Modeling of Thermomechanical Processes in Energetic Equipment Elements Under In-Service Conditions and Estimation of their Operational Life with Accounting for a Material Degradation, Damages and Repair Procedures

2013 ◽  
Vol 9 (1) ◽  
pp. 21-32 ◽  
Author(s):  
B.D. Drobenko ◽  
Keyword(s):  
Material Degradation ◽  
Operational Life ◽  
Service Conditions ◽  
Thermomechanical Processes

Statistical modeling of drill pipes operational life-time under a regular loading

2020 ◽  
pp. 30-33
Author(s):  
V.I. Kucheryavy ◽  
◽  
A.M. Sharygin ◽  
V.L. Savich ◽  
S.N. Milkov ◽  
...  
Keyword(s):  
Statistical Modeling ◽  
Life Time ◽  
Operational Life ◽  
Drill Pipes

WIELAND-B18

Alloy Digest ◽  
2003 ◽  
Vol 52 (1) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Bend Strength ◽  
Service Conditions ◽  
Common Application

Abstract Wieland-B18 is a phosphor bronze with a composition that allows usage in slightly more severe service conditions than alloy B16 (UNS C52100). A common application is in slide bearings and slideways. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and bend strength as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: CU-696. Producer or source: Wieland Metals Inc., Wieland-Werke AG.

The Afterlife of a Tribunal

2018 ◽  
Author(s):  
Diane Orentlicher
Keyword(s):  
Extended Period ◽  
German Society ◽  
Norm Diffusion ◽  
Postwar Germany ◽  
The Past ◽  
Operational Life ◽  
Local Impact

The span of an international tribunal’s local impact is not the same as its operational life, as Germany’s evolved relationship with Nuremberg highlights. Recognizing that the ICTY’s impact in Bosnia and Serbia will continue to evolve after the Tribunal ends its work, this chapter considers the Tribunal’s future impact, focusing in particular on its potential to stimulate a future reckoning with Serbia’s wartime past. While recognizing myriad differences between post-Milošević Serbia and postwar Germany, this chapter explores factors behind the latter’s eventual emergence as a “model penitent” long after German society rejected the moral message the Allies hoped Nuremberg would impart. It suggests that, after an extended period of “transitional denial,” Nuremberg may have contributed to Germany’s far-reaching reckoning with the past through a process of delayed norm diffusion.

Fracture Toughness of Large Forgings for Power Producing Industry

2013 ◽  
Vol 577-578 ◽  
pp. 593-596 ◽  
Author(s):  
Václav Mentl
Keyword(s):  
Fracture Toughness ◽  
Chemical Composition ◽  
Steam Turbine ◽  
Mechanical Treatment ◽  
Material Degradation ◽  
The Real ◽  
Operational Safety ◽  
Local Properties ◽  
Thermo Mechanical Treatment ◽  
Shape And Size

The steam turbine rotors represent large components both in radial and axial directions. Their local properties generally differ from one forging to another, or if we compare head and bottom parts of the original ingot, or central and circumferential localities of one rotor body respectively, or if we compare the properties of separate discs e.g. in the case of welded rotors. These differences stem from both even slight changes in the chemical composition (of separate heats or even within one ingot) and thermo-mechanical treatment and in the differences in technology with respect to the real shape and size of the forgings in question. In the paper, the consequences of the differences in fracture toughness characteristics in various rotor localities are discussed with respect to the rotors operational safety taking into account the existence of cracks and material degradation.

scholarly journals Self-healing materials for space applications: overview of present development and major limitations

2021 ◽  
Author(s):  
Laura Pernigoni ◽  
Ugo Lafont ◽  
Antonio Mattia Grande
Keyword(s):  
Orbital Debris ◽  
Space Environment ◽  
Technological Evolution ◽  
Self Healing ◽  
Space Systems ◽  
Space Applications ◽  
Structural Fatigue ◽  
Operational Life ◽  
Technological Limitations ◽  
Human Exploration

