Cyclic and Fatigue Behavior of the P355NL1 Steel Under Block Loading

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Hélder F. S. G. Pereira ◽  
Abílio M. P. De Jesus ◽  
Alfredo S. Ribeiro ◽  
António A. Fernandes
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
Cumulative Damage ◽  
Sequential Effects ◽  
Block Loading ◽  
Fatigue Damage Accumulation ◽  
Life Predictions

Current fatigue analyses of metallic structures undergoing variable amplitude loading, including pressure vessels, are mostly based on linear cumulative damage concepts, as proposed by Palmgren and Miner. This type of analysis neglects any sequential effects of the loading history. Several studies have shown that linear cumulative damage theories can produce inconsistent fatigue life predictions. In this paper, both fatigue damage accumulation and cyclic elastoplastic behaviors of the P355NL1 steel are characterized using block loading fatigue tests. The loading is composed of blocks of constant strain-controlled amplitudes, applied according to two and multiple alternate blocks sequences. Also, loading composed by blocks of variable strain-controlled amplitudes are investigated. The block loading illustrates that fatigue damage evolves nonlinearly with the number of load cycles, as a function of the block strain amplitudes. These observations suggest a nonlinear damage accumulation rule with load sequential effects for the P355NL1 steel. However, the damage accumulation nonlinearity and load sequential effects are more evident for the two block loading rather than for multiple alternate block sequences, which suggests that the linear Palmgren–Miner rule tends to produce better results for more irregular loading histories. Some phenomenological interpretations for the observed trends are discussed under a fracture mechanics framework.

Cyclic and Fatigue Behavior of the P355NL1 Steel Under Block Loading

2007 ◽  
Author(s):  
He´lder F. S. G. Pereira ◽  
Abi´lio M. P. De Jesus ◽  
Anto´nio A. Fernandes ◽  
Alfredo S. Ribeiro
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
Cumulative Damage ◽  
Sequential Effects ◽  
Block Loading ◽  
Fatigue Damage Accumulation ◽  
Life Predictions

Current fatigue analyses of metallic structures undergoing variable amplitude loading, including pressure vessels, are mostly based on linear cumulative damage concepts, as proposed by Palmgren and Miner. This type of analysis neglects any sequential effects of the loading history. Several studies have shown that linear cumulative damage theories can produce inconsistent fatigue life predictions. In this paper, both fatigue damage accumulation and cyclic elastoplastic behaviors of the P355NL1 steel are characterized, using block loading fatigue tests. The loading is composed by blocks of constant strain-controlled amplitudes, applied according to two and multiple alternate blocks sequences. Also, loading composed by blocks of variable strain-controlled amplitudes are investigated. The block loading illustrates that fatigue damage evolves nonlinearly with the number of load cycles, as a function of the block strain amplitudes. These observations suggest a nonlinear damage accumulation rule with load sequential effects for the P355NL1 steel. However, the damage accumulation nonlinearity and load sequential effects are more evident for the two block loading rather than for multiple alternate block sequences, which suggests that the linear Palmgren-Miner’s rule tend to produce better results for more irregular loading histories. Some phenomenological interpretations for the observed trends are discussed under a fracture mechanics framework.

Applying a Stepwise Load for Calculation of the S-N Curve for Trabecular Bone Based on the Linear Hypothesis for Fatigue Damage Accumulation

2012 ◽  
Vol 726 ◽  
pp. 39-42 ◽  
Author(s):  
Tomasz Topoliński ◽  
Artur Cichański ◽  
Adam Mazurkiewicz ◽  
Krzysztof Nowicki
Keyword(s):  
Trabecular Bone ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Applied Load ◽  
Fatigue Tests ◽  
Bone Sample ◽  
Linear Hypothesis ◽  
Fatigue Damage Accumulation

In this work were presented calculated fatigue curves based on fatigue tests of trabecular bone under stepwise load with the application of a linear hypothesis accumulation of fatigue damage. The investigation was performed on 61 cylindrical bone samples obtained from the neck of different femur heads. The bone sample fatigue tests were carried out under compression with stepwise increases of the applied load. The fatigue calculation assumed the Palmgren-Miner (P-M) linear hypothesis accumulation of fatigue damage and the associated modified formulae. The obtained mean fatigue curves were based on the modified stress σ/E0 (E0 – initial stiffnes) for the assumed rule-determined slope or y-intercept. The highest agreement with the literature was obtained for Σn/N=10.

