Impact plume‐formed and protoplanetary disk high‐temperature components in CB and CH metal‐rich carbonaceous chondrites

2021 ◽  
Author(s):  
Alexander N. Krot ◽  
Michail I. Petaev ◽  
Kazuhide Nagashima ◽  
Elena Dobrică ◽  
Brandon C. Johnson ◽  
...  
Keyword(s):  
High Temperature ◽  
Protoplanetary Disk ◽  
Carbonaceous Chondrites ◽  
High Temperature Components

scholarly journals Rapid condensation of the first Solar System solids

2019 ◽  
Vol 116 (47) ◽  
pp. 23461-23466 ◽  
Author(s):  
Yves Marrocchi ◽  
Johan Villeneuve ◽  
Emmanuel Jacquet ◽  
Maxime Piralla ◽  
Marc Chaussidon
Keyword(s):  
High Temperature ◽  
Thermal Annealing ◽  
Large Mass ◽  
Protoplanetary Disk ◽  
Carbonaceous Chondrites ◽  
Si Isotopes ◽  
Si Isotope ◽  
Mass Dependent ◽  
Isotopic Measurements

Chondritic meteorites are composed of primitive components formed during the evolution of the Solar protoplanetary disk. The oldest of these components formed by condensation, yet little is known about their formation mechanism because of secondary heating processes that erased their primordial signature. Amoeboid Olivine Aggregates (AOAs) have never been melted and underwent minimal thermal annealing, implying they might have retained the conditions under which they condensed. We performed a multiisotope (O, Si, Mg) characterization of AOAs to constrain the conditions under which they condensed and the information they bear on the structure and evolution of the Solar protoplanetary disk. High-precision silicon isotopic measurements of 7 AOAs from weakly metamorphosed carbonaceous chondrites show large, mass-dependent, light Si isotope enrichments (–9‰ < δ30Si < –1‰). Based on physical modeling of condensation within the protoplanetary disk, we attribute these isotopic compositions to the rapid condensation of AOAs over timescales of days to weeks. The same AOAs show slightly positive δ25Mg that suggest that Mg isotopic homogenization occurred during thermal annealing without affecting Si isotopes. Such short condensation times for AOAs are inconsistent with disk transport timescales, indicating that AOAs, and likely other high-temperature condensates, formed during brief localized high-temperature events.

Assessing the Condition and Estimating the Remaining Lives of Pressure Components in a Methanol Plant Reformer: Part 1 — NDE

2016 ◽  
Author(s):  
Brian E. Shannon ◽  
Carl E. Jaske ◽  
Gustavo Miranda
Keyword(s):  
High Temperature ◽  
Creep Damage ◽  
Sensor Technology ◽  
Special Focus ◽  
Laser Measurements ◽  
Typical Data ◽  
Multiple Sensor ◽  
High Temperature Components ◽  
Inspection Techniques ◽  
Non Destructive

Statoil Tjelbergodden operates a 2,400 ton/day methanol plant in Norway. In order to assess the condition and reliability of high temperature components within the reformer, a series of advanced non-destructive examination (NDE) technologies were applied to radiant catalyst tubes, outlet pigtails, and outlet collection headers. The inspection techniques were selected and developed to provide data that could easily be used in the engineering assessment of the high-temperature components. Special focus was given to detecting and quantifying high-temperature creep damage. This paper describes the NDE techniques that were employed and provides examples of typical data obtained by using the techniques. Catalyst tubes were inspected using the H SCAN® (Figure 1) multiple sensor technology. This technique utilizes two types of ultrasonic sensors, eddy current sensors, laser measurements, and elevation location sensors in scanning each catalyst tube. The H SCAN® P-CAT™ (Figure 2) technique is applied to outlet pigtails, while the H SCAN® H-CAT™ (Figure 3) technique is applied to outlet headers.

