A Continued Evaluation of the Role of Material Hardening Behavior for the NeT TG1 and TG4 Specimens

2014 ◽  
Author(s):  
David J. Dewees ◽  
Phillip E. Prueter ◽  
Seetha Ramudu Kummari
Keyword(s):  
Structural Integrity ◽  
Plastic Material ◽  
Critical Factor ◽  
Material Model ◽  
Standard Test ◽  
Material Behavior ◽  
Weld Residual Stress ◽  
Hardening Models ◽  
Elastic Plastic Material

Modeling of cyclic elastic-plastic material behavior (hardening) has been widely identified as a critical factor in the finite element (FE) simulation of weld residual stresses. The European Network on Neutron Techniques Standardization for Structural Integrity (NeT) Project has provided in recent years both standard test cases for simulation and measurement, as well as comprehensive material characterization. This has allowed the role of hardening in simulation predictions to be isolated and critically evaluated as never before possible. The material testing information is reviewed, and isotropic, nonlinear kinematic and combined hardening models are formulated and tested. Particular emphasis is placed on material model selection for general fitness-for-service assessments, as it relates to the guidance for weld residual stress (WRS) in flaw assessments of in-service equipment in Annex E of the FFS standard, API 579-1/ASME FFS-1.

Structural Integrity Evaluation for the Analysis of Corroded Pipelines With Multiple Corrosion Defects

2006 ◽  
Author(s):  
Alejandro Andueza ◽  
Thiago Pontual
Keyword(s):  
Structural Integrity ◽  
Plastic Material ◽  
Material Model ◽  
Model Generation ◽  
The Finite Element Method ◽  
Failure Pressure ◽  
Linear Elastic ◽  
Asme Code ◽  
Corrosion Defects ◽  
Elastic Plastic Material

The structural integrity evaluation of corroded pipelines is very important for the management of systems that are in operation in order to help managers in the important decision of repairing the line. The required models for the analysis of corroded pipelines with multiple corrosion defects are in many cases a hard task to be generated. This paper presents a new methodology for the generation of full 3D hex meshes for the analysis using the Finite Element Method. The algorithm, developed specifically for the analysis of corroded pipelines, makes the task of model generation with multiple corrosion defects easier and faster. Examples with one and two corrosion defects are presented using a linear-elastic material model and the corresponding results compared to the criteria established by ASME code sec. VIII div. 2. The same models are analyzed using ideal elastic-plastic material model in order to determine the minimum failure pressure for the corroded pipes. The numerical failure pressures obtained are also compared to the values obtained from DNV RP-F101 method for single defects and experimental results. Finally, a new repairing methodology that allows the continuous operation of the pipeline in a safer way is presented. This methodology can help managers in the undertaking of scheduling a full repair of the pipeline in a much more flexible way.

Structural Integrity Research for Reactor Pressure Vessel Under In-Vessel Retention of a Core Melt

2016 ◽  
Author(s):  
Yongjian Gao ◽  
Yinbiao He ◽  
Ming Cao ◽  
Yuebing Li ◽  
Shiyi Bao ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Material Properties ◽  
Power Plants ◽  
Structural Integrity ◽  
Plastic Material ◽  
Plastic Region ◽  
Reactor Pressure Vessel ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Reactor Pressure

In-Vessel Retention (IVR) is one of the most important severe accident mitigation strategies of the third generation passive Nuclear Power Plants (NPP). It is intended to demonstrate that in the case of a core melt, the structural integrity of the Reactor Pressure Vessel (RPV) is assured such that there is no leakage of radioactive debris from the RPV. This paper studied the IVR issue using Finite Element Analyses (FEA). Firstly, the tension and creep testing for the SA-508 Gr.3 Cl.1 material in the temperature range of 25°C to 1000°C were performed. Secondly, a FEA model of the RPV lower head was built. Based on the assumption of ideally elastic-plastic material properties derived from the tension testing data, limit analyses were performed under both the thermal and the thermal plus pressure loading conditions where the load bearing capacity was investigated by tracking the propagation of plastic region as a function of pressure increment. Finally, the ideal elastic-plastic material properties incorporating the creep effect are developed from the 100hr isochronous stress-strain curves, limit analyses are carried out as the second step above. The allowable pressures at 0 hr and 100 hr are obtained. This research provides an alternative approach for the structural integrity evaluation for RPV under IVR condition.

