Study on the integrity detection and evaluation method of damaged pipeline
To detect the integrity of damaged pipeline and accurately evaluate its damaged condition, a CCD image data guided digital automatic ultrasonic testing system was designed to realize the dynamic measurement of a pipeline damaged surface, and extract the characteristic parameter of damaged pipeline. Based on the three-dimensional discrete point set which gathered to describe the integrity of damaged pipeline, we establish a damaged pipeline entity model which is closer to the actual condition, analyze and simulate mechanical properties under the actual load by using the numerical simulation software (ABAQUS), to get the most dangerous region and the trend of stress and displacement. This method provides more reliable reference for integral safety analysis and evaluation of damaged pipeline.
Mechanical Behavior of Spun-Cast Gray Iron Pipe
Past work has made little differentiation between the mechanical properties of pit and spun cast gray iron water pipes. Mechanical tests on coupons from spun and pit cast samples presented here show that spun cast gray iron has mechanical properties that fall between those of pit cast gray iron and ductile iron pipes, often with marked similarities to ductile iron. The properties determined from the mechanical tests were used to examine whether linear elastic analysis can be successfully used to approximate the mechanical behavior of a pipe loaded in bending. Linear elastic analysis was found to produce reasonable approximations to the behavior of undamaged pipes. The effect of corrosion pitting was included in the analysis by determining stress concentration factors for pits of varying depths at different stress levels. Multiplying the stress concentration factors by the results of the linear elastic analysis produced results with an error of no more than 6% from the values produced by a full cast iron p...
A simple pipe bend element for piping flexibility analysis
Abstract The formulation of a simple pipe bend finite element for linear elastic analysis is presented. The element is based on Vlasov's thin-wall curved beam theory with superposed Von Karman ovalisation. The stiffness matrix is given in closed form and hence can be easily incorporated in existing flexibility analysis programs. Four sample analyses using the element are presented. The results are found to compare well with existing theoretical and experimental results, and comparison of model size with other finite element models indicates that the element is economical in computing requirements and offers a viable alternative to flexibiltity analysis in piping design.