12 research outputs found
Welding defects at friction stir welding
The paper presents an overview of different types of defects at friction stir welding. In order to explain the reasons for their occurrence a short theoretical background of the process is given first. The main emphasis is on the parameters that influence the process. An energy supply based division of defects into three disjoint groups was used. The occurring defects are demonstrated on various materials
Direct quality prediction in resistance spot welding process: Sensitivity, specificity and predictive accuracy comparative analysis
In this work, several of the most popular and state-of-the-art classification methods are compared as pattern recognition tools for classification
of resistance spot welding joints. Instead of using the result of a non-destructive
testing technique as input variables, classifiers are trained directly with the
relevant welding parameters, i.e. welding current, welding time and the type of
electrode (electrode material and treatment). The algorithms are compared in
terms of accuracy and area under the receiver operating characteristic (ROC)
curve metrics, using nested cross-validation. Results show that although there is not a dominant classifier for every specificity/sensitivity requirement, support vector machines using radial kernel, boosting and random forest techniques obtain the best performance overallSpanish MICINN Project CSD2010-00034 (SimulPast CONSOLIDER-INGENIO 2010) and by the Junta de Castilla y León GREX251-200