Applied Mechanics and Materials Vols. 687-691

Abstract: The supercharged boiler drum level as the controlled object, a high-precision simulation model was established considering the impacts of the distribution of the metal wall condensation inside the drum on the water level changes. Based on simulation model, a simulation program for pressurized boiler was prepared. The simulation results show that the performance of the state fuzzy controller is better than the PID controller.

Abstract: In the deep and ultra deep well casing wear is serious. The decrease of strength leads to casing damage, affects the follow-up well test and completion. In order to analyze the influence of the contact force, rotating speed, steel grade and muds on casing wear, determine the optimized level collocation scheme which makes casing wear minimum, optimize drilling parameters and casing programs, reduce casing wear, four factors and three levels orthogonal experiment of casing wear was carried out, and the range analysis of the experiment results is made. The results show that the best match of factors is A1B1C1D3, namely when the contact force is 200 N(A1), rotating speed 60 r/min (B1), steel grade N80(C1), oil-based mud (D3) casing wear is minimal. The influence of muds on casing wear is the largest, the next is casing steel grade, and then rotating speed, the effect of the contact force minimal. The improvement of mud performance is best method to reduce casing wear.

Abstract: The operation of drilling well leads to casing wear to some degree in cased well. The reduced strength of worn casing threats to the safety of well test and completion. In order to calculate casing wear depth and prevent the casing wear, the wear efficiency and friction coefficient is measured in the different wear time, the contact force and the rotating speed. The wear efficiency increases with the contact force and the rotating speed. And the bigger the rotating speed, the bigger the friction coefficient. The wear efficiency of P110 casing is change from 2 to 8×10-13 1/Pa. The rotating speed has less influence on the wear efficient. So it is reasonable that the wear efficiency model is adopted to calculate the wear degree of P110 casing.

Abstract: The self-propelled winch system was studied taking the 20-ton transitional self-driven winch system as the engineering background. By the analysis of structural characteristics, control loops, speed solutions and hydraulic motor-driven forms of winch hydraulic system, The system of mathematical models was established which lay the foundation of the establishment of system simulation model. The walking hydraulic drive system simulation models were established by using AMESim software. On this basis, by setting different parameters, the simulation system operating conditions are simulated, which verified the rationality and stability of the design of the winch hydraulic transmission system.

Abstract: Heat pipe has excellent conductivity of heat and diversity of structure, so it can be used in machining which can decrease or avoid using the cutting fluid. In this paper, the abrasive tool with rotating heat pipe was designed. To validate that the abrasive tool with heat pipe can safely and steadily grind materials, the model analysis of abrasive tool with heat pipe is carried on with the ANSYS software based on the theory of modal analysis, then the first five order natural frequency and vibration models are to get. The results indicated that the vibrational frequency of designed abrasive tool is far away from natural frequency, so resonance phenomenon does not happen and the abrasive tool with heat pipe can smoothly work.

Abstract: To research the failure mode of solid-web type telescopic jib typical weld, extract and quantify failure characteristics, obtain failure regularity of jib performance and solve the problem that welds do not be established by conventional finite element analysis. The weld strength is replaced by the maximum stress of the corresponding section, which may cause the simulation results low and distortion, and cannot simulate weld defects. A new modeling method is used by this article, which establishes and simplifies the weld physical shape, simulate and analyze weld strength. The Life and Death element technology which is based on the ANSYS software is used to simulate weld defects. The weld strength that is obtained by conventional analysis simulation is 110MPa, after processing, stress of weld model without defects is 395MPa, the theoretical value be calculated is 437MPa, stress of weld model with defect 1, 2, 3 respectively is 586MPa, 402MPa and 475MPa. Through comparing the simulation value and the theoretical value and the comparison between the simulation values, the simplified model that is proved is reasonable, the technical route which is used to simulate weld defect by Life and death element technology is feasible. It can be used to predict failure critical value under typical working condition, assess whether the weld failure. The working condition of jib can be simulated, and the main factors can be retrospect.

Abstract: The failure path of large complex steel structure systems for lattice jib cranes is investigated in this paper. Considering the lack of an explicit function expression in the study of reliability, a method based on a modified response surface method is proposed to quantify the reliability index and the failure probability, capitalizing on the linear-approximated iteration and the difference approach rather than the differential approach in solving nonlinear equations. The major failure path is determined through the analysis of the multiple failure probabilities. The main failure mode of lattice jib cranes is a failure in stability, not a failure in strength based on a comparison of the failure probabilities of both stability failures and strength failures. And the failure path is substantially a rearrangement of the hazardous components and the failure path of components with similar probabilities and close locations varies only in that these components break at distinct starting positions. Finally a proposal is put forward to heighten in engineer practices the security reserves of hazardous components to achieve high reliability of an overall system.

Abstract: Based on the theoretical analysis on the coupled vehicle-bridge vibration, this paper simulates the action of the moving vehicle load on a bridge structure with a sprung mass model, and obtains the dynamic response of the simply-supported bridge structure under the moving vehicle load through computation by finite element method (FEM). Through checking computations of classic examples, this paper proves the applicability of this computation method.

Abstract: As for the characteristics of strong nonlinearity and model uncertainty of gas internal combustion generator, an additional throttle controller based on extended state observer (ESO) and terminal sliding mode control is proposed in this paper on the basis of gas internal combustion generator’s main speed controller. After tracking the system states and uncertainty in the system mode as well as the external disturbance by using extended state observer, additional throttle controller is designed on the basis of terminal sliding mode control theory. The simulation result of an one machine-infinity bus system shows that the controller has good control effect and robustness, which will effectively improve the performance of gas internal combustion generator speed control system.

Abstract: In this paper, a method of the UAV path planing in the complex environment by using artificial potential field and differential game theory is introduced. This article studies the pursuit evasion game of the dynamic path planing for the UAV. The fly zone of either the pursuer or the evader is divided into two categories, namely the obstacle areas and the obstacle-free areas. So we can use the artificial potential field in the obstacle areas,and we use differential game theory in the obstacle-free areas for the UAV. This method can apply to pursuit-evasion game in the complex environment for the UAV path planing.Not only the UAV can avoid obstacles but also they can find the best capture path.Finally,the simulation results verify its correctness and validity .