Fatigue life analysis of hydropower pipelines using the analytical model of stress concentration in welded joints with angular distortions and considering the influence of water hammer damping

2021 ◽  
Vol 159 ◽  
pp. 107350
Author(s):  
Adam Adamkowski ◽  
Mariusz Lewandowski ◽  
Stanisław Lewandowski
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Analytical Model ◽  
Welded Joints ◽  
Water Hammer ◽  
Influence Of Water ◽  
Life Analysis ◽  
Fatigue Life Analysis

Strain-based fatigue life analysis of pipelines with external defects under cyclic internal pressure

2020 ◽  
pp. 030932472095756
Author(s):  
Hojjat Gholami ◽  
Shahram Shahrooi ◽  
Mohammad shishehsaz
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Plastic Strain ◽  
Internal Pressure ◽  
Oil And Gas ◽  
Isotropic Hardening ◽  
Element Simulation ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Pipe Geometry

Gouge and dent are common mechanical defects in oil and gas pipelines. These defects with plastic strain cause stress concentration in the pipelines. Plastic strain is dependent on initial deformation and spring-back behavior of materials. Therefore, they reduce the fatigue life of pipelines. In this paper, the strain-base fatigue life analysis is investigated in pipelines with smooth dent or combination smooth dent and gouge defects under cyclic internal pressure. For this purpose, elastic-plastic multilinear isotropic hardening finite element simulation was used to investigate the effects of various factors, such as residual stress of dent, amplitude internal pressure, pipe geometry, gouge geometry, and smooth dent geometry on stress concentration factor (SCF). Finally, a new method is proposed for predicting the fatigue life of pipelines with uniform dent and uniform dent and gouge combination defects. The model is presented based on the Smith-Watson-Topper (SWT) criterion. A set of fatigue life test specimens with various pipe materials, size and geometry were prepared and tested. The specimens carried a smooth dent, as well as a combination of smooth dent and gouge defects, results of which were collected to validate those obtained based on the proposed model. The results of the predicted tests using the developed formula showed a good correlation to practical experiments.

Fatigue Life Analysis of T-Type Fillet Welded Joints Using an Effective Notch Stress Method

2020 ◽  
Vol 37 (8) ◽  
pp. 601-606
Author(s):  
Minhyeok Heo ◽  
Changwan Han ◽  
Hanjong Kim ◽  
Seung-bin Jung ◽  
Seonghun Park
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Notch Stress ◽  
Effective Notch Stress ◽  
Life Analysis ◽  
Fatigue Life Analysis

Fatigue Life Analysis of Steel Pipelines With Plain Dents Under Cyclic Internal Pressure

2008 ◽  
Author(s):  
Bianca de Carvalho Pinheiro ◽  
Ilson Paranhos Pasqualino ◽  
Se´rgio Barros da Cunha
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Internal Pressure ◽  
Fatigue Tests ◽  
Small Scale ◽  
Concentration Factors ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Stress Concentration Factors

This work is within an ongoing study, which aims to propose a new methodology for fatigue life analysis of steel pipelines with plain dents under cyclic internal pressure. This methodology follows the current high cycle fatigue theory and employs stress concentration factors induced by plain dents to modify standard S-N curves. A previously developed and validated finite element model is extended to generate stress concentration factors for longitudinal and transverse dents, in addition to spherical dents. Several finite element analyses are carried out in a parametric study to evaluate stress concentration factors induced by the three dent types studied: spherical, longitudinal and transverse dents. Analytical expressions are developed to estimate stress concentration factors for these three dent types as function of pipe and dent geometric parameters. Small-scale fatigue tests are conducted to evaluate the finite life behavior of dented steel pipes under cyclic internal pressure. The methodology is validated in view of the fatigue tests results. Including expressions to estimate stress concentration factors for three different dent types (spherical, longitudinal and transverse dents), the proposed methodology can then be used for fatigue life analysis of dented steel pipelines under cyclic internal pressure.

Fatigue life analysis of shot-peened bearing steel

2012 ◽  
Vol 26 (6) ◽  
pp. 1747-1752 ◽  
Author(s):  
Sang-Jae Yoon ◽  
Jung-Hoon Park ◽  
Nak-Sam Choi
Keyword(s):  
Fatigue Life ◽  
Bearing Steel ◽  
Life Analysis ◽  
Fatigue Life Analysis

scholarly journals Low-cycle fatigue behaviour of laser welded high-strength steel DOMEX 700 MC

2018 ◽  
Vol 157 ◽  
pp. 05013 ◽  
Author(s):  
Peter Kopas ◽  
Milan Sága ◽  
František Nový ◽  
Bohuš Leitner
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
High Strength Steel ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Fatigue Behaviour ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Fatigue Life Analysis

The article presents the results of research on low cycle fatigue strength of laser welded joints vs. non-welded material of high-strength steel DOMEX 700 MC. The tests were performed under load controlled using the total strain amplitude ɛac. The operating principle of the special electro-mechanic fatigue testing equipment with a suitable clamping system was working on 35 Hz frequency. Fatigue life analysis was conducted based on the Manson-Coffin-Basquin equation, which made it possible to determine fatigue parameters. Studies have shown differences in the fatigue life of original specimens and laser welded joints analysed, where laser welded joints showed lower fatigue resistance. In this article a numerical analysis of stresses generated in bending fatigue specimens has been performed employing the commercially available FEM-program ADINA.

Sign in / Sign up

Export Citation Format

Share Document