Fatigue surface crack propagation and intersecting cracks in connection with welding residual stresses

2018 ◽  
Author(s):  
A.S. Chernyatin ◽  
Yu.G. Matvienko ◽  
I.A. Razumovsky
Keyword(s):  
Residual Stresses ◽  
Crack Propagation ◽  
Surface Crack

Analysis of Fatigue Crack Propagation in Typical Welded Joints of FPSOs

2005 ◽  
Author(s):  
Bin Zhang ◽  
Torgeir Moan
Keyword(s):  
Stress Intensity ◽  
Residual Stresses ◽  
Crack Propagation ◽  
Analytical Model ◽  
Surface Crack ◽  
Welded Joints ◽  
Structural Reliability ◽  
Fatigue Cracks ◽  
Integral Approach ◽  
Initial Surface

The purpose of this paper is to predict crack propagation and especially the remaining life after through-the-thickness crack at typical joints in deck and bottom structures of FPSOs. This information can be used in planning inspection, repair and maintenance. The growth of fatigue cracks is studied in typical welded joints through the use of analytical and numerical methods. The simplified analytical model is based on the British Standard 7910 [3] and Dexter’s analytical model [1–2]. Numerical analysis is performed with the finite element method, considering the effect of residual stresses, and using the J-integral approach to determine the stress intensity factor at the crack tip during different stages of crack growth. The first stage is referred the surface crack stage, in which the crack grows from an initial surface crack of a size of about 0.1 mm in depth and 0.2mm-1.0mm in length to the through-thickness crack. The second stage is named the long crack stage, in which the crack grows from an approximately 40–100mm long through-thickness crack to the final critical long crack. The computed stress intensity factors, along with the Paris law, are used to predict the crack propagation at each stage with reasonable accuracy. The effect of welding residual stresses on fatigue behaviour is considered by introducing an effective SIF concept. It is concluded that stable crack propagation behaviour can be conservatively predicted by using relatively simple approaches. These techniques can be used in making rational decisions regarding scheduling of inspections, repairs, and allow a better prediction of the structural reliability in view of fatigue cracks.

Influence of the Interface and Residual Stresses on the Apparent Fracture Toughness of Layered Ceramic Composites Based on Alumina-Zirconia

2014 ◽  
Vol 606 ◽  
pp. 209-212
Author(s):  
Luboš Náhlík ◽  
Bohuslav Máša ◽  
Pavel Hutař
Keyword(s):  
Residual Stresses ◽  
Crack Propagation ◽  
Ceramic Composites ◽  
Layered Composites ◽  
Material Interfaces ◽  
Linear Elastic ◽  
Apparent Fracture Toughness ◽  
Elastic Fracture ◽  
Layered Ceramic ◽  
Good Agreement

This paper deals with the fracture behaviour of layered ceramic composite with residual stresses. The main goal is to investigate the effect of residual stresses and material interfaces on crack propagation by more complex 3D finite element models. The crack behaviour was described by analytical procedures based on linear elastic fracture mechanics (LEFM) and generalized LEFM. The influence of laminate composition with residual stresses on critical values for crack propagation through the laminate interfaces was also determined. Good agreement has been found to exist between numerical results and experimental data. The results obtained can be used for a design of new layered composites with improved resistance against crack propagation.

Short Crack Propagation Model Applied to Shot Peened Aluminium Alloys

2009 ◽  
Vol 65 ◽  
pp. 53-61 ◽  
Author(s):  
J. Solis ◽  
J. Oseguera-Peña ◽  
I. Betancourt
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Crack Propagation ◽  
Aluminium Alloys ◽  
Micromechanical Model ◽  
High Strength ◽  
Crack Arrest ◽  
Propagation Model ◽  
Safe Load ◽  
Compressive Residual Stresses

The Navarro-Rios micromechanical model was used to assess the bounds of two different damage zones: crack arrest region and crack propagation region of controlled shot peening (CSP) of high strength aluminium alloys. Performance of CSP in terms of fatigue resistance was investigated. This comparison indicated that CSP in terms of fatigue depends on the competition between its beneficial and detrimental products, i.e. surface roughness and compressive residual stresses respectively. The gathered information can be used for safe load determinations in design.

Study of Influence of Residual Stresses on Crack Propagation in Particulate Ceramic Composites

2016 ◽  
Vol 258 ◽  
pp. 178-181 ◽  
Author(s):  
Zdeněk Majer ◽  
Luboš Náhlík ◽  
Kateřina Štegnerová ◽  
Pavel Hutař ◽  
Raúl Bermejo
Keyword(s):  
Residual Stresses ◽  
Crack Propagation ◽  
Element Model ◽  
Ceramic Composites ◽  
Particulate Composites ◽  
Micro Cracks ◽  
Dimensional Finite Element ◽  
Density Factor ◽  
Energy Density Factor

The aim of the present work is to analyze the influence of residual stresses in the particulate ceramic composite on the crack propagation. The crack propagation direction was estimated using Sih’s criterion based on the strain energy density factor. A two-dimensional finite element model was developed for determination of crack path. The residual stresses resulting from the mismatch of coefficients of thermal expansion during the fabrication process of the composite were implemented to the computational model. The effect of the particles shape on the crack propagation was investigated. Conclusions of this paper can contribute to a better understanding of the propagation of micro-cracks in particulate composites in the field of residual stresses.

Sign in / Sign up

Export Citation Format

Share Document