Curved reflection bunching technology is an effective method to achieve directional radiation of intense acoustic shock wave and improve the acoustic intensity in the designated area for high-power underwater intense sound source. The material properties of reflector are one of the main factors affecting the distribution characteristics of reflection bunching sound field. Based on the nonlinear finite element method, curved reflection bunching and fluid-structure interaction theory, the underwater plasma sound source (UPSS) bunching sound field model is established, and the distribution law of the underwater plasma sound source bunching sound field with different reflector material properties is numerically simulated. The influence of material properties on the performance of ellipsoidal reflector, such as bunching gain, peak pressure of bunching wave and acoustic axis distribution, is analyzed in detail, which provides guidance for further design of reflector, selection of reflector material and improvement of bunching performance parameters.
The technology of firefighting unmanned aerial vehicles (UAVs) used in fire scene reconnaissance, water disaster investigation, and rescue missions, has become a crucial asset in responding to fires and emergencies. The key to this technology is to swiftly and effectively improve the operational efficiency of UAVs. Based on the premise of rapid and effective rescue, the stability, tracking, and safety of hexacopter UAVs technology improved the design and optimization innovative design of the storage and transportation convenience structure of unmanned aerial vehicles were carried out. An innovative high-pressure ejection mechanism for fire bombs (delivery items) has been designed. So, a portable, efficient, and fast unmanned aerial vehicle structure was designed. The PX4 flight control system was used to conduct simulation experiments on the newly designed UAV, and it was found that the structural design was reasonable, and the UAV was operated smoothly and accurately during the simulation flight. This structural design and simulation analysis can provide new ideas for the design of new fire-fighting equipment.
Sports psychology sports science is an emerging discipline,according to the characteristics of soccer and regularity,football teaching and training principle,the theory of sports psychology and college football teaching closely,organize teaching activities,so as to reduce the blindness of teaching,promoting the overall development of students,improve teaching quality.
This paper introduced the salver-shaped insulator which is one of the most important insulating parts in the field of the high-voltage switching device,firstly,the model was designed by the soft of SolidWorks. secondly,in order to analyze the stress of the Salver-shaped insulator,the soft of Ansys Workbench should be applied. Thirdly,when the configuration was up to the mustard,the soft of Ansys should be useful for the electric field computing to check the insulator capability of the model. The last,the Salver-shaped insulator must be checked by the test. The efficiency of design and development of new product will be improved.
Large spaceborne flat seam antennas boom recently. The structure design of the large flat seam antenna is introduced, and finite element model is built. The first frequency of antenna is obtained from modal analysis and it meet the requirement. The results of sine vibration and random vibration shows that strength satisfy the requirement and it has a certain margin.
ABSTRACT: This paper presents a fast fracture propagation prediction method using the XGBoost algorithm, designed to significantly reduce computation time while maintaining high accuracy. By utilizing key parameters such as geomechanical properties, fracturing operation data, and natural fracture distributions, the method efficiently predicts fracture geometry and properties. Latin Hypercube Sampling (LHS) is employed to generate training data, and the model is trained on numerical simulations. Testing on real field cases shows the method predicts fracture geometry with a relative error of 0.6% in length and 1.9% in height for simple fractures, and under 5% for more complex multi-fracture cases. The method's prediction time is proportional to the number of time steps and remains constant regardless of the complexity of the case, requiring only 13 seconds for simple fractures and 85 seconds for more complex ones, compared to traditional simulations that take several minutes or hours. This makes the method highly suitable for real-time hydraulic fracturing operations, providing accurate and timely predictions to support decision-making in complex geological environments. 1. INTRODUCTION Hydraulic fracturing, commonly known as "fracking," is a critical technology for unlocking the vast potential of unconventional reservoirs, such as shale formations. Its importance stems from its ability to access and extract oil and natural gas resources that were previously unreachable. By injecting a high-pressure fluid mixture into rock formations, fractures are induced, creating pathways through which hydrocarbons can flow more easily toward the wellbore for extraction. The geometry of these fractures plays a key role in determining the efficiency of the fracturing operation and directly impacts the production performance of the reservoir (Li et al., 2019; Sun et al., 2021; Liu et al., 2023). Numerical simulations of hydraulic fracturing have become indispensable tools for predicting fracture geometry and understanding the mechanisms driving fracture propagation (Wu et al., 2015). Despite the widespread use of hydraulic fracturing simulations, one of the primary challenges lies in their computational efficiency, particularly in reservoirs with complex geomechanical properties and dense natural fracture networks (Li et al., 2020). These simulations require detailed models of fluid-rock interactions, fracture growth, and stress distribution, and the computational burden grows significantly with increasing geological complexity (Wu et al., 2014). In reservoirs with heterogeneous rock properties or intricate natural fracture systems, traditional simulation methods often struggle to accurately capture fracture behavior. This results in extended simulation times, reduced predictive accuracy, and delayed decision-making during field operations.
Based on theory of water wave and dynamics of Mindlin thick plates, the dynamic behaviors for the steady forced oscillations of a floating elastic plate excited by a localized external load are presented using the Wiener-Hopf technique. Firstly, the results obtained from the present method are compared with the calculations from other methods and those are analyzed. Secondly, the distributions of deflection and the bending moment in plates under three kinds of periodic loadings are investigated. Finally, the relationship among the deflection amplitude distribution of the plate and the central positions and the distribution widths of different periodic loadings are analyzed.
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