The Linear Matching Method and Its Software Tool for Creep Fatigue Damage Assessment

Author(s):  
Manu Puliyaneth ◽  
Graeme Jackson ◽  
Haofeng Chen ◽  
Yinghua Liu
Author(s):  
Manu Puliyaneth ◽  
Haofeng Chen

Abstract Creep-fatigue and creep-ratcheting life assessment of an SS304 weldolet considering full creep-cyclic plasticity interaction is investigated using the extended Direct Steady Cycle Analysis (eDSCA) within the Linear Matching Method Framework (LMMF). The creep behaviour is modelled using the Norton relationship, which is modified by the Arrhenius rule to account for the temperature variation within the weldolet. The introduction of a creep dwell increases the reverse plasticity resulting from the creep relaxation. This leads to both creep-fatigue and creep-ratcheting damage mechanisms at different regions within the weldment. For thermal load dominated loading combinations, creep ratcheting due to both cyclically enhanced creep and creep enhanced plasticity are observed based on the dwell period. The effect of dwell period, load and temperature on the creep-fatigue and creep-ratcheting interaction of a weldolet are presented. The simultaneous presence of various damage mechanisms at different locations within the weldment highlights the importance and requirement of the proposed creep-cyclic plasticity investigations at weld locations.


2016 ◽  
Vol 853 ◽  
pp. 366-371
Author(s):  
Daniele Barbera ◽  
Hao Feng Chen ◽  
Ying Hua Liu

As the energy demand increases the power industry has to enhance both efficiency and environmental sustainability of power plants by increasing the operating temperature. The accurate creep fatigue life assessment is important for the safe operation and design of current and future power plant stations. This paper proposes a practical creep fatigue life assessment case of study by the Linear Matching Method (LMM) framework. The LMM for extended Direct Steady Cycle Analysis (eDSCA) has been adopted to calculate the creep fatigue responses due to the cyclic loading under high temperature conditions. A pipe intersection with dissimilar material joint, subjected to high cycling temperature and constant pressure steam, is used as an example. The closed end condition is considered at both ends of main and branch pipes. The impact of the material mismatch, transitional thermal load, and creep dwell on the failure mechanism and location within the intersection is investigated. All the results demonstrate the capability of the method, and how a direct method is able to support engineers in the assessment and design of high temperature component in a complex loading scenario.


Author(s):  
Yevgen Gorash ◽  
Haofeng Chen

This paper presents parametric studies on creep-fatigue endurance of the steel AISI type 316N(L) weldments defined as types 1, 2 and 3 according to R5 Vol. 2/3 Procedure classification at 550°C. The study is implemented using the Linear Matching Method (LMM) and based upon previously developed creep-fatigue evaluation procedure considering time fraction rule. Several geometrical configurations of weldments with individual parameter sets, representing different fabrication cases, are developed. For each of configurations, the total number of cycles to failure N* in creep-fatigue conditions is assessed numerically for different loading cases. The obtained set of N* is extrapolated by the analytic function dependent on normalised bending moment M̃, dwell period Δt and geometrical parameters. Proposed function for N* shows good agreement with numerical results obtained by the LMM. Therefore, it is used for the identification of Fatigue Strength Reduction Factors (FSRFs) intended for design purposes and dependent on proposed variable parameters.


2010 ◽  
Vol 63 (2-3) ◽  
pp. 611-616 ◽  
Author(s):  
S. Joseph Winston ◽  
R. Srinivasan ◽  
P. Puthiya Vinayagam ◽  
P. Chellapandi ◽  
S. C. Chetal

2017 ◽  
Vol 40 (11) ◽  
pp. 1854-1867 ◽  
Author(s):  
D. Barbera ◽  
H. Chen ◽  
Y. Liu

1989 ◽  
pp. 1075-1082
Author(s):  
S.Z. Cheng ◽  
T. Asayama ◽  
Y. Tachibana ◽  
Y. Asada

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