Validation of Inelastic Analysis by Full-Scale Component Testing

1987 ◽  
Vol 109 (1) ◽  
pp. 42-49 ◽  
Author(s):  
D. S. Griffin ◽  
A. K. Dhalla ◽  
W. S. Woodward
Keyword(s):  
Life Prediction ◽  
Elevated Temperatures ◽  
Full Scale ◽  
Prediction Methods ◽  
Material Models ◽  
Component Testing ◽  
Inelastic Analysis ◽  
Creep Buckling ◽  
Design Requirements ◽  
Thermal Striping

This paper compares theoretical and experimental results for full-scale, prototypical components tested at elevated-temperatures to provide validation for inelastic analysis methods, material models, and design limits. Results are discussed for piping elbow plastic and creep buckling, creep ratcheting, and creep relaxation; nozzle creep ratcheting and weld cracking; and thermal striping fatigue. Comparisons between theory and test confirm the adequacy of components to meet design requirements, but identify specific areas where life prediction methods could be made more precise.

Defective Pipeline Fatigue-Life Prediction Using Failure Assessment Diagram Technique

2004 ◽  
Author(s):  
Jinheng Luo ◽  
Xinwei Zhao ◽  
Qingren Xiong ◽  
Chunyong Huo
Keyword(s):  
Fatigue Life ◽  
Evaluation System ◽  
Life Prediction ◽  
Safety Evaluation ◽  
Load Ratio ◽  
Test System ◽  
Full Scale ◽  
Oil Pipeline ◽  
Failure Assessment Diagram ◽  
Failure Assessment

The life prediction, whose results can be used to define the inspection, repair or replacement cycle of in-service pipeline, is a main component of safety assessment of gas and oil pipeline. At present, failure Assessment Diagram (FAD) technique has been widely used in quantitative engineering safety evaluation system of pipeline that contains crack-like flaws. In past work, the authors developed a very useful model to predict the fatigue life of defective pipeline and established a computer calculating method. Based on FAD technique, toughness ratio and load ratio are calculated repeatedly with every crack increment in the model. With the self-developed full-scale test system, the full-scale pipe fatigue test was collected to verify the applicability of this method.

Non-Linear Stress Analysis of Complex Umbilical Cross-Sections

2002 ◽  
Author(s):  
Svein Sævik ◽  
Knut I. Ekeberg
Keyword(s):  
Cross Section ◽  
Axial Force ◽  
Plastic Material ◽  
Axial Strain ◽  
Development Program ◽  
Full Scale ◽  
Small Scale ◽  
Applied Theory ◽  
Element Formulation ◽  
Material Models

Nexans Norway is, together with Marintek, currently developing a software for detailed analysis of complex umbilical cross-section designs. The software development project combines numerical methods with small-scale testing of involved materials, as well as full-scale testing of a wide variety of umbilical designs, essential for calibration and verification purposes. Each umbilical design is modelled and comparisons are made with respect to global behaviour in terms of: • Axial strain versus axial force; • Axial strain versus torsion; • Torsion versus torsion moment for various axial force levels; • Moment versus curvature for different tension levels. The applied theory is based on curved beam and curved axisymmetric thin shell theories. The problem is formulated in terms of finite elements applying the Principle of Virtual Displacements. Each body of the cross-section interacts with the other bodies by contact elements which are formulated by a penalty formulation. The contact elements operate in the local surface coordinate system and include eccentricity, surface stiffness and friction effects. The software is designed to include the following functionality: • Arbitrary geometry modelling including helical elements wound into arbitrary order; • The helical elements may include both tubes and filled bodies; • Elastic, hyper-elastic, and elastic-plastic material models; • Initial strain; • Contact elements, including friction; • Tension, torsion, internal pressure, external pressure, bending and external contact loading (caterpillars, tensioners, etc.). The paper focuses on the motivation behind the development program including a description of the different activities. The theory is described in terms of kinematics, material models and finite element formulation. A test example is further presented comparing predicted behaviour with respect to full-scale test results.

scholarly journals Design of experiments for verification of computational life prediction methods

2019 ◽  
Vol 18 (3) ◽  
pp. 143-154
Author(s):  
O. V. Samsonova ◽  
K. V. Fetisov ◽  
I. V. Karpman ◽  
I. V. Burtseva
Keyword(s):  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Turbine Engines ◽  
Prediction Methods ◽  
Gas Turbine Engines ◽  
Loading Conditions ◽  
Load History ◽  
Strain Behavior ◽  
Before And After ◽  
Two Stages

