Porosity Attributes Research Articles

Study of micro-porosity in electron beam butt welding

As complete elimination of porosity from the weld is very difficult, the next option available is to minimize this weld porosity, which is crucial for the safe performance of the welded components. However, this investigation through experiments alone is very tedious and time consuming. Additionally, very limited models are available in the literature for accurate prediction of different porosity attributes. The present study, thus, addressees both the experimental as well as modelling aspect on the study of micro-porosity during electron beam welding (EBW) of SS304 plates. Welding parameters are reported to have significant influence on the micro-porosity. Hence, the influences of these parameters on micro-porosity attributes, namely pores number, average diameter, and sphericity are extensively studied experimentally employing optical microscopy (OM), scanning electron microscopy (SEM), X-ray computed tomography (XCT), and Raman spectroscopy. This is followed by an elaborate modelling using seven popular and well-recognized machine learning algorithms (MLAs), namely multi-layer perceptron (MLP), support vector regression (SVR), M5P model trees regression, reduced error pruning tree (REPTree), random forest (RF), instance-based k-nearest neighbor algorithm (IBk), and locally weighted learning (LWL). These different techniques enhance the chance of obtaining the better predictions of the said micro-porosity attributes by overcoming the effect of data-dependence and other limitations of individual MLAs. The different model-predicted micro-porosity data are also validated through experimental data. Statistical tests and Monte-Carlo reliability analysis are additionally utilized to evaluate the performances of the employed algorithms. IBk and MLP are overall found to perform well.

Slope stability analysis using Universal Distinct Element Code (UDEC) method

Slope stability analysis was conducted using the Universal Distinct Element Code (UDEC) technique in this research. This technique stimulates the spread of stress waves in the jointed rock mass owing to dynamic loading caused by the blast. Simulation is a vital component of the slope stability analysis, as it generates a model called discontinuum capable of simulating the movement of fragments owing to the burst of production. Besides, the discontinuous codes used in this analysis may duplicate the entire method of fragmentation of the rock from fracture to fragment throw. This discontinuous analysis can also simulate joints and porosity attributes in a rock mass.