Numerical simulation of crack propagation in bimetallic spatial structures

• Main Authors: Олександр Володимирович Гондлях, Роман Євгенович Нікітін, Владислав Юрійович Онопрієнко
• Format: Article
• Language: English
• Published: PC Technology Center 2014-05-01
• Series: Tehnologìčnij Audit ta Rezervi Virobnictva
• Subjects: destruction; bimetallic distillation column; crack; numerical simulation; APROKS
• Online Access: http://journals.uran.ua/tarp/article/view/25276

The chemical industry uses welded bimetallic vessels and apparatuses that periodically run repair process. Violating welding procedure may cause defects that may lead to destruction of bimetallic vessels and apparatuses. There are cases of destruction of bimetallic vessels and apparatuses at loads much lower than planned. Therefore, identifying and investigating defects in the structure at the design stage to prevent accidents by modeling the processes, connected with the destruction is an important issue. Destruction under comparison has emerged in the case of the distillation column with a diameter of 3200 mm and a wall thickness of 28 mm (in the destruction zone) at a pressure of 1.2 MPa. Herewith, a crack with the length of ~ 6.6 m and an opening width of up to 120 mm has developed. The column material is plastic, so the crack development runs within a certain time. Crack propagation process is non-linear and crack development time-dependent, which in turn affects the internal pressure and crack propagation rate. Air losses are found using the known ratio, which takes into account the loss factor, crack opening surface area, absolute pressure in the column and temperature. In the paper it was assumed that crack opening growth under Irvine is half of the plastic zone and depends on the tangential stresses in the column, crack length and plastic limit for the column material. Based on a complex APROKS, a model of crack propagation in bimetallic structures was developed. Numerical simulation of the crack propagation process is carried out in the work by integrating the equations of motion in time depending on the crack development parameters. The system APROKS can be recommended for practical implementation in the design and operation of equipment for chemical engineering and petroleum industry.