Fatigue Evaluation in Mixing Zones: Comparison of Different Criteria of Fatigue

2008 ◽  
Author(s):  
J. M. Stephan ◽  
C. Gourdin ◽  
J. Angles ◽  
S. Quilici ◽  
L. Jeanfaivre
Keyword(s):  
Fatigue Damage ◽  
Thermal Stresses ◽  
Plastic Material ◽  
Material Behavior ◽  
Damage Evaluation ◽  
Elastic Plastic ◽  
Different Types ◽  
Elastic Plastic Material ◽  
Fatigue Evaluation

The distribution of unsteady temperatures in the wall of the 6" FATHER mixing tee mock-up is calculated for a loading configuration: The results seem realistic even if they are not still very accurate (see paper PVP2005-71592 [11]). On this basis, thermal stresses are evaluated for elastic and elastic-plastic material behavior. Then, different types of fatigue criteria are used to evaluate the fatigue damage. The paper develops a brief description of the criteria, the corresponding fatigue damage evaluation and attempts to explain the differences.

Experiment and Elastic-Plastic Modelling of the IPN160 Beam

2015 ◽  
Vol 769 ◽  
pp. 331-335
Author(s):  
Jakub Vasek ◽  
Oldrich Sucharda
Keyword(s):  
Computational Models ◽  
Plastic Material ◽  
Numerical Models ◽  
Steel Structure ◽  
Material Model ◽  
Nonlinear Material ◽  
Software Application ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Isoparametric Finite Elements

The paper compares the numerical models of and experiments with a beam. The purpose is to evaluate the nonlinear material model of a steel structure. The steel is modelled as an ideal elastic-plastic material. The FEM and eight-node isoparametric finite elements are considered in the analysis. The 3D calculations use different material constants and several approaches are being tested in order to create the computational models. The calculations are performed in the software application developed by our university.

Reducing Occupant Injury in Frontal Crashes for a Low-Floor City Bus

2005 ◽  
Author(s):  
Elham Sahraei Esfahani ◽  
Kurosh Darvish ◽  
Mohamad Parnianpour ◽  
Akbar Bateni
Keyword(s):  
Plastic Material ◽  
Material Model ◽  
Element Model ◽  
Driver Model ◽  
City Bus ◽  
Hybrid Iii ◽  
Occupant Injury ◽  
Occupant Injuries ◽  
Frontal Crashes ◽  
Elastic Plastic Material

In this research, the effect of beam buckling in a predefined direction is used to reduce occupant injuries in frontal crashes of an ultra-low-floor (ULF) city bus. In ULF buses, the floor structure consists of several longitudinal long beams, which in case of a frontal crash may buckle due to the axial impact. The direction of rotational acceleration of the driver seat due to buckling is highly affected by the position of the driver seat. A finite element model of an ULF bus was developed using LS-Dyna. The driver model, a Hybrid III 50th male dummy with deformable jacket and abdomen, was restrained to the seat with a 3-point belt. An Elastic-Plastic material model was used for the bus structure to investigate the buckling behavior of the beam elements. Using diagonal beams to guide the buckling in a desired direction, rewarding results were achieved in reducing the occupant injuries. For example, with an extra diagonal beam under the seat, the driver’s HIC15 was reduced from 739 to 415.7 and HIC36 from 791 to 700.6.

Study on Impinging Stream Flow Channel in Abrasive Flow Polishing Complex Cavity of Precision Mold

2013 ◽  
Vol 797 ◽  
pp. 469-474
Author(s):  
Di Feng Zhou ◽  
Dong Yu Liu
Keyword(s):  
Stream Flow ◽  
Plastic Material ◽  
Material Model ◽  
Impact Deformation ◽  
Element Simulation ◽  
Complex Cavity ◽  
Elastic Plastic Material ◽  
Set Up ◽  
The Impact ◽  
Abrasive Flow Polishing

In order to solve the problem about polishing complex cavity of precision mold, to improve the efficiency of processing and reduce the surface roughness, putting forward multiple entries impinging stream processing device.With making use of the collision of two strands of abrasive flow, Realizing the mutual disturbance of abrasive flow in the runner, and increasing the collision between abrasive to improve the disordering of abrasive movement, for promoting abrasive polishing to mold cavity. Johnson-Cook elastic-plastic material model is set up at the same time, using abaqus finite element simulation to simulate the impact deformation wear and cutting wear with the increasment of impact times.

Calibration of Elastic-Plastic Material Model for Tire Shreds

2004 ◽  
Author(s):  
Boris Jeremić ◽  
James Putnam ◽  
Kallol Sett ◽  
Dana Humphrey ◽  
Stacey Patenaude
Keyword(s):  
Plastic Material ◽  
Material Model ◽  
Elastic Plastic ◽  
Tire Shreds ◽  
Elastic Plastic Material
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