Natural frequencies and vibration modes of tank's protective capacitance with weld defects under axial static load

The natural frequencies and vibration modes of tank's protective capacitance with welded joints defects under axial static load are determined in order to construct a diagnostic model monitor the propagation. Computer simulation dynamic behavior using computer finite element analysis system NASTRAN was performed. design form cylindrical thin-walled shell allowance for belts from weld rolled sheet built. Weld as two through horizontal cracks located welds between first second were presented. crack width equaled sheets diameter. For assessing effect propagation on characteristics length increased until single continuous crack. allowed generalize different types predict critical state. Determination performed stages. At stage, stress-strain state nonlinear formulation investigated total stiffness matrix (linear geometric) formed. problem approximation Lagrange possible displacements principle formulated. Newton-Raphson stepwise loading method (Nonlinear Static) used. by Lanczos (Param Modes) solving eigenvalue problem. action evaluated. results showed that presence an their increase reduced values frequencies. compressive thin wall can both reduce its rigidity, thereby changing frequency modes. According authors, consideration such should be present calculations shells, especially stochastic loads (wind, seismic, etc.).