scholarly journals An algorithm for statistical evaluation of weld toe geometries using laser triangulation

2021 ◽  
Author(s):  
Finn Renken ◽  
Rüdiger Ulrich Franz von Bock und Polach ◽  
Jan Schubnell ◽  
Matthias Jung ◽  
Markus Oswald ◽  
...  
Keyword(s):  
Statistical Evaluation ◽  
Sampling Rate ◽  
Small Scale ◽  
Laser Triangulation ◽  
Weld Quality ◽  
Weld Geometry ◽  
Weld Toe ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Modal Values

Commonly, to evaluate the influence of the local weld geometry in fatigue test, small-scale specimens are used, assuming those represent a longer weld adequately. In this study, a comparison between short specimens and a long weld is performed. A method is developed for the statistical evaluation of weld toe radii and angles, stress concentration factors and weld quality classes. The results show a strong sampling rate dependence and lower ISO 5817:2014 weld quality results for higher sampling rates. Comparable results between short specimens and a long weld can be achieved using modal values of the parameters assuming a lognormal distribution.

scholarly journals Stress Concentration Factors for Welded Plate T-Joints Subjected to Tensile, Bending and Shearing Loads

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 546
Author(s):  
Krzysztof L. Molski ◽  
Piotr Tarasiuk
Keyword(s):  
Stress Concentration ◽  
Plate Thickness ◽  
Percentage Error ◽  
Geometrical Parameters ◽  
T Joints ◽  
Loading Mode ◽  
Weld Toe ◽  
Concentration Factors ◽  
Parametric Expression ◽  
Stress Concentration Factors

The paper deals with the problem of stress concentration at the weld toe of a plate T-joint subjected to axial, bending, and shearing loading modes. Theoretical stress concentration factors were obtained from numerical simulations using the finite element method for several thousand geometrical cases, where five of the most important geometrical parameters of the joint were considered to be independent variables. For each loading mode—axial, bending, and shearing—highly accurate closed form parametric expression has been derived with a maximum percentage error lower than 2% with respect to the numerical values. Validity of each approximating formula covers the range of dimensional proportions of welded plate T-joints used in engineering applications. Two limiting cases are also included in the solutions—when the weld toe radius tends to zero and the main plate thickness becomes infinite.

Stress Concentration Factors of Dented Pipelines

2006 ◽  
Author(s):  
Bianca de Carvalho Pinheiro ◽  
Ilson Paranhos Pasqualino ◽  
Se´rgio Barros da Cunha
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Numerical Model ◽  
Finite Element Model ◽  
Internal Pressure ◽  
Element Model ◽  
Small Strain ◽  
Small Scale ◽  
Concentration Factors ◽  
Stress Concentration Factors

A nonlinear finite element model was developed to assess stress concentration factors induced by plain dents on steel pipelines subjected to cyclic internal pressure. The numerical model comprised small strain plasticity and large rotations. Six small-scale experimental tests were carried out to determine the strain behavior of steel pipe models during denting simulation followed by the application of cyclic internal pressure. The finite element model developed was validated through a correlation between numerical and experimental results. A parametric study was accomplished, with the aid of the numerical model, to evaluate stress concentration factors as function of the pipe and dent geometries. Finally, an analytical formulation to estimate stress concentration factors of dented pipelines under internal pressure was proposed. These stress concentration factors can be used in a high cycle fatigue evaluation through S-N curves.

Alternate Design Solutions for Reduced Stress Concentration Factor (SCF) T Joints of Circular Hollow Structures

2014 ◽  
Vol 1029 ◽  
pp. 44-49
Author(s):  
Gabriel Dima ◽  
Teodor Machedon-Pisu ◽  
Ion Balcu
Keyword(s):  
Stress Concentration ◽  
Analytical Calculation ◽  
Tubular Structures ◽  
Element Analysis ◽  
Hollow Structures ◽  
Development Teams ◽  
Practical Design ◽  
Weld Toe ◽  
Concentration Factors ◽  
Stress Concentration Factors

Design for fatigue of lightweight welded tubular structures is a significant concern of development teams. Based on practical design experience, alternate T joint design to usual Circular Hollow Structures (CHS) T joins are proposed. Proposed designs employ formed members within relevant dimensions range. A method based on finite element analysis including weld modelling was used, with analytical calculation of weld toe stress. Stress concentration factors (SCF) are calculated for all proposed designs for all typical load cases. Best placement and dimensions of formed members is given, together with design recommendations.

Stress Concentration Factors of Longitudinal and Transverse Plain Dents on Steel Pipelines

2008 ◽  
Author(s):  
Bianca C. Pinheiro ◽  
Ilson P. Pasqualino
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Internal Pressure ◽  
High Cycle Fatigue ◽  
Element Model ◽  
Small Scale ◽  
Assessment Methodology ◽  
Cycle Fatigue ◽  
Concentration Factors ◽  
Stress Concentration Factors

The objective of this work is to evaluate the stress concentration induced by longitudinal and transverse plain dents on steel pipelines under cyclic internal pressure. This work is within a study to propose a new methodology to assess the fatigue life of dented steel pipelines based on the current high cycle fatigue theory. This methodology employs stress concentration factors induced by plain dents, which are used to modify material S-N curves of metallic structures under high cycle fatigue loadings. The proposed assessment methodology was validated according to small-scale fatigue test results of steel pipe models with spherical dents under cyclic internal pressure. Here, stress concentration factors induced by longitudinal and transverse plain dents on steel pipes under internal pressure are obtained from a previously developed finite element model. Several finite element analyses are carried out in a parametric study. Analytical expressions are developed to estimate stress concentration factors for these two different dent geometries as function of pipe and dent geometric parameters. With the inclusion of these expressions, the proposed assessment methodology is improved and is now able to deal with three different plain dent geometries: spherical, longitudinal and transverse dents.

High Cycle Fatigue of Pipelines With Plain Dents: Simulations, Experiments and Assessment

2007 ◽  
Author(s):  
Se´rgio B. Cunha ◽  
Bianca C. Pinheiro ◽  
Ilson P. Pasqualino
Keyword(s):  
Stress Concentration ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Test Material ◽  
Small Scale ◽  
Test Results ◽  
Cycle Fatigue ◽  
Concentration Factors ◽  
Stress Concentration Factors

The objective of this work is to propose a methodology for assessing the fatigue life of dented pipelines according to the current high cycle fatigue theory. The proposed methodology employs S-N curves obtained from tensile test material properties and includes an expression to estimate stress concentration factors for spherical dents. Finite element analyses are carried out to determine stress concentration factors for different pipe and dent geometries. Using the numerical results, an expression to estimate stress concentration factors of dented pipelines is developed. Additionally, fatigue tests are conducted with the application of cyclic internal pressure on small-scale dented steel pipe models. Different pressure levels are employed, resulting in failures ranging from around 6000 to more than 106 cycles, enabling the determination of the endurance limit and of the finite life behavior of dented pipes. Furthermore, the Goodman and Gerber criteria to account for the mean stress are evaluated in view of the experimental results. The fatigue test results are used to validate the proposed assessment methodology for the analyzed conditions.

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.

scholarly journals An algorithm for statistical evaluation of weld toe geometries using laser triangulation

2021 ◽  
pp. 106293
Author(s):  
Autors: Finn Renken ◽  
Rüdiger Ulrich Franz von Bock und Polach ◽  
Jan Schubnell ◽  
Matthias Jung ◽  
Markus Oswald ◽  
...  
Keyword(s):  
Statistical Evaluation ◽  
Laser Triangulation ◽  
Weld Toe
Sign in / Sign up

Export Citation Format

Share Document