AbstractIn the last decade, self-healing materials have become extremely appealing for the field of space applications, due to their technological evolution and the consequent possibility of designing space systems and structures able to repair autonomously after damage arising from impacts with micrometeoroids and orbital debris, from accidental contact with sharp objects, from structural fatigue or simply due to material aging. The integration of these novel materials in the design of spacecraft structures would result in increased reliability and safety leading to longer operational life and missions. Such concepts will bring a decisive boost enabling new mission scenario for the establishment of new orbital stations, settlement on the Moon and human exploration of Mars.The proposed review aims at presenting the newest and most promising self-healing materials and associated technologies for space application, along with the issues related to their current technological limitations in combination with the effect of the space environment. An introductory part about the outlooks and challenges of space exploration and the self-healing concept is followed by a brief description of the space environment and its possible effects on the performance of materials. Self-healing materials are then analysed in detail, moving from the general intrinsic and extrinsic categories down to the specific mechanisms.

scholarly journals Viscoelastic phase-field fracture using the framework of representative crack elements

2021 ◽  
Author(s):  
Bo Yin ◽  
Johannes Storm ◽  
Michael Kaliske
Keyword(s):  
Phase Field ◽  
Consistency Condition ◽  
Field Method ◽  
Anisotropic Elasticity ◽  
Phase Field Method ◽  
Internal Variables ◽  
Crack Model ◽  
Material Degradation ◽  
Discrete Crack ◽  
Deformation State

AbstractThe promising phase-field method has been intensively studied for crack approximation in brittle materials. The realistic representation of material degradation at a fully evolved crack is still one of the main challenges. Several energy split formulations have been postulated to describe the crack evolution physically. A recent approach based on the concept of representative crack elements (RCE) in Storm et al. (The concept of representative crack elements (RCE) for phase-field fracture: anisotropic elasticity and thermo-elasticity. Int J Numer Methods Eng 121:779–805, 2020) introduces a variational framework to derive the kinematically consistent material degradation. The realistic material degradation is further tested using the self-consistency condition, which is particularly compared to a discrete crack model. This work extends the brittle RCE phase-field modeling towards rate-dependent fracture evolution in a viscoelastic continuum. The novelty of this paper is taking internal variables due to viscoelasticity into account to determine the crack deformation state. Meanwhile, a transient extension from Storm et al. (The concept of representative crack elements (RCE) for phase-field fracture: anisotropic elasticity and thermo-elasticity. Int J Numer Methods Eng 121:779–805, 2020) is also considered. The model is derived thermodynamic-consistently and implemented into the FE framework. Several representative numerical examples are investigated, and consequently, the according findings and potential perspectives are discussed to close this paper.

scholarly journals Effect of in-service burnout effect on the transonic leakage flows over cavity tip model

2021 ◽  
pp. 095765092110121
Author(s):  
Zainab J Saleh ◽  
Eldad J Avital ◽  
Theodosios Korakianitis
Keyword(s):  
Turbine Blades ◽  
High Heat ◽  
Navier Stokes ◽  
Gas Temperature ◽  
Flow Measurements ◽  
Tip Leakage ◽  
Leakage Flows ◽  
Operational Life ◽  
Flow Interactions ◽  
Blade Tip

Increasing the gas temperature at the inlet to the high pressure turbine of gas turbine engines is known as a proven method to increase the efficiency of these engines. However, this will expose the blades’ surface to very high heat load and thermal damages. In the case of the un-shrouded turbine blades, the blade tip will be exposed to a significant thermal load due to the developed leakage flows in the tip gap, this leads to in-service burnout which degrades the blade tip and shortens its operational life. This paper studies the in-service burnout effect of the transonic tip flows over a cavity tip which is a configuration commonly used to reduce the tip leakage flows. This investigation is carried out experimentally within a transonic wind tunnel and computationally using steady and unsteady Reynolds Averaged Navier Stokes approaches. Various flow measurements are established and different flow behaviour including separation bubbles, shockwave development and distinct flow interactions are captured and discussed. It is found that when the tip is exposed to the in-service burnout, leakage flow behaves in a significantly different way. In addition, the effective tip gap becomes much larger and allows higher leakage mass flow rate in comparison to the sharp-edge tip (i.e. a tip at the beginning of its operational life). The tip leakage losses are found much higher for the round-edge cavity tip (i.e. a tip exposed to burn-out effect). Experimental and computational flow visualisations, surface pressure measurements and discharge coefficient variation are given and analysed for several pressure ratios across the tip gap.

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