scholarly journals Robust Mesh Insensitive Structural Stress Method for Fatigue Analysis of Welded Structures

2013 ◽  
Vol 55 ◽  
pp. 374-379 ◽  
Author(s):  
P. Selvakumar ◽  
J.K. Hong
Author(s):  
Gürkan İrsel

In this study, the total algorithm of the strength-based design of the system for mass production has been developed. The proposed algorithm, which includes numerical, analytical, and experimental studies, was implemented through a case study on the strength-based structural design and fatigue analysis of a tractor-mounted sunflower stalk cutting machine (SSCM). The proposed algorithm consists of a systematic engineering approach, material selection and testing, design of the mass criteria suitability, structural stress analysis, computer-aided engineering (CAE), prototype production, experimental validation studies, fatigue calculation based on an FE model and experimental studies (CAE-based fatigue analysis), and an optimization process aimed at minimum weight. Approximately 85% of the system was designed using standard commercially available cross-section beams and elements using the proposed algorithm. The prototype was produced, and an HBM data acquisition system was used to collect the strain gage output. The prototype produced was successful in terms of functionality. Two- and three-dimensional mixed models were used in the structural analysis solution. The structural stress analysis and experimental results with a strain gage were 94.48% compatible in this study. It was determined using nCode DesignLife software that fatigue damage did not occur in the system using the finite element analysis (FEA) and experimental data. The SSCM design adopted a multi-objective genetic algorithm (MOGA) methodology for optimization with ANSYS. With the optimization solved from 422 iterations, a maximum stress value of 57.65 MPa was determined, and a 97.72 kg material was saved compared to the prototype. This study provides a useful methodology for experimental and advanced CAE techniques, especially for further study on complex stress, strain, and fatigue analysis of new systematic designs desired to have an optimum weight to strength ratio.


1999 ◽  
Author(s):  
Haruo Sakamoto

Abstract This paper describes the codes and practice for designing welded structures such as railroad truck frames. For designing the first configuration, rather simple criteria are desired, although most codes such as AWS. AISC, etc. are complex. They consist of a variety of welded joint categories, which make a designer feel uncomfortable when deciding the first configuration. Therefore, such codes are considered to be mainly used for the evaluation of designed and constructed structures, and not to be used for deciding the first configuration. The JIS (Japanese Industrial Standard) for a railroad truck frame is explained as an example of a simple code, and is compared with some fatigue data. This standard is thought to be useful for a designer. However, the result of this investigation suggests a modification of the JIS for obtaining more reasonable criteria. Desirable criteria should be simple for a designer and sufficiently safe for structures. Additional investigations on fatigue data of welded joints, a statistical study for desirable non-fracture probability, and methods of structural stress analysis are to be conducted in the future. A practical fatigue testing method is also needed for investigating the strength in a high cycle region such as 108.


Author(s):  
Brian E. Healy

A spectral fatigue analysis using both the surface extrapolation and Battelle structural stress methodologies has been performed on a side shell connection detail typical of a representative FPSO or tanker vessel. This marks the first time the Battelle method has been adapted to spectral fatigue and details of the implementation are presented for narrow banded applications. Fatigue damage at the toe along a number of weld lines is computed for a variety of surface extrapolation strategies and Battelle method options. Results are reported and compared. Recommendations regarding the application of the Battelle method to spectral fatigue are made.


2013 ◽  
Vol 838-841 ◽  
pp. 314-318
Author(s):  
Hang Gang Guo ◽  
Jin Zhang ◽  
Yang Zhang ◽  
Wei Zhang

Though fatigue failure is often happened in steel gate, fatigue design has not yet been included in design or evaluation standards in China. In this paper, analytical theory based structural stress method and structural stress based fatigue analysis method are combined and employed for fatigue life evaluation of plane steel gate. The variation of water head is taken into consideration for the conditions of gate running and resting. In order to give a valid evaluation, the weld located among all components is considered as rigid connection when calculating structural stress. Master S-N curve in ASME code is used for life evaluation. Example shows the method can be used for fatigue analysis of plane steel gate, and can be used to identify fatigue failure zone.


2005 ◽  
Author(s):  
Tsuneaki Kaneko ◽  
Akifumi Okabe ◽  
Noboru Tomioka

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