Crack Growth Simulation Under Complicated Stress Field Using S-Version FEM

2016 ◽  
Author(s):  
Koichi Masaki ◽  
Kazuya Osakabe ◽  
Akiyuki Takahashi ◽  
Yoshitaka Wada ◽  
Masanori Kikuchi
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Crack Growth ◽  
Three Dimensional ◽  
Element Model ◽  
Welding Residual Stress ◽  
Stress Fields ◽  
Residual Stress Field ◽  
Element Mesh ◽  
Multiple Materials

In the S-version finite element method (S-FEM), a local detailed finite element mesh (local mesh) is superimposed on a coarse finite element model (global mesh) representing the global structure. In the S-FEM developed by Tokyo University of Science, the virtual crack closure integral method is employed to evaluate the stress intensity factor, and a local mesh is re-meshed automatically, which enables easy simulations of crack growth by users. Using S-FEM, crack growth can be simulated in both two- and three-dimensional stress fields, under thermal stress field, under welding residual stress field, and in multiple materials. This paper reports the latest results of the simulations of crack growth in the presence of complicated stress fields.

Stress Corrosion Cracking Analysis under Thermal Residual Stress Field Using S-FEM

2011 ◽  
Vol 462-463 ◽  
pp. 431-436 ◽  
Author(s):  
Masanori Kikuchi ◽  
Yoshitaka Wada ◽  
Yuto Shimizu ◽  
Yu Long Li
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Crack Growth ◽  
Fracture Behavior ◽  
Three Dimensional ◽  
Stress Fields ◽  
Crack Growth Behavior ◽  
Residual Stress Field ◽  
Energy Agency ◽  
Thermal Stress Field

Fracture in heat affected zone (HAZ) in welding has been a serious problem for the integrity of machines. Prediction of fracture behavior due to the residual stress field in HAZ is important. In this paper, S-Version FEM(S-FEM) is applied to simulate the crack growth under thermal and residual stress fields. For evaluation of stress intensity factor, virtual crack closure integral method (VCCM) is employed. In order to confirm the validity of this analysis, numerical results are compared with previously-reported analytical and experimental results. Then, crack growth analysis in piping structure with welding joint was conducted. The residual stress data was provided by JAEA, Japan Atomic Energy Agency, based on their numerical simulation. Using S-FEM, two- and three-dimensional analyses are conducted, and crack growth behavior under thermal stress field is studied and discussed.

Multipass low-plasticity burnishing induced residual stresses: Three-dimensional elastic-plastic finite element modelling

2004 ◽  
Vol 218 (6) ◽  
pp. 663-668 ◽  
Author(s):  
W Zhuang ◽  
B Wicks
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Moving Contact ◽  
Low Plasticity Burnishing

Low-plasticity burnishing (LPB) is a surface modification process involving complex cyclic plastic deformation that results in the development of a deep residual stress field. In order to achieve an optimal LPB-induced residual stress field for the geometry appropriate to the aircraft engine component, the key parameters of the LPB process, such as burnishing load, burnishing ball size and material properties, need to be determined. For this purpose, a three-dimensional non-linear moving contact finite element model is proposed to simulate the multipass LPB process and to predict the effects of those parameters on the resultant residual stress field. The material constitutive model used in the finite element analysis has been developed from the cyclic stress/strain response obtained from experimental measurements on the material. Prediction of the LPB-induced residual stresses by the finite element model appears to agree reasonably well with X-ray diffraction measurements.

A Fundamental Study of the Interaction of Residual Stress and Applied Loading on Fracture

2010 ◽  
Author(s):  
C. J. Aird ◽  
M. J. Pavier ◽  
D. J. Smith
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Crack Closure ◽  
Applied Load ◽  
Element Model ◽  
Residual Stress Field ◽  
Fundamental Study ◽  
Analytical Expression ◽  
Applied Loading

This paper presents the results of a fundamental finite-element based study of the crack-closure effects associated with combined residual and applied loading. First, an analytical expression for a representative two-dimensional residual stress field is derived. This residual stress field contains a central compressive region surrounded by an equilibrating tensile region. The analytical expression allows the size and shape of the field to be varied along with the magnitude of the residual stress. The residual stress field is then used as a prescribed initial stress field in a finite element model, in addition to a far field applied load. By introducing cracks of increasing length into these models, charts of stress-intensity-factor versus crack length are produced for different relative magnitudes of residual stress and applied load and for different sizes and shape of the residual stress field. These charts provide insight into the way in which crack-tip conditions evolve with crack growth under conditions of combined residual and applied loading and also enable conditions of crack closure and partial closure to be identified.