The failure of heavily loaded rotating parts of aviation gas turbine engines may bring about dangerous consequences. The life of such parts is limited with the use of computational and experimental methods. Computational life prediction methods that are used without carrying out life-cycle tests of engine parts or assemblies should be substantiated experimentally. The best option for verifying the computational methods is to use the results of cyclic tests of model disks. These tests make it possible to reproduce loading conditions and surface conditions that correspond to those of real disks, and the data on the load history and material properties make it possible to simulate stress-strain behavior of disks under test conditions by calculation. This paper shows the process of planning such tests. It is assumed that the tests will be carried out in two stages - before and after the initiation of a low-cycle fatigue crack. A number of criteria are formulated that the geometry of model disks and their loading conditions are to satisfy. Based on these criteria, model disks were designed and the conditions for their testing were selected.

scholarly journals Benefits of sub-component over full-scale blade testing elaborated on a trailing edge bond line design validation

2017 ◽  
Author(s):  
Malo Rosemeier ◽  
Gregor Basters ◽  
Alexandros Antoniou
Keyword(s):  
Structural Reliability ◽  
Fatigue Testing ◽  
Bond Line ◽  
Full Scale ◽  
Testing Time ◽  
Trailing Edge ◽  
Pure Lead ◽  
Component Testing ◽  
Line Design ◽  
Full Scale Testing

Abstract. Wind turbine rotor blades are designed and certified according to the current IEC (2012) and DNV GL AS (2015) standards, which include the final full-scale experiment. The experiment is used to validate the assumptions made in the design models. In this work the drawbacks of traditional static and fatigue full-scale testing are elaborated, i. e. the replication of realistic loading and structural response. Sub-component testing is proposed as a potential method to mitigate some of the drawbacks. Compared to the actual loading that a rotor blade is subjected to under field conditions, the full-scale test loading is subjected to the following simplifications and constraints: First, the full-scale fatigue test is conducted as a cyclic test, where the load time series obtained from aero-servo-elastic simulations are simplified to a damage equivalent load range. Second, the load directions are typically applied solely in two directions, often pure lead-lag and flap-wise directions which are not necessarily the most critical load directions for a particular blade segment. Third, parts of the blade are overloaded by up to 20 % to achieve the target load along the whole span. Fourth, parts of the blade are not tested due to load introduction via load frames. Finally, another downside of a state-of-the-art, uni-axial, resonant, full-scale testing method is that dynamic testing at the eigenfrequencies of today's blades in respect of the first flap-wise mode between 0.4 Hz and 1.0 Hz results in long test times. Testing usually takes several months. In contrast, the sub-component fatigue testing time can be substantially faster than the full-scale blade test since (a) the load can be introduced with higher frequencies which are not constrained by the blade's eigenfrequency, and (b) the stress ratio between the minimum and the maximum stress exposure to which the structure is subjected can be increased to higher, more realistic values. Furthermore, sub-component testing could increase the structural reliability by focusing on the critical areas and replicating the design loads more accurately in the most critical directions. In this work, the comparison of the two testing methods is elaborated by way of example on a trailing edge bond line design.

A Viscoplastic Model for Alloy 617 for Use With the ASME Section III, Division 5 Design by Inelastic Analysis Rules

2021 ◽  
Author(s):  
M. C. Messner ◽  
T.-L. Sham
Keyword(s):  
High Temperature ◽  
Alloy 617 ◽  
Element Analysis ◽  
Material Models ◽  
Experimental Database ◽  
Viscoplastic Model ◽  
Analysis And Design ◽  
Inelastic Analysis ◽  
Wide Range ◽  
Creep Fatigue

Abstract The rules for the design of high temperature reactor components in Section III, Division 5, Subsection HB, Subpart B (HBB) of the ASME Boiler and Pressure Vessel Code contain two options for evaluating the deformation-controlled design limits on strain accumulation and creep-fatigue: design by elastic analysis and design by inelastic analysis. Of these options design by inelastic analysis tends to be less overconservative and produce more efficient designs. However, the HBB currently does not provide approved material models for use with the inelastic analysis rules, limiting their widespread use. A nonmandatory appendix has been developed to provide general guidance on appropriate material models and provide reference material models suitable for use with the design by inelastic analysis approach. This paper describes a viscoplastic model for Alloy 617 suitable for use with the HBB rules proposed for incorporation into the new appendix. The model represents the high temperature creep, creep-fatigue, and tensile response of Alloy 617 and accurately accounts for rate sensitivity across a wide range of temperatures. The focus in developing the model was on capturing key features of material deformation required for accurately executing the HBB rules and on developing a relatively simple model form that can be implemented in commercial finite element analysis software. The paper validates the model against an extensive experimental database collected as part of the Alloy 617 Code qualification effort as well as against specialized experimental tests examining the effect of elastic follow up on stress relaxation and creep deformation in the material.

Sign in / Sign up

Export Citation Format

Share Document