VERIFICATION OF BEHAVIOUR OF HUMAN ENAMEL FOR FRACTURE TOUGHNESS DETERMINATION

2018 ◽  
Vol 58 (4) ◽  
pp. 226 ◽  
Author(s):  
Petra Hájková ◽  
Aleš Jíra ◽  
Luboš Řehounek
Keyword(s):  
Fracture Toughness ◽  
Loading Rate ◽  
Fracture Behaviour ◽  
Fracture Initiation ◽  
Fracture Test ◽  
Indentation Fracture ◽  
Human Enamel ◽  
Reduced Modulus ◽  
The Impact ◽  
Determine Fracture Toughness

<p>Enamel is the hardest biological tissue in the human body because of its structure<br />and composition. The structure of interlocking rods enables this biomaterial to resist the stresses of mastication. Unfortunately, enamel is prone to fracture initiation and growth. Determining fracture toughness of enamel is a difficult task. The lack of thickness makes it impossible to prepare samples which could be analyzed by usual methods. Other authors use Vickers indentation fracture test (VIF) to determine fracture toughness of enamel ordinarily. VIF is, however, not generally acceptable.<br />The aim of this study is verification of fracture behaviour of enamel using nanoindentation. In the study the impact of changes of hardness (HIT) and reduced modulus (Er) caused by crack initiation and growth on fracture toughness determination is observed. The next goal is evaluation of loading rate impact.</p>

The effects of elastane and finishing processes on the performance properties of denim fabrics

2019 ◽  
Vol 31 (2) ◽  
pp. 243-258 ◽  
Author(s):  
Selin Hanife Eryuruk
Keyword(s):  
Experimental Study ◽  
Design Methodology ◽  
Performance Properties ◽  
Content Type ◽  
Factors Affecting ◽  
Fabric Structure ◽  
Aesthetic Appearance ◽  
Main Factors ◽  
And Performance ◽  
Finishing Processes

PurposeThe main factors affecting consumers when selecting denim garments are aesthetic, appearance and fashion. Besides these factors, comfort and performance properties of the denim garments during usage are very important. The purpose of this paper is to determine the effects of different finishing processes on the performance properties of 100 percent cotton and 98 percent cotton+2 percent elastane denim fabrics.Design/methodology/approachThe research design for this study consists of experimental study. In order to evaluate the effects of finishing on the performance properties of fabrics, eight types of fabrics were selected for evaluation. Rigid, resin, bleaching and softening type fabrics with and without elastane were analyzed statistically.FindingsThe results obtained in the study clearly showed that the types of finishing and elastane fiber in the fabric structure had a significant influence on mechanical and comfort properties of denim fabrics.Originality/valueAs a result of the literature review, it was seen that there were limited studies concerning mechanical, functional and comfort properties of denim fabrics together. In this study, the effects of finishing processes on the tear strength, stiffness, drape, mechanical and thermal comfort characteristics were deeply evaluated.

scholarly journals Experimental study on the thermal performance of an air conditioning system in a pure electric vehicle

2021 ◽  
pp. 93-93
Author(s):  
Enhai Liu ◽  
Haijun Li ◽  
Yajun Gong ◽  
Yuping Wei ◽  
Haifei Chen
Keyword(s):  
Experimental Study ◽  
Electric Vehicle ◽  
Heat Pump ◽  
Thermal Performance ◽  
Air Conditioning ◽  
Air Conditioning System ◽  
Factors Affecting ◽  
Discharge Temperature ◽  
Heating Capacity ◽  
Main Factors

This paper studies the thermal performance of an air conditioning system in a pure electric vehicle. An experiment is designed to examine the main factors affecting the performance, and the experimental results show that a heat pump with a low-pressure gas-mixing system can increase the heating capacity and decrease the discharge temperature.

Response of anchors to variations in displacement-based loading

2003 ◽  
Vol 40 (3) ◽  
pp. 694-701 ◽  
Author(s):  
Ashraf Ghaly ◽  
Adel Hanna
Keyword(s):  
Experimental Investigation ◽  
Strain Rate ◽  
Loading Rate ◽  
Dense Medium ◽  
Displacement Rate ◽  
Time To Failure ◽  
Pullout Capacity ◽  
Slight Effect ◽  
Pullout Load ◽  
Displacement Based

The results of an experimental investigation on the effect of variations in displacement-based loading on the pullout capacity of anchors are presented. A single-pitch, screw helical anchor was used in the testing. The tests were conducted in dry, well-graded, dense, medium, and loose sands with relative densities of 79, 47, and 19%, respectively. Anchors were installed to, and tested at, shallow and deep depths. Measurements of ultimate pullout load and displacement at failure were made. The values of time-to-failure and mean loading rate were calculated and presented. The results of this study show that variations of displacement-based loading had some effect on the pullout capacity of shallow anchors but had only a slight effect on deep anchors. For a given depth of installation and a given sand state, the ultimate pullout load of an anchor decreases with increasing loading rate. This effect was more pronounced in anchors installed to shallow depths.Key words: anchors, displacement, displacement rate, pullout capacity, strain rate, sand, foundations, uplift.

Recent Rapid Climate Changes in Antarctic and their Influence on Low Diversity Ecosystems

2010 ◽  
Vol 17 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Katarzyna J. Chwedorzewska
Keyword(s):  
Environmental Variables ◽  
Climate Changes ◽  
Biological Significance ◽  
Global Changes ◽  
Factors Affecting ◽  
Low Diversity ◽  
Main Factors ◽  
The Antarctic ◽  
High Diversity ◽  
Temperature Water

ABSTRACTThe geographic position, astronomic factors (e.g. the Earth’s maximum distance from the Sun during winter), ice cover and altitude are the main factors affecting the climate of the Antarctic, which is the coldest place on Earth. Parts of Antarctica are facing the most rapid rates of anthropogenic climate change currently seen on the planet. Climate changes are occurring throughout Antarctica, affecting three major groups of environmental variables of considerable biological significance: temperature, water, UV-B radiation.Low diversity ecosystems are expected to be more vulnerable to global changes than high diversity ecosystems

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