Temperature and Residual Stress Fields in an Austenitic Circumferential Pipe Weld

2002 ◽  
Author(s):  
Ruthard Bonn ◽  
Klaus Metzner ◽  
H. Kockelmann ◽  
E. Roos ◽  
L. Stumpfrock
Keyword(s):  
Residual Stress ◽  
Numerical Calculation ◽  
Stress Field ◽  
Quantitative Determination ◽  
Welding Residual Stress ◽  
Stress Fields ◽  
Residual Stress Field ◽  
Circumferential Welds ◽  
The Impact

The main target of a research programme “experimental and numerical analyses on the residual stress field in the area of circumferential welds in austenitic pipe welds”, sponsored by Technische Vereinigung der Großkraftwerksbetreiber e. V. (VGB) and carried out at MPA Stuttgart, was the validation of the numerical calculation for the quantitative determination of residual stress fields in austenitic circumferential pipe welds. In addition, the influence of operational stresses as well as the impact of the pressure test on the residual stress state had to be examined. By using the TIG orbital welding technique, circumferential welds (Material X 10 CrNiNb 18 9 (1.4550, corresponding to TP 347) were produced (geometric dimensions 255.4 mm I.D. × 8.8 mm wall) with welding boundary conditions and weld parameters (number of weld layers and weld built-up, seam volume, heat input) which are representative for pipings in power plants. Deformation and temperature measurements accompanying the welding, as well as the experimentally determined (X-ray diffraction) welding residual stress distribution, served as the basis for the verification of numeric temperature and residual stress field calculations. The material model on which the calculations were founded was developed by experimental weld simulations in the thermo-mechanical test rig GLEEBLE 2000 for the determination of the material behaviour at different temperatures and elasto-plastic deformation. The numeric calculations were carried out with the Finite Element program ABAQUS. The comparison of the calculation results with the experimental findings confirms the proven validation of the developed numerical calculation models for the quantitative determination of residual stresses in austenitic circumferential pipings. The investigation gives a well-founded insight into the complex thermo-mechanical processes during welding, not known to this extent from literature previously.

Numerical Study of Welding Sequence on the Residual Stress Field in a Thick-Walled Tee Joint

2011 ◽  
Vol 219-220 ◽  
pp. 1211-1214
Author(s):  
Wei Jiang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Factors Affecting ◽  
Welding Sequence ◽  
Welding Sequences ◽  
Three Dimensional Finite Element

Finite element simulation is an efficient method for studying factors affecting weld-induced residual stress distributions. In this paper, a validated three-dimensional finite element model consisting of sequentially coupled thermal and structural analyses was developed. Three possible symmetrical welding sequences, i.e. one-welder, two-welder and four-welder sequence, which were perceived to generate the least distortion in actual welding circumstances, were proposed and their influences on the residual stress fields in a thick-walled tee joint were investigated. Appropriate conclusions and recommendations regarding welding sequences are presented.

Thermal Simulation of an Arbitrary Residual Stress Field in a Fully or Partially Autofrettaged Thick-Walled Spherical Pressure Vessel

2008 ◽  
Author(s):  
M. Perl
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Field ◽  
Pressure Vessel ◽  
Stress Fields ◽  
Equivalent Temperature ◽  
Residual Stress Field ◽  
Element Analysis ◽  
Spherical Pressure ◽  
The Ideal

