Fatigue Modeling of a Notched Flat Plate Under Variable Amplitude Loading Supported by Elastoplastic Finite Element Method Analyses

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Hélder F. S. G. Pereira ◽  
Abílio M. P. De Jesus ◽  
Alfredo S. Ribeiro ◽  
António A. Fernandes
Keyword(s):  
Finite Element ◽  
Flat Plate ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Elastoplastic Analysis ◽  
Pressure Vessel Steel ◽  
Variable Amplitude Loading ◽  
Vessel Steel ◽  
Variable Amplitude ◽  
Amplitude Data

Although intensive research has been carried out to understand the fatigue behavior of steel notched components, under variable amplitude loading, no definite and general robust models have been derived so far. Therefore, every effort to augment the knowledge in this topic is welcomed. Within this context, existing variable amplitude data, derived by the authors for a notched low carbon pressure vessel steel (P355NL1) flat plate, is used to assess a local approach to fatigue. A linear damage summation framework, supported by elastoplastic finite element analyses, is used. Several variable amplitude loadings were selected and analyzed, using alternative configurations of kinematic hardening plasticity models (e.g., Chaboche’s model with distinct constants superposition). The predictions are assessed using available experimental data and data derived with simplified empirical elastoplastic tools. This paper highlights the difficulties of performing such elastoplastic analysis and compares the obtained results with those obtained using more classical tools for elastoplastic analysis (Glinka and Seeger–Heuler). It was found that fatigue predictions based on an elastoplastic finite element analysis, made using the Chaboche’s model, were significantly more accurate than predictions based on simplified elastoplastic analysis. These results have important practical relevance.

Fatigue Modelling of a Notched Geometry Under Variable Amplitude Loading Supported on Elastoplastic FEM Analyses

2010 ◽  
Author(s):  
He´lder F. S. G. Pereira ◽  
Abi´lio M. P. De Jesus ◽  
Alfredo S. Ribeiro ◽  
Anto´nio A. Fernandes
Keyword(s):  
Finite Element ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Elastoplastic Analysis ◽  
Pressure Vessel Steel ◽  
Low Carbon ◽  
Variable Amplitude Loading ◽  
Vessel Steel ◽  
Variable Amplitude ◽  
Amplitude Data

Despite intensive research has been carried out to understand the fatigue behavior of steel notched geometries, under variable amplitude loading, no definite and general robust models have been derived so far. Therefore, any effort to increment the knowledge in the topic is welcome. Within this premise, it is proposed an assessment of existing variable amplitude data, which has been derived by authors for a notched geometry, made from a low carbon pressure vessel steel (P355NL1), within the local approaches and linear damage summation framework, and supported by elastoplastic finite element analyses. Several variable amplitude loading are selected and analyzed using alternative configurations of kinematic hardening plasticity models (e.g. Chaboche’s model with distinct constants superposition). The predictions are assessed using available experimental data as well as with predictions made with simplified empiric elastoplastic tools. This paper highlights the difficulties on performing such elastoplastic analysis and compares the obtained results with those obtained using more classical tools for elastoplastic analysis. Fatigue predictions based on elastoplastic analysis made using the Chaboche’s model, with a finite element model, were significantly more accurate than predictions based on simplified elastoplastic analysis. The proposed information has important practical relevance.

Fatigue Life Prediction of Impacted Glass/Epoxy Composites under Variable Amplitude Loading

2004 ◽  
Vol 261-263 ◽  
pp. 1079-1084 ◽  
Author(s):  
Ki Weon Kang ◽  
Jong Kweon Kim
Keyword(s):  
Fatigue Life ◽  
Impact Damage ◽  
Fatigue Behavior ◽  
Equivalent Stress ◽  
Epoxy Composites ◽  
Constant Amplitude ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Amplitude Data ◽  
The Impact

This paper presents the fatigue behavior of plain-weave E-glass/epoxy composites with impact-induced damage under constant and variable amplitude loading. The constant amplitude fatigue life of the impacted composites can be identified through the prediction model, which was proposed on the carbon/epoxy laminates by authors. Also, the models are derived to calculate the equivalent stress of the composites under variable amplitude loading, considering the impact damage. These models allow fatigue data of the unimpacted and impacted composites under variable amplitude loading to be correlated with constant amplitude data of the unimpacted composites.

