Applied Mechanics and Materials Vols. 148-149

Abstract: That the oil and gas exploration and development is extending into deep water proceeds the rapidly shift to subsea production system. However, complex subsea equipment and frequency offshore accidents aroused the concern on the risk assessment of subsea system. The paper illustrates the hazard aspects which should be focused on in the subsea equipment compared with the surface equipment. The hazards identification and risk analysis on subsea X-tree system is carried out. A general risk-prevent process of subsea X-tree system is illustrated, so does the reliability analysis process. Besides, some commendations on subsea detection and maintenance are presented in the paper.

Abstract: To resolve the complexity and uncertainty between the fault portent and the causes of electric and hydraulic actuator, a fault diagnosis model base on neural network arithmetic for actuator is designed. The genetic optimization arithmetic is used to initialize the value of weight and bias to improve the search efficiency and global convergence of the network. The simulation result indicate the feasibility and validity of the method based on genetic neural network model to diagnose the faults of electric and hydraulic servo actuator.

Abstract: This study describes the manufacturing process of thermal insulating composites which made from fumed silica powder, reinforcing fibre and other additives using advanced mechanofusion technique. The research focuses on the effect and mechanism of Al₂O₃ powder on thermal insulating composites, which using as high temperature shrinkage inhibitors to restrain sintering in fumed silica compacts at high temperatures. The results show that nanosize Al₂O₃ powder can effectively improve the volume stability of the compacts above 800°C, but which has little influence on thermal conductivity at higher temperatures. The compacts prepared in this study exhibit fracture strength of 0.26 MPa at room temperature, thermal conductivity of 0.0336 W/(m•K) at 1000°C and tiny volume shrinkage about 1.1% at 1000°C for 12h.

Abstract: The discovery of buckling instability and vibration of polyethylene/ carbon nanotube matrices is reported by molecular mechanics simulations. The research is aimed to acquire a high strength design of PE-CNT matrix with proper PE/CNT ratio as well as discovering the dynamic characteristics of the PE-CNT composites. The buckling strains and the resonance frequencies are found to decrease with an increase in the number of polyethylene chains in the polyethylene/carbon nanotube matrices. Van der Waals forces are collected to explain the relation of the PE chains to the buckling strain and the resonance frequency of the composites.

Abstract: The requirements of environment monitoring system for solid booster of shipboard missile were analyzed, and the scheme of environment monitoring system based on microcontroller and MEMS sensor was present. The hardware units and typical hardware circuits were given. According to the circuits, the PCB board was designed, and the prototype of environment monitoring system was made and tested. It was shown by the test results the designed system can be used for solid booster environment monitoring.

Abstract: 13 Groups of C20 concrete specimens and 11 groups of C60 concrete specimens adding different content of fly ash and slag powder, comparing with normal concrete specimens, were tested to analyze compressive strength and workability. The test results show: When adding fly ash only, equivalent replacing volume should not exceed 30%, and for lower strength concretes (such as C20) the adding volume should be lower than 30%, otherwise, the compressive strength was influenced greatly. When adding slag powder only, the replacing volume should increase to 40%, meanwhile the workability must be supervised. When adding fly ash and slag powder simultaneously, the adding volume should reach to 50%, and the ratio of fly ash to slag should be controlled. For C20 concrete the ratio of fly ash to slag powder should not exceed 10% and for C60 concrete the ratio should reach to 25%.

Abstract: A novel kind of logging data acquisition is designed based on FPGA.In this paper, the hardware and software are described in detail. Experiment results show that the designed circuit and program are reasonable and reliable by the logging signal simulator, which can meet the logging requirement of oil field.

Abstract: The five rotor models of traditional 850mm, 200*400,200*500,250*500,300*500 and 300*600 were imported into EDEM for dynamic simulation, indicated that the acceleration efficiency of new rotor was better than the traditional. In the new rotor, when the subject rotor radius was the constant, the greater the impact plate installation radius, the better the acceleration efficiency; when the impact plate installation radius was the constant, the greater the subject rotor radius, the better the acceleration efficiency.

Abstract: In view of the complex and error-prone steps when hardware configuration software downloads its engineering files to control templates in a distributed control system, the OneKeyDownload was designed to develop the hardware configuration software, and it was realized by C++. The practice shows that the developments of OneKeyDownload not only simplify the download steps, but also shorten the download time, and it can download the files according to the accurate order by judging the control template is master or slave automatically.

Abstract: With the development and researching more on the ocean, underwater mating technique has been widely used such as ocean workstation, aid submarine lifesaving and military affairs field. In this paper, in order to increase capacity of adapting platform obliquity and adopting rotational skirt scheme, two-joint mating system of underwater vehicle was designed including three-dimension assembly design and control system. It is indicated that the system can meet working space of underwater vehicle passageway and there is not interference phenomenon by assembly design. The finite element of system shell and pressurize of the joint was established. The computing result and pressing test is accordant, thus it is testified that the shell material can meet strength need and joint pressurize is reliable.