1,721,362 research outputs found
A quantitative assessment of the residual stress effects on fatigue crack propagation in structural steel weldments in air and seawater
No full textA PROTOTYPE EXPERT-SYSTEM FOR EMBODIMENT DESIGN OF MECHANISMS AND ARTICULATED SYSTEMS
No full textThe embodiment phase plays a significant role in mechanical design, particularly in the case of mechanisms and articulated systems. In order to investigate the capabilities offered by artificial intelligence techniques for the automation of this design stage, a prototype expert system (ES), called EMBMEC, was developed. The ES possesses a 'hybrid' structure, making use of both symbolic inference and numerical calculation techniques. At present, it can operate with plane mechanisms, selecting materials, link geometry and bearings. In the paper, the most relevant features of the system are discussed and a simple application example is reported
LIFE PREDICTIONS BY 3 CREEP FATIGUE INTERACTION MODELS - INFLUENCE OF MULTIAXIALITY AND TIME-VARIABLE LOADINGS
No full textLife predictions given by three creep-fatigue damage models, namely the 'continuous damage model', the 'damage rate approach' and the 'time and cycle fractions summation' method, were evaluated for over 200 high temperature fatigue tests reported in the literature. These tests, which were conducted on AISI 304 and 316 stainless steels, include several different multiaxial and time-variable loading conditions (in-phase and out-of-phase biaxial stress, various strain waveforms, complex loading histories, etc.) whose influence on the distribution of the ratio between predicted and observed cycles to failure was analysed. Results obtained by the three models are discussed, emphasizing differences in accuracy and cases in which the creep-fatigue behaviour does not appear to be satisfactorily predicted
INFLUENCE OF SEAWATER AND RESIDUAL-STRESSES ON FATIGUE CRACK-GROWTH IN C-MN STEEL WELD JOINTS
No full textResults are presented on fatigue crack growth of weld joints made of C-Mn structural steel plates in both air and seawater. Tests were conducted to identify the behavior at different locations of the joints as the frequency, R-ratio and electrochemical potential are varied. Residual stresses in specimens with welds are evaluated to analyse the fatigue crack growth behavior. Satisfactory predictions are obtained by accounting for residual stresses and crack closure
Corrosion Fatigue Crack Growth Rate in a C-Mn Steel and in its Welded Joints in Seawater
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A Comparison of Three Creep-Fatigue Life Prediction Models under Several Different Loading Conditions
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