LEAK-BEFORE-BREAK CONDITIONS OF PLATES AND PIPES UNDER HIGH FATIGUE STRESSES

Abstract UNS G62100 is a tough, shock resisting, case-hardening chromium-vanadium steel. It has high fatigue resistance in the heat treated condition. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SA-458. Producer or source: Alloy steel mills and foundries.

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LUCEFIN GROUP 20NiCrMo2-2(1.6523), 20NiCrMoS2-2 (1.6526)

Alloy Digest ◽

10.31399/asm.ad.sa0866 ◽

2020 ◽

Vol 69 (12) ◽

Keyword(s):

Wear Resistance ◽

Fatigue Strength ◽

Physical Properties ◽

Tensile Properties ◽

Heat Treating ◽

Medium Size ◽

Case Hardening ◽

Low Carbon ◽

High Fatigue

Abstract Lucefin Group 20NiCrMo2-2 and 20NiCrMoS2-2 are low-carbon, Ni-Cr-Mo, alloy case-hardening steels that are used in the carburized or carbonitrided, and subsequently quench hardened and tempered, condition. These steels are, in general, used for medium-size case-hardened parts requiring high fatigue strength and wear resistance. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, and joining. Filing Code: SA-866. Producer or source: Lucefin S.p.A..

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SANBAR 20

Alloy Digest ◽

10.31399/asm.ad.sa0501 ◽

1999 ◽

Vol 48 (8) ◽

Keyword(s):

Wear Resistance ◽

Fatigue Strength ◽

Tensile Properties ◽

High Strength ◽

Heat Treating ◽

Steel Company ◽

High Fatigue ◽

Molybdenum Steel ◽

Rolled Condition

Abstract SANBAR 20 is a high-strength chromium-molybdenum steel with high-fatigue strength and excellent wear resistance in the as-rolled condition. The primary application is use as integral drill rods. This datasheet provides information on composition, hardness, and tensile properties. It also includes information on forming, heat treating, and machining. Filing Code: SA-501. Producer or source: Sandvik Steel Company.

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A new design of cable anchor for ultra-high fatigue stress cable net of largest telescope in the world

Thin-Walled Structures ◽

10.1016/j.tws.2020.107280 ◽

2020 ◽

pp. 107280

Author(s):

Wanxu Zhu ◽

Kefei Jia ◽

Feng Fu ◽

Dongqiu Lan ◽

Kai Qian

Keyword(s):

Fatigue Stress ◽

The World ◽

High Fatigue

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Psychological and Physiological Features Associated with Swimming Performance

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18094561 ◽

2021 ◽

Vol 18 (9) ◽

pp. 4561

Author(s):

Vicente Javier Clemente-Suárez ◽

Juan Pedro Fuentes-García ◽

Ricardo J. Fernandes ◽

João Paulo Vilas-Boas

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Swimming Performance ◽

Aerobic Performance ◽

Anaerobic Performance ◽

Probe Characteristic ◽

Time Domains ◽

High Fatigue ◽

Psychological Features ◽

Aerobic And Anaerobic

Background: The aim of the present research was to study the psychological and physiological features associated with aerobic and anaerobic performance in trained swimmers. Methods: A correlation and stepwise regression analyses were conducted with the data obtained in a RESTQ-76 sport questionnaire, a heart rate variability test, and an anaerobic and aerobic swimming performance efforts of 20 swimmers. Results: Aerobic performance correlated, principally, with parameters related to parasympathetic modulation measured in the frequency and time domains of the heart rate variability (LF/HF r: −0.806, p < 0.001; NN50 r: 0.937, p < 0.001). Swimmers’ anaerobic performance correlated to psychological features (low stress r: 0.526, p: 0.025, and high fatigue r: −0.506, p: 0.032). Conclusion: Swimming performance presented different psychological and physiological features depending on the probe characteristic. Specifically, swimmers’ anaerobic performance was associated with psychological features (low stress and high fatigue perception) and aerobic performance with physiological features (high parasympathetic modulation). This information could help coaches to know the variables to control in their swimmers, depending on the probe in which they compete (anaerobic or aerobic).