Investigation Into Cumulative Damage Rules to Predict Fretting Fatigue Life of Ti-6Al-4V Under Two-Level Block Loading Condition1

2003 ◽  
Vol 125 (3) ◽  
pp. 315-323 ◽  
Author(s):  
O. Jin ◽  
H. Lee ◽  
S. Mall
Keyword(s):  
Stress Amplitude ◽  
Fatigue Behavior ◽  
Fretting Fatigue ◽  
Fatigue Tests ◽  
Cumulative Damage ◽  
Order Effects ◽  
Block Loading ◽  
Crack Growth Rates ◽  
Damage Rule ◽  
Repeated Block

The effects of variable amplitude loading on fretting fatigue behavior of titanium alloy, Ti-6Al-4V were examined. Fretting fatigue tests were carried out under constant stress amplitude and three different two-level block loading conditions: high-low (Hi-Lo), low-high (Lo-Hi), and repeated block of high and low stress amplitudes. The damage fractions and fretting fatigue lives were estimated by linear and non-linear cumulative damage rules. Damage curve analysis (DCA) and double linear damage rule (DLDR) were capable to account for the loading order effects in Hi-Lo and Lo-Hi loadings. In addition, the predictions by DCA and DLDR were better than that by linear damage rule (LDR). Besides its simplicity of implementation, LDR was also capable of estimating failure lives reasonably well. Repeated two-level block loading resulted in shorter lives and lower fretting fatigue limit compared to those under constant amplitude loading. The degree of reduction in fretting fatigue lives and fatigue strength depended on the ratio of cycles at lower stress amplitude to that at higher stress amplitude. Fracture surface of specimens subjected to Hi-Lo and repeated block loading showed the clear evidence of change in stress amplitude of applied load. Especially, the repeated two-level block loading resulted in characteristic markers which reflected change in crack growth rates corresponding to different stress amplitudes.

Cumulative fatigue damage assessment and life predictions of as-forged vs QT V-based MA steels using two-step loading experiments

2003 ◽  
Vol 217 (2) ◽  
pp. 145-155 ◽  
Author(s):  
L Yang ◽  
A Fatemi
Keyword(s):  
Fatigue Damage ◽  
Life Prediction ◽  
Damage Accumulation ◽  
Damage Models ◽  
Fatigue Damage Accumulation ◽  
Loading Tests ◽  
Cumulative Fatigue Damage ◽  
Life Predictions ◽  
Different Characteristics ◽  
Quenching And Tempering

This study examines the fatigue damage accumulation process associated with a commonly produced forged vanadium-based microalloyed (MA) steel and its comparison with its quenched and tempered (Q&T) counterpart at the same hardness level. The advantage of MA steels compared to the traditional Q&T steels is the elimination of the costly quenching and tempering processes. Completely reversed strain-controlled two-level block loading tests were conducted on smooth axial specimens at room temperature. Under multi-level block cycling, the two steels displayed different characteristics, though they showed similar behaviour in constant amplitude fatigue. Therefore, a key to successful assessment of fatigue damage accumulation under variable amplitude service loading is selection of an appropriate cumulative fatigue life prediction model which reflects the material's damage characteristics. The effectiveness of several cumulative fatigue damage models and their life prediction capabilities are evaluated using the experimental data.

Fatigue damage accumulation of cold expanded hole in aluminum alloys subjected to block loading

2005 ◽  
Vol 27 (10-12) ◽  
pp. 1347-1353 ◽  
Author(s):  
S GARCIA ◽  
A AMROUCHE ◽  
G MESMACQUE ◽  
X DECOOPMAN ◽  
C RUBIO
Keyword(s):  
Aluminum Alloys ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Block Loading ◽  
Fatigue Damage Accumulation

A Modified Cumulative Damage Model for Fatigue Life Prediction under Variable Amplitude Loadings