Creative Design-by-Analysis Solutions Applied to High-Temperature Components

1993 ◽  
Vol 115 (3) ◽  
pp. 221-227
Author(s):  
A. K. Dhalla
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Detailed Analysis ◽  
Structural Response ◽  
Cost Effective ◽  
Element Analysis ◽  
Finite Element Software ◽  
Division 1 ◽  
High Temperature Components ◽  
Elevated Temperature Design

Elevated temperature design has evolved over the last two decades from design-by-formula philosophy of the ASME Boiler and Pressure Vessel Code, Sections I and VIII (Division 1), to the design-by-analysis philosophy of Section III, Code Case N-47. The benefits of design-by-analysis procedures, which were developed under a US-DOE-sponsored high-temperature structural design (HTSD) program, are illustrated in the paper through five design examples taken from two U.S. liquid metal reactor (LMR) plants. Emphasis in the paper is placed upon the use of a detailed, nonlinear finite element analysis method to understand the structural response and to suggest design optimization so as to comply with Code Case N-47 criteria. A detailed analysis is cost-effective, if selectively used, to qualify an LMR component for service when long-lead-time structural forgings, procured based upon simplified preliminary analysis, do not meet the design criteria, or the operational loads are increased after the components have been fabricated. In the future, the overall costs of a detailed analysis will be reduced even further with the availability of finite element software used on workstations or PCs.

Application of Damage Mechanics and Polynomial Chaos Expansion for Lifetime Prediction of High-Temperature Components Under Creep-Fatigue Loading

2020 ◽  
Author(s):  
Felix Koelzow ◽  
Muhammad Mohsin Khan ◽  
Christian Kontermann ◽  
Matthias Oechsner
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
Damage Mechanics ◽  
Fatigue Loading ◽  
Probabilistic Methods ◽  
Lifetime Prediction ◽  
Model Parameters ◽  
Creep Fatigue ◽  
High Temperature Components ◽  
Mechanics Concepts

Abstract Several (accumulative) lifetime models were developed to assess the lifetime consumption of high-temperature components of steam and gas turbine power plants during flexible operation modes. These accumulative methods have several drawbacks, e.g. that measured loading profiles cannot be used within accumulative lifetime methods without manual corrections, and cannot be combined directly to sophisticated probabilistic methods. Although these methods are widely accepted and used for years, the accumulative lifetime prediction procedures need improvement regarding the lifetime consumption of thermal power plants during flexible operation modes. Furthermore, previous investigations show that the main influencing factor from the materials perspective, the critical damage threshold, cannot be statistically estimated from typical creep-fatigue experiments due to massive experimental effort and a low amount of available data. This paper seeks to investigate simple damage mechanics concepts applied to high-temperature components under creep-fatigue loading to demonstrate that these methods can overcome some drawbacks and use improvement potentials of traditional accumulative lifetime methods. Furthermore, damage mechanics models do not provide any reliability information, and the assessment of the resultant lifetime prediction is nearly impossible. At this point, probabilistic methods are used to quantify the missing information concerning failure probabilities and sensitivities and thus, the combination of both provides rigorous information for engineering judgment. Nearly 50 low cycle fatigue experiments of a high chromium cast steel, including dwell times and service-type cycles, are used to investigate the model properties of a simple damage evolution equation using the strain equivalence hypothesis. Furthermore, different temperatures from 300 °C to 625 °C and different strain ranges from 0.35% to 2% were applied during the experiments. The determination of the specimen stiffness allows a quantification of the damage evolution during the experiment. The model parameters are determined by Nelder-Mead optimization procedure, and the dependencies of the model parameters concerning to different temperatures and strain ranges are investigated. In this paper, polynomial chaos expansion (PCE) is used for uncertainty propagation of the model uncertainties while using non-intrusive methods (regression techniques). In a further post-processing step, the computed PCE coefficients of the damage variable are used to determine the probability of failure as a function of cycles and evolution of the probability density function (pdf). Except for the selected damage mechanics model which is considered simple, the advantages of using damage mechanics concepts combined with sophisticated probabilistic methods are presented in this paper.

On Lifing Concepts for Cast High Temperature Components Based on LCF and Fracture Mechanics

Fatigue '96 ◽  
1996 ◽  
pp. 1165-1170
Author(s):  
P. Heuler ◽  
J.W. Bergmann ◽  
M. Vormwald
Keyword(s):  
High Temperature ◽  
Fracture Mechanics ◽  
High Temperature Components

Elevated-Temperature Life Assessment

2021 ◽  
pp. 146-166
Author(s):  
Arun Sreeranganathan ◽  
Douglas L. Marriott
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Stress Relaxation ◽  
Damage Mechanics ◽  
Elevated Temperatures ◽  
Constitutive Models ◽  
Life Assessment ◽  
Remaining Life ◽  
High Temperature Components ◽  
Remaining Life Assessment