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Effect of mesoscale phase contrast on fatigue-delaying behavior of self-healing hydrogels

Science Advances ◽

10.1126/sciadv.abe8210 ◽

2021 ◽

Vol 7 (16) ◽

pp. eabe8210

Author(s):

Xueyu Li ◽

Kunpeng Cui ◽

Takayuki Kurokawa ◽

Ya Nan Ye ◽

Tao Lin Sun ◽

...

Keyword(s):

Crack Growth ◽

Fatigue Resistance ◽

Phase Contrast ◽

Stress Singularity ◽

Soft Materials ◽

Self Healing ◽

Strong Phase ◽

Mesoscale Structure ◽

High Fatigue ◽

Affine Deformation

We investigate the fatigue resistance of chemically cross-linked polyampholyte hydrogels with a hierarchical structure due to phase separation and find that the details of the structure, as characterized by SAXS, control the mechanisms of crack propagation. When gels exhibit a strong phase contrast and a low cross-linking level, the stress singularity around the crack tip is gradually eliminated with increasing fatigue cycles and this suppresses crack growth, beneficial for high fatigue resistance. On the contrary, the stress concentration persists in weakly phase-separated gels, resulting in low fatigue resistance. A material parameter, λtran, is identified, correlated to the onset of non-affine deformation of the mesophase structure in a hydrogel without crack, which governs the slow-to-fast transition in fatigue crack growth. The detailed role played by the mesoscale structure on fatigue resistance provides design principles for developing self-healing, tough, and fatigue-resistant soft materials.

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An Investigation of Mechanical Properties on Aluminium 6061 Reinforced with Silicon Carbide - Metal Matrix Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.787.568 ◽

2015 ◽

Vol 787 ◽

pp. 568-572 ◽

Cited By ~ 2

Author(s):

A. Radha ◽

K.R. Vijayakumar

Keyword(s):

Mechanical Properties ◽

Silicon Carbide ◽

Metal Matrix ◽

Charpy Impact ◽

Vortex Method ◽

Weight Fraction ◽

Stir Casting ◽

Matrix Composites ◽

Casting Technique ◽

High Fatigue

Composite materials like Aluminium metal matrix composite is playing a very important role in manufacturing industries e.g. automobile and aerospace industries, due to their superior properties such as light weight, low density, high specific modulus, high fatigue strength etc., In this study Aluminium(Al 6061) is reinforced with Silicon Carbide particles and fabricated by Stir Casting Technique (vortex method). The MMC rectangular bars (samples) are prepared with Al6061 and SiC (28 µ size) as the reinforced particles by weight fraction from 0%, 5%, 10%, and 15% of SiC. The microstructure analysis and Mechanical properties like Tensile Strength, Vickers Hardness and Charpy Impact Strength were investigated on prepared specimens. It is observed that the properties are increased with increasing of reinforced specimens by weight fraction.

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Flow Coefficient Evaluation of Poppet Valves Used in Reciprocating Compressors for LDPE

Volume 5: High Pressure Technology; Nondestructive Evaluation Division; Student Paper Competition ◽

10.1115/pvp2008-61286 ◽

2008 ◽

Author(s):

Enzo Giacomelli ◽

Massimo Schiavone ◽

Fabio Manfrone ◽

Andrea Raggi

Keyword(s):