2016 ◽  
Vol 853 ◽  
pp. 62-66 ◽  
Author(s):  
Peng Yue ◽  
Qiang Lei ◽  
Cheng Lin Zhang ◽  
Shun Peng Zhu ◽  
Hong Zhong Huang
Keyword(s):  
Fatigue Damage ◽  
Life Prediction ◽  
Damage Accumulation ◽  
Damage Model ◽  
Cumulative Damage ◽  
Mean Stress ◽  
Stress Model ◽  
Proposed Model ◽  
Fatigue Damage Accumulation ◽  
Cumulative Damage Model

To evaluate the fatigue damage accumulation and predict the residual life of components at different stress levels, this paper proposed a modified cumulative damage model based on the strain energy density parameter. Noting that mean stress and load interaction under uniaxial fatigue loading exhibit significant effects on fatigue damage accumulation and life prediction. According to this, a new model based on damaged stress model which considers the effects of mean stress and load interaction was presented in this paper. The proposed model was verified by using four experimental data sets of aluminium alloys and steels. The experimental results are compared with those of the Miner’s rule, damaged stress model (DSM) and damaged energy model (DEM). Results show that the proposed model agrees better with the experimental observations than others.

Probabilistic Non-Linear Cumulative Fatigue Damage of the P355NL1 Pressure Vessel Steel

2016 ◽  
Author(s):  
José António Fonseca de Oliveira Correia ◽  
Abílio Jesus ◽  
Sergio Blasón ◽  
Miguel Calvente ◽  
Alfonso Fernández-Canteli
Keyword(s):  
Fatigue Damage ◽  
Pressure Vessel ◽  
Damage Accumulation ◽  
Probabilistic Approach ◽  
Synergetic Effect ◽  
Pressure Vessel Steel ◽  
Sequential Effects ◽  
Vessel Steel ◽  
Fatigue Damage Accumulation ◽  
Non Linear

Miner’s rule for fatigue damage accumulation does not address conveniently the sequential effects of the fatigue loading due to underloads or overloads though such effects need to be taken into account for specific applications using a convenient model. Non-conservative (unsafe) or over-conservative (non-economic) fatigue predictions may result from such a linear damage analysis. To overcome these limitations, non-linear damage approaches are being proposed in the literature, as for instance, the double linear damage rule (DLDR). Further, advanced probabilistic models, as an alternative to deterministic ones, are being currently applied to fatigue damage assessment under variable (random) amplitude loading, though without including, up to present, sequential effects on the damage accumulation. In this paper, the synergetic effect of applying a non-linear fatigue damage model based on the DLDR in conjunction with a probabilistic approach based on the p-S-N field is pursued allowing the above mentioned sequential effects to be incorporated into a probabilistic damage prediction. The proposed approach was tested with existing fatigue block loading data available for the P355NL1 pressure vessel steel.

Microscopic Analysis of Fatigue Damage Accumulation in TiAl Intermetallics

2014 ◽  
Author(s):  
Luca Patriarca ◽  
Can Içöz ◽  
Mauro Filippini ◽  
Stefano Beretta
Keyword(s):  
Fatigue Damage ◽  
Titanium Aluminide ◽  
Damage Accumulation ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Image Correlation ◽  
Gamma Titanium Aluminide ◽  
Full Field ◽  
Fatigue Damage Accumulation ◽  
Residual Strains

In order to design efficient and light components for the aircraft industry preserving the safety of the design, more sophisticated design criteria are required for the application of new materials. In particular, the usage of novel manufacturing processes to produce advanced materials such as the gamma titanium aluminide alloys (γ-TiAl) requires the investigation of the microstructure influence in the fatigue damage accumulation processes. In this work we examine a Ti-48Al-2Cr-2Nb alloy obtained with an additive manufacturing technique by Electron Beam Melting (EBM) by conducting monotonic and fatigue experiments both on tension and compression samples. The full-field residual strain maps corresponding to different applied stress levels and number of cycles are obtained through the use of high-resolution Digital Image Correlation (DIC). The strain maps were overlaid with the images of the microstructure and detailed analyses were performed to investigate the features of the microstructure where high local strain heterogeneities arise. High local residual plastic shear strains were measured inside lamellar colonies, which are detected as the precursor to fatigue crack initiation. The measure of the residual strains also provides further information on the role of the intermetallic phases on the fatigue behavior of γ-TiAl alloys.

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