Identification of fragmentation mechanism and risk analysis due to explosion of cylindrical tank.

This study presents a completely new methodology for fragmentation analysis due to the explosion of cylindrical tanks. The identification of fragments' kinematic parameters was accomplished with an exact system of differential equations of motion with good convergence and high accuracy of numerical results. The fluctuation effect of the aerodynamic force of the fragments on their range is interpreted by statistical distributions. The direction and intensity of the fragments' initial velocity are determined by the inertial model. An original probabilistic mass method is proposed to represent the discrete distribution of the number of generated fragments. The correlation between the number and mass of the fragments was established by Monte Carlo simulation. The estimation of the fracture lines was carried out by the tank stress mapping procedure using data from the ANSYS software. The identification of potential fracture lines with the knowledge of the number-to-mass dependence of the fragments allows a reliable estimate of the shape of the generated fragments. The estimated sectoral risk due to tank fragmentation is consistent with literary accident data. The presented methodology can be fully applied to the assessment of the risk of other types of tanks and process installations.

Unconventional bearing capacity analysis and optimization of multicell box girders.

This study deals with unconventional bearing capacity analysis and the procedure of optimizing a two-cell box girder. The generalized model which enables the local stress-strain analysis of multicell girders was developed based on the principle of cross-sectional decomposition. The applied methodology is verified using the experimental data (Djelosevic et al., 2012) for traditionally formed box girders. The qualitative and quantitative evaluation of results obtained for the two-cell box girder is realized based on comparative analysis using the finite element method (FEM) and the ANSYS v12 software. The deflection function obtained by analytical and numerical methods was found consistent provided that the maximum deviation does not exceed 4%. Multicell box girders are rationally designed support structures characterized by much lower susceptibility of their cross-sectional elements to buckling and higher specific capacity than traditionally formed box girders. The developed local stress model is applied for optimizing the cross section of a two-cell box carrier. The author points to the advantages of implementing the model of local stresses in the optimization process and concludes that the technological reserve of bearing capacity amounts to 20% at the same girder weight and constant load conditions.

Mathematical identification of influential parameters on the elastic buckling of variable geometry plate.

The problem of elastic stability of plates with square, rectangular, and circular holes as well as slotted holes was discussed. The existence of the hole reduces the deformation energy of the plate and it affects the redistribution of stress flow in comparison to a uniform plate which causes a change of the external operation of compressive forces. The distribution of compressive force is defined as the approximate model of plane state of stress. The significant parameters of elastic stability compared to the uniform plate, including the dominant role of the shape, size, and orientation of the hole were identified. Comparative analysis of the shape of the hole was carried out on the data from the literature, which are based on different approaches and methods. Qualitative and quantitative accordance of the results has been found out and it verifies exposed methodology as applicable in the study of the phenomenon of elastic stability. Sensitivity factor is defined that is proportional to the reciprocal value of the buckling coefficient and it is a measure of sensitivity of plate to the existence of the hole. Mechanism of loss of stability is interpreted through the absorption of the external operation, induced by the shape of the hole.