Thermal-Mechanical Fatigue Behavior of P92 T-Piece Pipe

2016 ◽  
Vol 853 ◽  
pp. 256-261
Author(s):  
Wei Zhang ◽  
Xiao Wei Wang ◽  
Jian Ming Gong ◽  
Yong Jiang ◽  
Xin Huang
Keyword(s):  
Plastic Strain ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Branch Pipe ◽  
Equivalent Plastic Strain ◽  
Cyclic Plasticity ◽  
Horizontal Pipe ◽  
Thermal Mechanical Fatigue ◽  
Mechanical Fatigue

This paper presents a study on thermal-mechanical fatigue (TMF) behavior of P92 T-piece pipe at the most critical working fluctuations. Pressure and temperature in out-of-phase (OP) and in-phase (IP) conditions were both taken into account. Cyclic plasticity model considering the effect of temperature were used, in which both effects of kinematic hardening and isotropic hardening were included. All of the parameters used in the simulation were obtained from high temperature low cycle fatigue tests (HTLCF). These parameters have been validated through the comparison of experiment data with the simulated data. Then, in order to investigate the effect of OP and IP loadings, thermal-mechanical fatigue finite element model (FEM) of P92 T-piece pipe was also developed. Simulated results reveal that at the most critical working fluctuations, the most dangerous position occurs at the region where the inner surface of horizontal pipe and branch pipe crossed for both IP and OP loadings. With the cycle increases, the equivalent plastic strain is increasing. The peak hoop stress and equivalent plastic strain at IP loading are higher than OP which indicates that IP loadings are more dangerous than OP loadings.

Modelling of Fretting Wear under Partial Slip Conditions Using Combined Isotropic-Kinematic Hardening Plasticity Model

2014 ◽  
Vol 1025-1026 ◽  
pp. 50-55
Author(s):  
Abdul Latif Mohd Tobi ◽  
M.Y. Ali ◽  
M.H. Zainulabidin ◽  
A.A. Saad
Keyword(s):  
Plastic Strain ◽  
Kinematic Hardening ◽  
Equivalent Plastic Strain ◽  
Fretting Wear ◽  
Cyclic Plasticity ◽  
Partial Slip ◽  
Plasticity Model ◽  
Slip Conditions ◽  
Contact Configuration ◽  
Specific Number

This paper presents finite element modelling of fretting wear under partial slip conditions using combined isotropic-kinematic hardening plasticity model with the emphasized to investigate the cyclic-plasticity behaviour predicted under fretting condition. The model is based on two-dimensional (2D) cylinder-on-flat contact configuration of titanium alloy, Ti-6Al-4V. A number of wear profiles at specific number of wear cycle (6000th, 60000th, 150000th and 300000th) are simulated. Contact pressure, tangential stress, shear stress, equivalent plastic strain, tangential plastic strain and also shear plastic strain are gathered and analysed. It is found that the plastic strain response of the combined isotropic-kinematic hardening plasticity model is slightly higher compare to linear kinematic hardening plasticity model [1].

Thermo-Mechanical Fatigue Behavior Investigation and Fracture Analysis on Austenitic Stainless Steel of Surge Line in Nuclear Power Plant

2010 ◽  
Vol 118-120 ◽  
pp. 166-170 ◽  
Author(s):  
Fei Xue ◽  
Zhi Feng Luo ◽  
Wei Wei Yu ◽  
Yan Liu ◽  
Xiao Chen ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Mechanical Strain ◽  
Fracture Analysis ◽  
Control Mode ◽  
Pressurized Water ◽  
Mechanical Fatigue ◽  
Significant Difference ◽  
Surge Line

In order to confirm the structural integrity of pressurizer surge line affected by thermal stratification and thermal shock, the thermo-mechanical fatigue (TMF) behavior of the material used for surge line was investigated based on the real situation in the pressurized water reactor (PWR). Smooth, hollow specimens were subjected to in-phase (IP) and out-of-phase (OP) cycling in air under a mechanical strain control mode. For the sake of comparison, low cycle fatigue (LCF) tests were also performed at the peak temperatures of TMF cycling. The Nano Hardness Tester was used to test the nano hardness of the sample on the cut section surface. The results are shown that there is no significant difference between the IP, OP and IF lives in the investigated temperature ranges. The fracture analysis reveals that the crack initiation and propagation occurred in a transgranular mode under OP, IP and IF cycling condition, and a harden layer occurrence may be the cause of the crack initiation.

The Effect of Nitrogen Alloying on the Low Cycle Fatigue and Creep-Fatigue Interaction Behavior of 316LN Stainless Steel

2013 ◽  
Vol 794 ◽  
pp. 441-448 ◽  
Author(s):  
G.V. Prasad Reddy ◽  
R. Sandhya ◽  
M.D. Mathew ◽  
S. Sankaran
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Hold Time ◽  
Cyclic Plasticity ◽  
Dynamic Strain ◽  
Cycle Fatigue ◽  
Intergranular Cracking ◽  
Creep Fatigue

