scholarly journals Inelastic analysis procedure based on the Grade 91 unified viscoplastic constitutive model for ASME implementation

2019 ◽  
Author(s):  
M. C. Messner ◽  
T. -L. Sham
Keyword(s):  
Constitutive Model ◽  
Analysis Procedure ◽  
Inelastic Analysis ◽  
Grade 91

scholarly journals Calibration of Finn Model and UBCSAND Model for Simplified Liquefaction Analysis Procedures

2021 ◽  
Vol 11 (11) ◽  
pp. 5283
Author(s):  
Jui-Ching Chou ◽  
Hsueh-Tusng Yang ◽  
Der-Guey Lin
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Structural Damage ◽  
Simulation Analysis ◽  
Constitutive Models ◽  
Soil Liquefaction ◽  
Analysis Procedure ◽  
Liquefaction Resistance ◽  
Simplified Procedure ◽  
Liquefaction Analysis

Soil-liquefaction-related hazards can damage structures or lead to an extensive loss of life and property. Therefore, the stability and safety of structures against soil liquefaction are essential for evaluation in earthquake design. In practice, the simplified liquefaction analysis procedure associated with numerical simulation analysis is the most used approach for evaluating the behavior of structures or the effectiveness of mitigation plans. First, the occurrence of soil liquefaction is evaluated using the simplified procedure. If soil liquefaction occurs, the resulting structural damage or the following mitigation plan is evaluated using the numerical simulation analysis. Rational and comparable evaluation results between the simplified liquefaction analysis procedure and the numerical simulation analysis are achieved by ensuring that the liquefaction constitutive model used in the numerical simulation has a consistent liquefaction resistance with the simplified liquefaction analysis procedure. In this study, two frequently used liquefaction constitutive models (Finn model and UBCSAND model) were calibrated by fitting the liquefaction triggering curves of most used simplified liquefaction analysis procedures (NCEER, HBF, JRA96, and T-Y procedures) in Taiwan via FLAC program. In addition, the responses of two calibrated models were compared and discussed to provide guidelines for selecting an appropriate liquefaction constitutive model in future projects.

A Unified Constitutive Model With Optimized Parameters for Base and Diffusion Bonded Alloy 800H

2020 ◽  
Author(s):  
Heramb P. Mahajan ◽  
Tasnim Hassan
Keyword(s):  
Elevated Temperature ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Constitutive Model ◽  
Nuclear Power ◽  
Parameter Determination ◽  
Alloy 800H ◽  
Inelastic Analysis ◽  
Creep Fatigue ◽  
Plant Components

Abstract Current ASME Section III, Division 5 code provides elastic, simplified inelastic and inelastic analysis options for designing nuclear power plant components for elevated temperature service. These analyses methods may fail to capture the complex creep-fatigue response and damage accumulation in materials at elevated temperatures. Hence, for analysis and design of the nuclear power plant components at elevated temperature, a full inelastic analysis that can simulate creep-fatigue responses may be needed. Existing ASME code neither provides guidelines for using full inelastic analysis nor recommends the type of constitutive model to be used. Hence, a unified rate-dependent constitutive model incorporating a damage parameter will be developed, and its parameters for base metal will be determined. In addition, a full inelastic analysis methodology using this model to analyze the creep-fatigue performance of components for nuclear power applications will be developed. Base metal 800H (BM800H) data are collected from literature to determine constitutive material model parameters. The parameter determination methodology for a constitutive model is discussed. The optimized parameter set for BM 800H at different temperatures will be presented in the paper. Recommendations are provided on the constitutive model selection and its parameter determination techniques. In the future, this work will be continued for diffusion bonded Alloy 800H (DB800H) material, and obtained parameters will be compared.

A Unified Inelastic Constitutive Model for the Average Engineering Response of Grade 91 Steel

2018 ◽  
Author(s):  
M. C. Messner ◽  
V.-T. Phan ◽  
T.-L. Sham
Keyword(s):  
Mechanical Response ◽  
Kinematic Hardening ◽  
Cyclic Softening ◽  
Strain Rates ◽  
Rate Dependent ◽  
Inelastic Analysis ◽  
Different Temperatures ◽  
Grade 91 ◽  
Tension Compression Asymmetry ◽  
Grade 91 Steel

Grade 91 steel has been called out for use in advanced reactor intermediate heat exchangers and other components. The material has good high temperature creep resistance and thermal properties but has a complex microstructure that manifests as cyclic softening, work softening, and tension/compression asymmetry in its engineering mechanical response. We describe a unified viscoplastic model for the deformation of Grade 91 for an expected operating temperature range spanning from room temperature to approximately 650°C. The model transitions from a rate independent response at low temperatures and high strain rates to a rate dependent, unified viscoplastic response at high temperatures and low creep strain rates. The model captures work and cyclic softening in the material through combined isotropic-kinematic hardening and captures observed tension/compression asymmetry and related anomalous ratcheting effects through a non-J2 flow term. A particular focus of the model is on capturing the average response of Grade 91 as determined from a wide collection of experimental data at many different temperatures, rather than the response of a single set of experiments at a particular temperature. The final model is suitable for the engineering design of nuclear components via inelastic analysis using the ASME Section III, Division 5 procedures.

Dynamic elasto-plastic response of a reinforced concrete spandrel frame

1969 ◽  
Vol 59 (2) ◽  
pp. 855-864
Author(s):  
W. R. Walpole ◽  
R. Shepherd
Keyword(s):  
Reinforced Concrete ◽  
New Zealand ◽  
Digital Computer ◽  
Small Amplitude ◽  
Elastic Vibration ◽  
Analysis Procedure ◽  
Plastic Response ◽  
Inelastic Analysis ◽  
Beam Frame

abstract Following the construction of the sixteen story Jerningham Apartments building in Wellington, New Zealand, small amplitude shaking tests were conducted on the building and the development of an inelastic analysis procedure enabled the possible elastoplastic response of a portion of the reinforced concrete framework to be investigated using a digital computer. In this paper the correlation between the predicted and measured periods of elastic vibration is briefly referred to and the results of elastic and elasto-plastic analyses of the selected portion of the spandrel beam frame are presented.

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