Pressure Drop ◽

Time Pressure ◽

Experimental Tests ◽

Operating Conditions ◽

Flow Coefficient ◽

Operating Life ◽

High Fatigue ◽

Strongly Connected ◽

And Performance ◽

Poppet Valves

Poppet valves have been used for a long time for very high pressure reciprocating compressors, as for example in the case of Low Density Polyethylene. These applications are very critical because the final pressure can reach 350 MPa and the evaluation of the performance of the machines is strongly connected to the proper operation and performance of the valve itself. The arrangement of cylinders requires generally a certain compactness of valve to withstand high fatigue stresses, but at the same time pressure drop and operating life are very important. In recent years the reliability of the machines has been improving over and over and the customers’ needs are very stringent. Therefore the use of poppet valves has been extended to other cases. In general the mentioned applications are heavy duty services and the simulation of the valves require some coefficients to be used in the differential equations, able to describe the movement of plate/disk or poppet and the flow and related pressure drop through the valves. Such coefficients are often determined in an experimental way in order to have a simulation closer to the real operating conditions. For the flow coefficients it is also possible today to use theoretical programs capable of determining the needed values in a quick and economical way. Some investigations have been carried out to determine the values for certain geometries of poppet valves. The results of the theory have been compared with some experimental tests. The good agreement between the various methods indicates the most suitable procedure to be applied in order to have reliable data. The advantage is evident as the time necessary for the theoretical procedure is faster and less expensive. This is of significant importance at the time of the design and also in case of a need to provide timely technical support for the operating behavior of the valves. Particularly for LDPE, the optimization of all the parameters is strongly necessary. The fatigue stresses of cylinder heads and valve bodies have to match in fact with gas passage turbulence and pressure drop, added to the mechanical behavior of the poppet valve components.

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Influence of the Perception of Barriers in Practice of PA in Adolescents: Explanatory Model

Healthcare ◽

10.3390/healthcare9040380 ◽

2021 ◽

Vol 9 (4) ◽

pp. 380

Author(s):

Iago Portela-Pino ◽

Myriam Alvariñas-Villaverde ◽

Javier Martínez-Torres ◽

Margarita Pino-Juste

Keyword(s):

Physical Activity ◽

Body Image ◽

Risk Factor ◽

Social Anxiety ◽

Activity Index ◽

School Year ◽

Factorial Model ◽

High Fatigue ◽

Physical Activity Index ◽

And Gender

Background: Sedentarism is an important risk factor for non-communicable diseases. To avoid it, it is necessary to establish the barriers which influence a low level of practice of Physical Activity. Methods: This study, conducted with 833 students, aims to describe a model to explain the barriers determining the level of practice of Physical Activity in adolescents according to age, school year, BMI and gender. The inclusion of the analyzed barriers followed the tetra-factorial model: Body image/physical and social anxiety; Tiredness/laziness; Responsibilities/lack of time and Environment/facilities. Results: The barriers to Physical Activity in adolescents are fatigue and sloth, and temporary obligations. The barrier that least influences the practice of Physical Activity is the environment and body image. It is determined that the subjects with the lowest Physical Activity index were those with a high fatigue and laziness score and higher age. The level of physical activity of this population is medium (95% CI, 2.8274–2.9418). Conclusions: It is necessary to overcome tiredness or apathy towards the practice of Physical Activity, especially in those under 16 years of age.

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Ratcheting assessment of corroded elbow pipes subjected to internal pressure and cyclic bending moment

The Journal of Strain Analysis for Engineering Design ◽

10.1177/0309324721989897 ◽

2021 ◽

pp. 030932472198989

Author(s):

Ali Salehi ◽

Armin Rahmatfam ◽

Mohammad Zehsaz

Keyword(s):

Growth Rate ◽

Stainless Steel ◽

Internal Pressure ◽

Bending Moment ◽

Axial Direction ◽

Hoop Strain ◽

Cyclic Bending ◽

High Fatigue ◽

The Impact ◽

Cyclic Bending Moment

The present study aimed to study ratcheting strains of corroded stainless steel 304LN elbow pipes subjected to internal pressure and cyclic bending moment. To this aim, spherical and cubical shapes corrosion are applied at two depths of 1 mm and 2 mm in the critical points of elbow pipe such as symmetry sites at intrados, extrados, and crown positions. Then, a Duplex 2205 stainless steel elbow pipe is considered as an alternative to studying the impact of the pipe materials, due to its high corrosion resistance and strength, toughness, and most importantly, the high fatigue strength and other mechanical properties than stainless steel 304LN. In order to perform numerical analyzes, the hardening coefficients of the materials were calculated. The results highlight a significant relationship between the destructive effects of corrosion and the depth and shape of corrosion, so that as corrosion increases, the resulting destructive effects increases as well, also, the ratcheting strains in cubic corrosions have a higher growth rate than spherical corrosions. In addition, the growth rate of the ratcheting strains in the hoop direction is much higher across the studied sample than the axial direction. The highest growth rate of hoop strain was observed at crown and the highest growth rate of axial strains occurred at intrados position. Altogether, Duplex 2205 material has a better performance than SS 304LN.

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