The equivalent thermal load was previously shown to be the only feasible method by which the residual stresses due to autofrettage and its redistribution, as a result of cracking, can be implemented in a finite element analysis, of a fully or partially autofrettaged thick-walled cylindrical pressure vessel. The present analysis involves developing a similar methodology for treating an autofrettaged thick-walled spherical pressure vessel. A general procedure for evaluating the equivalent temperature loading for simulating an arbitrary, analytical or numerical, spherosymmetric autofrettage residual stress field in a spherical pressure vessel is developed. Once presented, the algorithm is applied to two distinct cases. In the first case, an analytical expression for the equivalent thermal loading is obtained for the ideal autofrettage stress field in a spherical shell. In the second case, the algorithm is applied to the discrete numerical values of a realistic autofrettage residual stress field incorporating the Bauschinger effect. As a result, a discrete equivalent temperature field is obtained. Furthermore, a finite element analysis is performed for each of the above cases, applying the respective temperature field to the spherical vessel. The induced stress fields are evaluated for each case and then compared to the original stress. The finite element results prove that the proposed procedure yields equivalent temperature fields that in turn simulate very accurately the residual stress fields for both the ideal and the realistic autofrettage cases.

The Implementation of Inter-Element Model for Crack Growth Simulation

2004 ◽  
Vol 261-263 ◽  
pp. 687-692 ◽  
Author(s):  
Ahmad Kamal Ariffin ◽  
Syifaul Huzni ◽  
Nik Abdullah Nik Mohamed ◽  
Mohd Jailani Mohd Nor
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Propagation ◽  
Crack Growth ◽  
Crack Problem ◽  
Adaptive Mesh ◽  
Element Model ◽  
Error Norm ◽  
Element Analysis ◽  
Element Mesh

The implementation of inter-element model to simulate crack propagation by using finite element analysis with adaptive mesh is presented. An adaptive finite element mesh is applied to analyze two-dimension elastoplastic fracture during crack propagation. Displacement control approach and updated Lagrangean strategy are used to solve the non-linearity in geometry, material and boundary for plane stress crack problem. In the finite element analysis, remeshing process is based on stress error norm coupled with h-version mesh refinement to find an optimal mesh. The crack is modeled by splitting crack tip node and automatic remeshing calculated for each step of crack growth. Crack has been modeled to propagate through the inter-element in the mesh. The crack is free to propagates without predetermine path direction. Maximum principal normal stress criterion is used as the direction criteria. Several examples are presented to show the results of the implementation.

Three Dimensional Finite Element Analysis of a Split-Sleeve Cold Expansion Process

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
S. Ismonov ◽  
S. R. Daniewicz ◽  
J. C. Newman ◽  
M. R. Hill ◽  
M. R. Urban
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Expansion Process ◽  
Element Analysis ◽  
Cold Expansion ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A cold expansion process is used to prolong the fatigue life of a structure under cyclic loadings. The process produces a beneficial compressive residual stress zone in the hole vicinity, which retards the initiation and propagation of the crack at the hole edge. In this study, a three-dimensional finite element model of the split-sleeve cold expansion process was developed to predict the resulting residual stress field. A thin rectangular aluminum sheet with a centrally located hole was considered. A rigid mandrel and an elastic steel split sleeve were explicitly modeled with the appropriate contact elements at the interfaces between the mandrel, the sleeve, and the hole. Geometrical and material nonlinearities were included. The simulation results were compared with experimental measurements of the residual stress. The influence of friction and the prescribed boundary conditions for the sheet were studied. Differences between the split-sleeve- and the non-split-sleeve model solutions are discussed.

Fatigue Crack Propagation Simulation of Rubber Shock Absorbers

2011 ◽  
Vol 415-417 ◽  
pp. 2298-2303
Author(s):  
Jing Yu Zhai ◽  
Ying Yang ◽  
Qing Kai Han
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Crack ◽  
Crack Growth ◽  
Shock Absorber ◽  
Three Dimensional ◽  
Element Model ◽  
Initial Crack ◽  
Shock Absorbers ◽  
Element Method

Rubber shock absorbers are the key parts to isolate vibrations of the machinery and equipment. In this paper, a three dimensional finite element model of a rubber shock absorber is established; then the computation of three dimensional fatigue crack growth rates are discussed by using the nonlinear finite element method. The stress distribution which can determine the initial crack location and the possible risk surface under dynamic loads is obtained. The three dimensional crack growth is simulated by using finite element method and linear elastic fracture mechanics. A brittle fracture process of the rubber shock absorber along the dangerous surface is simulated by using the cohesive element of ABAQUS.

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