A prediction model for fatigue crack growth using effective cyclic plastic zone and low cycle fatigue properties

2016 ◽  
Vol 158 ◽  
pp. 209-219 ◽  
Author(s):  
K.K. Shi ◽  
L.X. Cai ◽  
S. Qi ◽  
C. Bao
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Plastic Zone ◽  
Prediction Model ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Cyclic Plastic ◽  
Cyclic Plastic Zone

Mode-II Fatigue Crack Growth Model from Shear-Type Low Cycle Fatigue Properties

2016 ◽  
Vol 853 ◽  
pp. 15-21
Author(s):  
Kai Kai Shi ◽  
Li Xun Cai ◽  
Shuang Qi ◽  
Chen Bao
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
Model Verification ◽  
Fatigue Properties ◽  
Mode Ii ◽  
Cycle Fatigue ◽  
Shear Type ◽  
Crack Growth Model

The inherent law between fatigue behaviors of shear-type representative volume element and mode-II fatigue crack growth is found in the range of cycle plastic zone near the crack tip. Prediction model for mode-II fatigue crack growth rate is then proposed by utilizing shear-type low cycle fatigue properties, plastic strain energy criterion, and effective cycle stress-strain field. Experimental data of two Aluminum alloys, 2024-T351 and 7075-T6, are used for the model verification. Good agreement between experimental and theoretical results is obtained.

Prediction of fatigue crack growth based on low cycle fatigue properties

2014 ◽  
Vol 61 ◽  
pp. 220-225 ◽  
Author(s):  
K.K. Shi ◽  
L.X. Cai ◽  
L. Chen ◽  
S.C. Wu ◽  
C. Bao
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue

A Model of Fatigue Crack Growth Based on Damage Accumulation

2004 ◽  
Author(s):  
Satish Chand ◽  
K. N. Pandey
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Plastic Zone ◽  
Crack Growth ◽  
Damage Accumulation ◽  
Process Zone ◽  
Crack Tip ◽  
Cyclic Plastic ◽  
Cyclic Plastic Zone ◽  
Material Element

A fatigue crack growth model based on cumulative damage is presented, when a material element ahead of the crack tip, is approached by the tip of the crack. The cyclic plastic zone and process zone ahead of the crack tip are taken as the area where damage accumulation takes place when the material element, first, enters into the cyclic plastic zone and then into the process zone. During this period, the Coffin-Manson damage law in conjunction with Miner’s linear damage accumulation is used to determine the damage in the material element. A constant strain gradient was assumed along the process zone ahead of the crack tip and the size of process zone was taken to be variable and dependent on the range of stress intensity factor. For a cyclic loading, the effective crack driving force takes into consideration the crack tip blunting process. The model results are in good agreement with experimental data available in literature for a number of materials.

Modeling of Fatigue Crack Growth under High-Low Sequence Loading

2012 ◽  
Vol 224 ◽  
pp. 65-68
Author(s):  
Zhi Wei Yao ◽  
Bao Xiang Qiu ◽  
Xiao Gui Wang
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Plastic Zone ◽  
Crack Growth ◽  
Crack Closure ◽  
Fatigue Crack Growth Rate ◽  
Cyclic Plastic ◽  
Cyclic Plastic Zone

The fatigue crack growth behavior of one compact tension specimen of 16MnR steel under high-low sequence loading was investigated. The symmetric half finite element model under plane-stress state was used to calculate the elastic-plastic stress-strain responses, in which the Armstrong-Frederick type cyclic plasticity model was implemented as a user material subroutine UMAT of ABAQUS. A recently developed dynamic crack growth model was used to simulate the effects of high loading step on the successive low loading step. The detailed evolution process of the crack closure and cyclic plastic zone within the retardation region of fatigue crack growth was obtained. The extend of the crack closure, the size of cyclic plastic zone and the stress gradient have significant influence on the fatigue crack growth rate. The predicted fatigue crack growth rate is in good agreement with the experimental data.

Reeled CRA Clad/Lined Pipeline Installation: Seastate Optimisation From Fatigue and Fracture Perspective

2018 ◽  
Author(s):  
Daowu Zhou ◽  
T. Sriskandarajah ◽  
Heidi Bowlby ◽  
Ove Skorpen
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
Superposition Method ◽  
Cycle Fatigue ◽  
Limit States ◽  
Simplified Approach ◽  
Fatigue And Fracture ◽  
Girth Welds

The deformation mechanism in reel-lay of corrosive resistance alloy (CRA) clad/lined pipes can facilitate defect tearing and low cycle fatigue crack growth in the girth welds. Pipe-lay after straightening will subject the CRA welds to high cycle fatigue. The permissible seastate for installation will be governed by failure limit states such as local collapse, wrinkling of the liner, fatigue and fracture. By means of a recently completed offshore project in North Sea, this paper discusses seastate optimisation when installing pipelines with CRA girth welds, from a fatigue and fracture perspective. The additional limiting requirement in CRA welds to maintain CRA liner integrity can lead to significant assessment work since all critical welds shall be examined. AUT scanned defect data were utilised to maximise permissible seastates based on fatigue allowance from a fatigue crack growth calculation. An alternative simplified approach to derive the crack growth based on a superposition method is studied. It enables a straightforward real-time prediction of crack growth and has the potential to be used during the offshore campaign to improve the installation flexibility. Post-installation fracture assessment under more critical seastates is examined for CRA partial over-matching welds. A comparison of CDF between conventional ECA procedure and 3D FE is provided.

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