Numerical Simulation of Temperature-Dependent, Anisotropic Tertiary Creep Damage

2009 ◽  
Author(s):  
Calvin Stewart ◽  
Ali Gordon ◽  
David Nicholson
Keyword(s):  
Numerical Simulation ◽  
Creep Damage ◽  
Tertiary Creep ◽  
Temperature Dependent

Numerical simulation of temperature dependent performance of InP-based tunnel junctions

2014 ◽  
Author(s):  
Chaffra A. Affouda ◽  
Matthew P. Lumb ◽  
Maria Gonzalez ◽  
Michael K. Yakes ◽  
Christopher G. Bailey ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Tunnel Junctions ◽  
Temperature Dependent

Development of a Single Walled Tank Under Cryogenic Conditions Made of Composite

2018 ◽  
Author(s):  
Philipp W. Kutz ◽  
Frank Otremba ◽  
Jan Werner ◽  
Christian Sklorz
Keyword(s):  
Numerical Simulation ◽  
Liquid Nitrogen ◽  
Test Stand ◽  
Insulation Material ◽  
Insulation Layer ◽  
Temperature Dependent ◽  
Plate Temperature ◽  
Glass Fiber Reinforced Plastic ◽  
Insulation Materials ◽  
Material Values

The use of glass-fiber reinforced plastic (GRP) can reduce the weight of tanks significantly. By replacing steel with GRP in tanks for gases (propane, etc.) a weight reduction of up to 50 % was reached. In this project not only the material should be optimized, but also the design. Previous tanks consist of a double-walled structure with an insulation layer between the two shells (e.g. vacuum). Goal of this project is to realize a single-walled construction of GRP with an insulation layer on the outside. To determine the temperature dependent material values, two different experiments are performed: In the first experiment, temperature dependent material properties of liquid nitrogen found in literature research are validated in a simple setup. The level of liquid nitrogen in a small jar is measured over the experiment time. Numerical simulation shows the change of nitrogen level with sufficient precision. In the second experiment, a liquid nitrogen is applied on one side of a GRP plate. Temperature is measured with thermocouples on top and bottom of the GRP plate, as well as in the middle of the plate. By use of numerical simulation, temperature dependent thermal conductivity is determined. In the third experiment, a test stand is designed to examine different insulation materials. In this test stand, the insulation material can easily be changed. A numerical simulation, in which the determined material data is used, is performed as well for this test stand. The experiments show, that GRP can be used in cryogenic environments. Multiphase simulations are a suitable tool to describe the energy absorption of thermal energy due to thermal phase change. Results on different insulation materials will follow.

Creep-Damage Analysis: Comparison Between Coupled and Uncoupled Models

2000 ◽  
Vol 122 (4) ◽  
pp. 408-412 ◽  
Author(s):  
S. Bhandari ◽  
X. Feral ◽  
J.-M. Bergheau ◽  
G. Mottet ◽  
P. Dupas ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Internal Pressure ◽  
Validation Study ◽  
Pressure Vessel ◽  
Creep Damage ◽  
Damage Analysis ◽  
Hypothetical Accident ◽  
Computer Codes ◽  
Damage Theory ◽  
Reactor Pressure

Numerical simulation of creep rupture of a reactor pressure vessel in a severe hypothetical accident needs to perfectly take account of interactions between creep phenomena and damage. The continuous damage theory enables to formulate models strongly coupling elasto-visco-plasticity and damage. Such models have been implemented in various computer codes and, in particular, in ASTER at Electricite´ de France, CASTEM 2000 at Commissariat a` l’Energie Atomique and SYSTUS+® at SYSTUS International. The objective of this paper is to present briefly a validation study of the three different numerical implementations and to compare the coupled approach to an uncoupled one on an example of a cylinder of the program “RUPTHER,” under internal pressure and heated to a temperature of 700°C. [S0094-9930(00)01004-0]

Overview of Proposed High Temperature Design Code Cases

2016 ◽  
Author(s):  
Peter Carter ◽  
T.-L. (Sam) Sham ◽  
Robert I. Jetter
Keyword(s):  
High Temperature ◽  
Yield Stress ◽  
Creep Damage ◽  
Cyclic Strain ◽  
Inelastic Strain ◽  
Cyclic Creep ◽  
Strain Accumulation ◽  
Temperature Dependent ◽  
Common Basis ◽  
Creep Fatigue

Proposals for high temperature design methods have been developed for primary loads, creep-fatigue and strain limits. The methodologies rely on a common basis and assumption, that elastic, perfectly plastic analysis based on appropriate properties reflects the ability of loads and stress to redistribute for steady and cyclic loading for high temperature as well as for conventional design. The cyclic load design analyses rely on a further key property, that a cyclic elastic-plastic solution provides an upper bound to displacements, strains and local damage rates. The primary load analysis ensures that the design load is in equilibrium with the code allowable stress, taking into account: i) The stress state dependent (multi-axial) rupture criterion, ii) The limit to stress re-distribution defined by the material creep law. The creep-fatigue analysis is focused on the cyclic creep damage calculation, and uses conventional fatigue and creep-fatigue damage calculations. It uses a temperature-dependent pseudo “yield” stress defined by the material yield and rupture data to identify cycles which will not cause creep damage > 1 for the selected life. Similarly the strain limits analysis bounds cyclic strain accumulation. It also uses a temperature-dependent pseudo “yield” stress defined by the material yield and creep strain accumulation data to identify cycles which will not cause average (membrane) inelastic strain > 1% for the design life. The paper gives an overview of the background and justification of these statements, and examples.

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