Abstract This article provides some new developments in elevated-temperature and life assessments. It is aimed at providing an overview of the damage mechanisms of concern, with a focus on creep, and the methodologies for design and in-service assessment of components operating at elevated temperatures. The article describes the stages of the creep curve, discusses processes involved in the extrapolation of creep data, and summarizes notable creep constitutive models and continuum damage mechanics models. It demonstrates the effects of stress relaxation and redistribution on the remaining life and discusses the Monkman-Grant relationship and multiaxiality. The article further provides information on high-temperature metallurgical changes and high-temperature hydrogen attack and the steps involved in the remaining-life prediction of high-temperature components. It presents case studies on heater tube creep testing and remaining-life assessment, and pressure vessel time-dependent stress analysis showing the effect of stress relaxation at hot spots.

Analytical Approach to Selecting and Designing a Miniature Downhole Refrigerator

1992 ◽  
Vol 114 (4) ◽  
pp. 339-344 ◽  
Author(s):  
G. A. Bennett
Keyword(s):  
High Temperature ◽  
Failure Modes ◽  
Thermal Protection ◽  
Selection Process ◽  
Systematic Analysis ◽  
Design Changes ◽  
Protection Technology ◽  
High Temperature Components ◽  
Final Selection

The design approach and results from a series of analyses used to select a miniature high-temperature multi-watt refrigerator for thermally protecting downhole instruments are described. Thirty-one systems from nine physical or chemical processes were investigated and compared against the design criteria and constraints. Preliminary thermodynamic analyses and the results of a search for high-temperature components and refrigerants eliminated all but three processes and seven systems. These seven systems were re-evaluated based on a set of proposed design changes that reflect natural evolution from a prototype to commercial system application. Final selection considered refrigerator interactions with the geothermal logging system to define failure modes, ensure compatibility, and allow adaptability to changing conditions. The selected refrigerator design permits reliable, long-term active cooling of downhole instruments in hot wells. The consistent design, systematic analysis and unbiased selection process represent a new body of research results that provide potential for substantial advances in downhole thermal protection technology.

The potential of medium- and long-term life predictions for high-temperature components in power plants

1989 ◽  
Vol 39 (1-2) ◽  
pp. 57-72 ◽  
Author(s):  
The late Burkhard Neubauer ◽  
Felix Bietenbeck
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
High Temperature Components ◽  
Life Predictions

Interpretation of damage mechanics behaviour of two-bar structures for the life extension of high-temperature components

2003 ◽  
Vol 38 (2) ◽  
pp. 125-132 ◽  
Author(s):  
S-T Tu ◽  
X Ling
Keyword(s):  
High Temperature ◽  
Damage Mechanics ◽  
Creep Damage ◽  
Life Extension ◽  
Continuum Damage ◽  
Basic Model ◽  
Different Dimensions ◽  
Damage Theory ◽  
High Temperature Components

The creep damage behaviour of two-bar structures of different dimensions and materials is studied in terms of continuum damage theory. The basic model is used to interpret the effectiveness of life extension measures for complicated structures. It is found that replacement of the more damaged component prior to rupture will result in an optimized life extension efficiency, depending on the geometric or material difference between the damaged and less damaged components. This has potential to provide guidance on the effectiveness of life extension repairs in high-temperature plants.

Failure Mechanisms of High Temperature Components in Power Plants

2000 ◽  
Vol 122 (3) ◽  
pp. 246-255 ◽  
Author(s):  
R. Viswanathan ◽  
J. Stringer
Keyword(s):  
High Temperature ◽  
Power Plants ◽  
Failure Mechanisms ◽  
Laboratory Data ◽  
Broad Perspective ◽  
Section Size ◽  
Creep Fatigue ◽  
Ultimate Failure ◽  
High Temperature Components ◽  
Utility Deregulation

The principal mechanisms of failure of high temperature components include creep, fatigue, creep-fatigue, and thermal fatigue. In heavy section components, although cracks may initiate and grow by these mechanisms, ultimate failure may occur at low temperatures during startup-shutdown transients. Hence, fracture toughness is also a key consideration. Considerable advances have been made both with respect to crack initiation and crack growth by the above mechanisms. Applying laboratory data to predict component life has often been thwarted by inability to simulate actual stresses, strain cycles, section size effects, environmental effects, and long term degradation effects. This paper will provide a broad perspective on the failure mechanisms and life prediction methods and their significance in the context utility deregulation. [S0094-4289(00)00103-1]

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