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Thermal stratification of pressurizer surge line induced by the inside fluid brings on global bending moments, local thermal stresses, unexpected displacements and support loadings of the pipe system. In order to confirm the structural integrity of pressurizer surge line affected by thermal stratification, this paper theoretically establishes thermal stratified transient and studies the calculation method of thermal stratified stress. A costly three-dimensional computation is simplified into a combined 1D/2D technique. This technique uses a pipe cross-section for computation of local thermal stresses and represents the whole surge line with one-dimensional pipe elements. The 2D pipe cross-section model is used to compute elastic thermal stresses in plane strain condition. Symmetry allows half the cross-section to be considered. The one-dimensional pipe elements model gives the global bending moments including effects of usual thermal expansion and thermal stratification of each model nodes. This combined 1D/2D technique has been developed and implemented to analyze the thermal stratification and fatigue stress of pressurize surge line in this paper, using computer codes SYSTUS and ROCOCO. According to the mechanical analysis results of stratification, the maximum stress and cumulative usage factor are obtained. The stress and fatigue intensity of the surge line tallies with the correlative criterion.Copyright © 2010 by ASME

Coupling structure interconnected by hysteretic dampers appears to be an effective method to mitigate structural seismic response. In the paper, the random seismic response is evaluated through the pseudo-excitation principle incorporated with stochastic equivalent linearization method without by solving the Lyapunov differential equation. For which, the seismic excitation is limited to be shot noise process and the computation burden should not be neglected while structural freedoms are large. In the paper, it is supposed that the structures keep elastic all the time and the hysteretic dampers are represented with versatile Bouc-Wen model. With the participation of assistant augment and reduced matrices which are correlated with the location of hysteretic dampers, the unidirectional excitation of one component and spatial excitation of multiple components are derived and the relationship between the pseudo-excitation and pseudo-response is deduced. Then, a pseudo-excitation closed-form expression for the system random response is established. Consequently, the stationary random seismic response of two shear type structure interconnected with hysteretic dampers is analyzed. The structural stationary seismic responses for two methods agree well. parametric studies for the hysteretic dampers and the optimum way to install the hysteretic dampers are also discussed.