When a wellhead gas production tree in a certain oilfield block fracturing completed 12 layers and 22 layers and then the bottom-up discharge operation was performed, the Wellhead four-way suddenly suffered erosion failure. This is the seventh failure of this operation. In order to obtain the cause of failure, the chemical analysis, hardness testing, tensile property testing, and finite element structural dynamic analysis are used to analyze the failure of the cross connection. The results of physical and chemical analysis show that the chemical composition, hardness, and tensile properties of the failed parts meet the requirements of the standard, not the problem of the material of the work piece. Due to the high-frequency vibration generated by the three-phase fluid in the pipeline during the discharge process, different types of vibration and deformation of the four-way valve and the valve body occur. The dimensions of the on-site structural parts were measured, and the bolt sizes were found to be different. A finite element model was established based on the measured data for dynamic analysis. Through physical and chemical tests and theoretical calculations, it is found that the cause of failure is the unbalanced load and resonance of the bolt, and the nut undercuts under high-frequency vibration, which causes leakage at the flange connection and eventually causes erosion failure. It is recommended to regularly use an electronic torque wrench to test the pretightening force of each bolt to prevent vibration and failure due to inconsistent pretightening force of the bolts.
At present, when the ultra -long linear 3D model is loaded in the 3D scene, it is difficult to adapt the ultra -long line model to the terrain model due to the influence of projection distortion. At present, some solutions mainly focus on the model rendering level, without considering the necessity of linear engineering construction, which is hard to encounter the requirements of 3D visualization in the meadow of linear engineering management. Therefore, this paper conducts research from two aspects of projection distortion calculation and analysis, linear engineering independent coordinate system establishment and so on, and puts forward the method of line model loading based on linear independen t coordinate system piecewise technology. Firstly, the linear engineering projection distortion is calculated and analyzed. Then, based on the requirements of linear engineering construction accuracy, multiple independent coordinate systems that meet the a ccuracy requirements are constructed according to the characteristics of linear engineering. Finally, the 3D model of the ultra -long line is piecewise loaded, and the influence caused by the distortion of the projection length is apportioned through each independent coordinate system. The practical consequence indicate that this method can virtually optimize the difficult problem of model and terrain acclimatization caused by projection distortion, and meet the rendering requirements of linear engineering 3D models.
Aiming at the problems of complex scene objects, lack of correlation between them, close coupling between modelling knowledge and modelling process, and low flexibility of scene configuration in dam safety monitoring scene construction, this paper proposes a multi-level semantic constraint method for dam safety monitoring scene construction. First, based on the analysis of the characteristics of dam safety monitoring scene modelling operations and modelling knowledge expression, modelling knowledge is extracted from spatial pose semantic constraints, spatial layout semantic constraints and component combination semantic constraints, and modelling knowledge and modelling operations are stored in a parametric way. Then, after the multi-level semantic constraint rules constrain and guide the way the scenario objects are combined, the dam safety monitoring scenario is generated. A prototype dam safety monitoring system is developed based on this approach to validate the effectiveness of the method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.