Dynamic Crack Propagation and Arrest in PWR Pressure Vessel Steel: Interpretation of Experiment With the X-FEM Method

2007 ◽  
Author(s):  
B. Prabel ◽  
S. Marie ◽  
A. Combescure
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Strain Rate ◽  
Thermal Shock ◽  
Crack Growth ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Crack Propagation ◽  
Dynamic Crack ◽  
Pressure Vessel Steel ◽  
Vessel Steel

In the frame of analysis of the pressure thermal shock in a PWR RVP and the associated R&D activities, some developments are performed at CEA on the dynamic brittle propagation and crack arrest. This paper presents a PhD work on the modeling of the dynamic brittle crack growth. For the analyses, an important experimental work is performed on different geometries using a French RPV ferritic steel: Compact Tension specimens with different thickness, isothermal rings under compression with different positions of the initial defect to study a mixed mode configuration, and a ring submitted to thermal shock. The first part of this paper details the test conditions and main results. To propose an accurate interpretation of the crack growth, a viscous-elastic-plastic dynamic model is used. The strain rate influence is taken into account based on Cowper-Symond’s law (characterization was made from Split Hopkinson Pressure Bar tests). To model the crack propagation in the Finite Element calculation, eXtended Finite Element Method (X-FEM) is used. The implementation of these specific elements in the CEA F.E. software CAST3M is described in the second part of this paper. This numerical technique avoids re-meshing, because the crack progress is directly incorporated in the degrees of freedom of the elements crossed by the crack. The last part of this paper compares the F.E. predictions to the experimental measurements using different criteria. In particular, we focused on a RKR (Ritchie-Knott-Rice) like criterion using a critical principal stress in the front of the crack tip during the dynamic crack extension. Critical stress is found to depend on crack speed, or equivalently on strain rate. Good results are reported concerning predictive simulations.

Probabilistic Fatigue Assessment of a Notched Detail Taking Into Account Mean Stress Effects

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Abílio M. P. De Jesus ◽  
M. Luisa Ruiz Ripoll ◽  
Alfonso Fernández-Canteli ◽  
Enrique Castillo ◽  
Hélder F. S. G. Pereira
Keyword(s):  
Probabilistic Model ◽  
Fatigue Behavior ◽  
Material Behavior ◽  
Test Series ◽  
Model Parameters ◽  
Pressure Vessel Steel ◽  
Mean Stress ◽  
Vessel Steel ◽  
Life Data ◽  
R Ratio

Probabilistic fatigue models are required to account conveniently for the several sources of uncertainty arising in the prediction procedures, such as the scatter in material behavior. In this paper, a recently proposed stress-based probabilistic model is assessed using fatigue data available for the P355NL1 steel (a pressure vessel steel). The referred probabilistic model is a log-Gumbel regression model, able to predict the probabilistic Wöhler field (P–S–N field), taking into account the mean stress (or stress R-ratio) effects. The parameters of the probabilistic model are identified using stress-life data derived for the P355NL1 steel, from smooth specimens, for three distinct stress R-ratios, namely R = −1, R = −0.5, and R = 0. The model requires a minimum of two test series with distinct stress R-ratios. Since data from three test series is available, extrapolations are performed to test the adequacy of the model to make extrapolations for stress R-ratios other than those used in the model parameters assessment. Finally, the probabilistic model is used to model the fatigue behavior of a notched plate made of P355NL1 steel. In particular, the P–S–N field of the plate is modeled and compared with available experimental data. Cyclic elastoplastic analysis of the plate is performed since plasticity at the notch root is developed. The probabilistic model correlated appropriately the stress-life data available for the P355NL1 steel and was able to perform extrapolations for stress ratios other than those used in the model identification. The P–S–N field identified using data from smooth specimens led to consistent predictions of the P–S–N field for a notched plate, demonstrating the adequacy of the probabilistic model also to predict the probabilistic Wöhler field for notched components.

The fatigue behavior of irradiated Reactor Pressure Vessel steel

2017 ◽  
Vol 82 ◽  
pp. 840-847 ◽  
Author(s):  
W. Zhong ◽  
Z. Tong ◽  
G. Ning ◽  
C. Zhang ◽  
H. Lin ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Fatigue Behavior ◽  
Reactor Pressure Vessel ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Reactor Pressure Vessel Steel ◽  
Reactor Pressure

Fatigue Behavior of AM60B Subjected to Variable Amplitude Loading

2012 ◽  
pp. 169-178
Author(s):  
H. Kang ◽  
K. Kari ◽  
A.K. Khosrovaneh ◽  
R. Nayaki ◽  
X. Su ◽  
...  
Keyword(s):  
Fatigue Behavior ◽  
Variable Amplitude Loading ◽  
Variable Amplitude
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