Low cycle fatigue (LCF) and Creep-fatigue interaction (CFI) behavior of 316LN austenitic stainless steel alloyed with 0.07, 0.11, 0.14, .22 wt.% nitrogen is briefly discussed in this paper. The strain-life fatigue behavior of these steels is found to be dictated by not only cyclic plasticity but also by dynamic strain aging (DSA) and secondary cyclic hardening (SCH). The influence of the above phenomenon on cyclic stress response and fatigue life is evaluated in the present study. The above mentioned steels exhibited both single-and dual-slope strain-life fatigue behavior depending on the test temperatures. Concomitant dislocation substructural evolution has revealed transition in substructures from planar to cell structures justifying the change in slope. The beneficial effect of nitrogen on LCF life is observed to be maximum for 316LN with nitrogen in the range 0.11 - 0.14 wt.%, for the tests conducted over a range of temperatures (773-873 K) and at ±0.4 and 0.6 % strain amplitudes at a strain rate of 3*10-3 s-1. A decrease in the applied strain rate from 3*10-3 s-1 to 3*10-5 s-1 or increase in the test temperature from 773 to 873 K led to a peak in the LCF life at a nitrogen content of 0.07 wt.%. Similar results are obtained in CFI tests conducted with tensile hold periods of 13 and 30 minutes. Fractography studies of low strain rate and hold time tested specimens revealed extensive intergranular cracking.

High-Temperature Low-Cycle Fatigue Behavior of MarBN at 600 °C

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Richard A. Barrett ◽  
Eimear M. O'Hara ◽  
Padraic E. O'Donoghue ◽  
Sean B. Leen
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Material Model ◽  
Cyclic Softening ◽  
Cyclic Strength ◽  
Cycle Fatigue ◽  
Viscoplastic Material

This paper presents the high-temperature low-cycle fatigue (HTLCF) behavior of a precipitate strengthened 9Cr martensitic steel, MarBN, designed to provide enhanced creep strength and precipitate stability at high temperature. The strain-controlled test program addresses the cyclic effects of strain-rate and strain-range at 600 °C, as well as tensile stress-relaxation response. A recently developed unified cyclic viscoplastic material model is implemented to characterize the complex cyclic and relaxation plasticity response, including cyclic softening and kinematic hardening effects. The measured response is compared to that of P91 steel, a current power plant material, and shows enhanced cyclic strength relative to P91.

Thermal-mechanical fatigue behavior and lifetime prediction of P92 steel with different phase angles

2018 ◽  
Vol 109 ◽  
pp. 126-136 ◽  
Author(s):  
Xiang-Ming Pan ◽  
Xin Li ◽  
Le Chang ◽  
Guo-Dong Zhang ◽  
Fei Xue ◽  
...  
Keyword(s):  
Fatigue Behavior ◽  
Lifetime Prediction ◽  
P92 Steel ◽  
Thermal Mechanical Fatigue ◽  
Mechanical Fatigue ◽  
Phase Angles

Life Assessment of a Coke Drum by Using the Thermal-Mechanical Fatigue Properties and Laser Scanning Approach

2020 ◽  
Author(s):  
Zhiyuan Han ◽  
Guoshan Xie ◽  
Zengchao Wang ◽  
Jianzhong Yin ◽  
Jin Shi
Keyword(s):  
Fatigue Life ◽  
Laser Scanning ◽  
Low Cycle Fatigue ◽  
Complex Loading ◽  
Operating Conditions ◽  
Life Assessment ◽  
Fatigue Properties ◽  
Element Analysis ◽  
Thermal Mechanical Fatigue ◽  
Mechanical Fatigue

Abstract Coke drums are critical equipments in delayed coking plants, which are operated under severe thermal-mechanical conditions by cyclic heating and quenching processes. Cracks are usually developed during service because of severe plastic deformation and low-cycle fatigue. Thus, the assessment of the deformation severity and remaining life is important for safety operating of the coke drums. This study investigated the bulging damage and fatigue life of 6 coke drums after 16 years and 22 years of service in China. A thermal-mechanical fatigue test were first performed to simulate complex loading condition experienced by the coke drum. The thermal-mechanical fatigue life curve of the fabrication material was obtained. Then, a internal laser scanning was employed to measure the deformation and bulges of drum shells. The finite element analysis was developed to calculate the cyclic stress and strain and bulging severity based on the laser mapping and operating conditions. The fatigue life of the coke drum was assessed by the Coffin-Manson-Basquin’s relationship. The life evaluation results of different methods were compared and analyzed. The results showed that a reasonable life of the coke drum can be obtained by using the thermal-mechanical fatigue properties and laser scanning approach.

A Two Surface Model for Transient Nonproportional Cyclic Plasticity, Part 1: Development of Appropriate Equations

1985 ◽  
Vol 52 (2) ◽  
pp. 298-302 ◽  
Author(s):  
D. L. McDowell
Keyword(s):  
Plastic Strain ◽  
Kinematic Hardening ◽  
Strain Range ◽  
Cyclic Plasticity ◽  
Plastic Strain Rate ◽  
Internal Variables ◽  
Surface Model ◽  
Fading Memory ◽  
Plastic Strain Range ◽  
Hardening Modulus

A two surface stress space model is introduced with internal state variable repositories for fading memory of maximum plastic strain range and non-proportionality of loading. Evolution equations for isotropic hardening variables are prescribed as a function of these internal variables and accumulated plastic strain, and reflect dislocation interactions that occur in real materials. The hardening modulus is made a function of prior plastic deformation and the distance of the current stress point from the limit surface. The kinematic hardening rules of Mroz and Prager are used for the yield and limit surfaces, respectively. The structure of the model is capable of representing essential aspects of complex nonproportional deformation behavior, including direction of the plastic strain rate vector, memory of plastic strain range, cross-hardening effects, variation of hardening modulus, cyclic hardening or softening, cyclic racheting, and mean stress relaxation.

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