The prediction of exact behavior for loadings such as earthquakes, explosions, and other catastrophic conditions is required to confirm safety of piping systems. A joint model is developed for efficient analysis of piping systems with joint deformation in this study.
The piping systems are idealized as assemblages of beam elements interconnected by joint. the developed joint model consists of two elements: 1) element I compose of rigid body with axial stiffness only to consider ovalization effects which occur owing to hollow circular section in pipe. 2) element II compose of two elastic rotational spring account for additional two degrees of freedom in joint.
The matrix condensation technique is employed to obtain the stiffness matrix with degrees of freedom regard to only translations for the reduction of degrees of freedom which results in significant saving in computational efforts and required memories.
The results of analyses for several example piping systems are compared to those obtained by using three dimensional finite element models for verification of the accuracy and efficiency of the joint models utilizing computer program DYPS developed in this study.
Three stiffness coefficients which is account for joint deformation are needed in order to use a joint model. The developed joint model in this study can be used as an efficient and accurate means for the analysis of piping systems. The acquired results using the joint models can apply to local models of piping systems. The acquired results using the joint models can apply to local models of piping systems so as to predict fatigue damage which may occur by cyclic loadings at joint.
