Derivation of a Low-Cycle Fatigue Relationship Employing the J-Integral Approach to Crack Growth

2009 ◽  
pp. 33-33-14 ◽  
Author(s):  
DF Mowbray
Keyword(s):  
Crack Growth ◽  
Low Cycle Fatigue ◽  
Integral Approach ◽  
J Integral ◽  
Cycle Fatigue

A new cyclic J-integral for low-cycle fatigue crack growth

2006 ◽  
Vol 27 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Hong-jiu Hu ◽  
Xing-ming Guo ◽  
Pei-ning Li ◽  
Yu-jun Xie ◽  
Jie Li
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
J Integral ◽  
Cycle Fatigue

Relationship of Crack Growth Between Thermal-Mechanical and Isothermal Low-Cycle Fatigue at Elevated Temperatures

1987 ◽  
Vol 109 (2) ◽  
pp. 114-118 ◽  
Author(s):  
Masakazu Okazaki ◽  
Takashi Koizumi
Keyword(s):  
Growth Rate ◽  
Flow Stress ◽  
Crack Growth ◽  
Growth Rates ◽  
Elevated Temperatures ◽  
Low Cycle Fatigue ◽  
J Integral ◽  
Cycle Fatigue ◽  
The Difference ◽  
Crack Growth Rates

The surface and through crack growth behaviors of some steels in thermal-mechanical and isothermal low-cycle fatigue at elevated temperatures were investigated. It was shown that the crack growth rate under each test condition was successfully correlated with the cyclic J-integral range by the simple power law equation, regardless of crack configurations and test controlling modes. Based on the results thus obtained, the relationship between the crack growth rates of the two types of fatigue was discussed. When the crack growth rates in thermal-mechanical and isothermal low-cycle fatigue at elevated temperatures were correlated with the parameter of which the range of cyclic J-integral was divided by the equivalent flow stress defined in this work, they could be represented by a single curve approximately. The crack growth rates in isothermal fatigue under various test temperatures could be also represented by the same single crack growth curve described above, regardless of the test materials. From the above result, it was found that the difference of crack growth rate in both types of fatigue merely resulted from the difference of equivalent flow stress.

scholarly journals Low-Cycle Fatigue Crack Growth in Ti-6242 at Elevated Temperature

2014 ◽  
Vol 891-892 ◽  
pp. 422-427 ◽  
Author(s):  
Rebecka Brommesson ◽  
Magnus Hörnqvist ◽  
Magnus Ekh
Keyword(s):  
Crack Length ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Cycle Fatigue ◽  
Load Drop ◽  
Actual Measure ◽  
Smooth Bars ◽  
Number Of Cycles ◽  
The Relationship

During low-cycle fatigue test with smooth bars the number of cycles to initiation is commonly defined from a measured relative drop in aximum load. This criterion cannot be directly related to the actual measure of interest - the crack length. By relating data from controlled crack growth tests under low-cycle fatigue conditions of a high strength Titanium alloy at 350°C and numerical simulation of these tests, it is shown that it is possible to determine the relationship between load drop and crack length, provided that care is taken to consider all relevant aspects of the materials stress-strain response.

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.

Sign in / Sign up

Export Citation Format

Share Document