scholarly journals Proposal on Unstructured Triangular Mesh Generation Method for Singular Stress Field Analysis of Bonded Structures Based on Finite Element Method

2017 ◽  
Vol 66 (11) ◽  
pp. 853-860
Author(s):  
Takahiko KURAHASHI ◽  
Kengo YAMAGIWA
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Field ◽  
Mesh Generation ◽  
Triangular Mesh ◽  
Field Analysis ◽  
Singular Stress ◽  
Singular Stress Field ◽  
Stress Field Analysis ◽  
Unstructured Triangular Mesh

scholarly journals Fatigue Life Prediction of Welded Joint by Microstructure-based Simulation

2019 ◽  
Vol 269 ◽  
pp. 03005
Author(s):  
Takayuki Shiraiwa ◽  
Fabien Briffod ◽  
Manabu Enoki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Life ◽  
Stress Field ◽  
Butt Joint ◽  
Field Analysis ◽  
Computational Techniques ◽  
Stress Field Analysis ◽  
Number Of Cycles ◽  
Element Method

This paper proposes a numerical framework to predict fatigue life on welded joints by integrating several computational techniques. The framework consists of five steps: i) materials properties estimation; ii) welding simulation using thermo-mechanical finite element method; iii) macroscopic stress field analysis under cyclic loading; iv) mesoscopic stress field analysis using crystal plasticity finite element method (CPFEM); v) analysis of fatigue crack growth. The total number of cycles to failure is eventually obtained by the sum of initiation life calculated by CPFEM and propagation life calculated by X-FEM. A fatigue life of butt joint is evaluated by the proposed method. The results demonstrated the possibility of evaluating the fatigue life and its scattering by the proposed framework.

The Stress Calculating and Analysis of the Second HP Turbine Disc of a Certain Type of Aeroengine

2013 ◽  
Vol 331 ◽  
pp. 176-180
Author(s):  
Ke Jun Xu ◽  
Yong Qi Wang ◽  
Yi Rui Xia ◽  
Ming Ming Jia
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Element Model ◽  
Life Assessment ◽  
Field Analysis ◽  
Finite Element Software ◽  
Turbine Disc ◽  
Stress Field Analysis ◽  
Numerical Calculation Method ◽  
Element Theory

This paper takes the 2nd HP turbine disc of an aeroengine as research object, construct its finite element model in software-Patran. According to the work environment of 2nd HP turbine disc, the boundary conditions of stress field analysis and temperature field analysis are confirmed. Based on the finite element theory of thermal analysis and structure analysis, we use finite element software-Nastran to analyze centrifugal stress and thermal stress. Numerical calculation method was used to fit the data and finally we got the thermal elastic stress field. According to the computed results, the life assessment points of disc were confirmed. The static strength of 2nd HP turbine disc was tested based on the EGD-3 criterion. All the work established the foundation for subsequent life analysis.

Fatigue Pre-Cracking Curved Wide Plates in Bending

2010 ◽  
Author(s):  
Mark D. Richards ◽  
Timothy S. Weeks ◽  
J. David McColskey ◽  
Bo Wang ◽  
Yong-Yi Wang
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Stress Field ◽  
Crack Growth ◽  
Field Analysis ◽  
Four Point Bending ◽  
Stress Field Analysis

Curved wide plate (CWP) testing in tension, on API 5L X100 pipes of 36-inch (916-mm) diameter and 0.75-inch (19-mm) wall thickness, has been initiated in support of strain-based design using high strength steel for oil and gas pipeline applications. The CWP tests are being used to optimize and validate welding procedures and to determine the defect tolerance within the girth welds. A traditional pre-requisite for fracture mechanics testing is a final extension of a crack via fatigue pre-cracking to produce a representative flaw. A method of fatigue pre-cracking CWP specimens for final notch preparation in bending was developed to meet ASTM guidelines for fracture mechanics testing. Fatigue pre-cracking for the present specimen geometry was possible in bending due to lower requisite force capacity equipment which allowed for greater cyclic loading frequencies. In order to achieve sufficient stress levels for fatigue crack growth in the curved plate, a stress field analysis was performed to optimize the loading support configuration in four-point bending. In addition to the stress field analysis, a 3-D finite element model of the CWP specimen was generated to analyze the notched CWP specimen in four-point bending. Finite element analysis (FEA) results and experimental data were used to confirm the hypothesis that, under the proposed loading arrangement, the closed-form solutions for stress-intensity (K) of flat plates in bending can be used to approximate the K for CWP specimens in bending. Validation of a solution for stress-intensity factor subsequently allowed the determination of force amplitude levels for fatigue crack growth. Force and crack mouth opening displacement (CMOD) data were analyzed to correlate compliance with crack length measurements. From experimental results, a method was developed that enable the repeatable and well characterized extension of surface flaws by fatigue pre-cracking in curved wide plate specimens in bending.

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