Applied Mechanics and Materials Vols. 256-259

Abstract: The Ship-Bridge collision accident risk evaluation model based on the analytic hierarchy process (AHP) was established and the weights of factors were confirmed. Qualitative and quantitative assessments of the Vessel-Bridge collision accident risk level were accomplished. The application results show that the possibility of Ship-Bridge collision accident could be evaluated by the security risk evaluation model based on the AHP. It can provide decision-making suggestions for the sitting of the new bridge and optimal evaluation for bridge type scheme.

Abstract: Effective monitoring of worker is one of the crucial elements in accident prevention. With advancement of sensor technologies, real-time tracking research has been conducted for improving effectiveness of monitoring in safety management. However, most of previous studies were limited to outside construction work which normally indicates excavation and heavy equipment operation. This study proposes automatic worker location tracking and risk alert system for effective risk recognition and worker monitoring that integrates smartphone and Building Information Model (BIM). A prototype system has been developed and tested based on small room. The test results show that the system has the potential to reduce labor and time for monitoring and improve the recognition of fall accident risk on the job site in real-time.

Abstract: The subway tunnel benchmodel(1/3)of small scaled size is established to study fire spread control effect under the combined effect of the longitudinal smoke discharge and water mist. The different working pressure of water mist is opened at the same time with the smoke discharge. The suppression effect of the diesel pool fire is observed and it can be concluded as follows: When the longitudinal smoke is started, it can effectively control the spread of smoke, but the lasted combustion time of fire increased, the sole longitudinal smoke discharge is not the optimum measurement on the control of diesel pool fire. For the diesel pool fire with the surface size of 250mm×200mm, the experiments show that the combination of water mist and longitudinal smoke discharge, which were started simultaneously, are able to control the fire effectively. And the 15MPa water mist is the best on the fire control affection with the combination of smoke discharge.

Abstract: Smoke control for the underground platform of a high-speed railway station was investigated. Nowadays, the development of high-speed railway in China is rapid. In order to economize valuable urban space and to realize the convenient interchange to the subway, some of the high-speed railway station platforms and transfer halls are set underground. It is difficult and uneconomic to achieve static ventilation in the underground platform. Therefore, The mechanical smoke control system is the most feasible and most reliable method to ensure the fire safety of the underground platform. How to protect the evacuation stairs free from the threat of fire-induced smoke is a major concern of smoke control in the underground platform. An underground island platform and underground waiting and transfer halls of an under construct high-speed railway station in south China are reconstructed in this paper. Three smoke control modes based on mechanical ventilation, namely mechanical air makeup, pressurized air supply for stairwell and air curtain, are numerically simulated by Computational Fluid Dynamics (CFD) method. The distribution of smoke, temperature, and CO in the platform and influences of them on evacuation staircases are computed and analyzed. The effect of fire location in smoke spread are explored in our research. This study based on CFD modeling enables the improvement of the design and operation of smoke control and exhaust system for underground high-speed railway station. The results are applicable to practical fire engineering designs for underground high-speed railway station platform.

Abstract: Optimization method was designed via selecting a series of self calling functions on the basis of application of recursive algorithm method. An optimization method for unifying section of transmission tower’s chord member was testified from the example. The procedure to the feasible combination patterns for unifying section was put forward by recursion. Based on the hypothesis of static determination, the sections of the members in each pattern were shown, and the optimal design can be obtained by comparing existing patterns. Three different constraint inputs of transmission tower were checked by the recursion algorithm method in this paper. The comparison result shows that the design of unifying section save 123 Kg of steel after optimization under the condition of 5 division pattern of chord member. The number of possible combination of unifying section pattern was increased sharply, while the optimal weight of tower is decreased with the division of chord member.

Abstract: Differential power analysis (DPA) attack is an important threat that researchers spend great effort to make crypto algorithms resistant against DPA attacks. In order to determine whether the hardware has DPA leakage before manufacturing, an accurate power model in digital simulation has been generated. FPGAs Arrays are attractive options for hardware implementation of encryption algorithms. In this paper, we show generated power model by using integer numbers whole DES’s rounds vs. S-Box alone, and this method gives more realistic results to determine the effectiveness of the improvements protect whole DES rather than in which only informer elements in the DES round. In particular this allows the user to isolate some parts of its implementation in order to analyze information leakages directly linked to them. We review s-box because it’s get 2kbit or 20% CLB slice from FPGA to implement DES or TDES. This paper try to identify role of Sbox in DPA.

Abstract: Air reverse circulation (RC) drilling is becoming an increasingly popular technique in engineering fields. It can be used in geological exploration, water well drilling and infrastructure construction and so on. RC bit is the key accessory in this technique. Its structural parameters directly influence cutting transportation during reverse circulation drilling. In order to explain the formation mechanism of reverse circulation, established mathematical models and physics model of the RC bit and studied drilling fluids transportation under the bottom hole. Conducded numerical simulation about velocity field and pressure field of bottom hole flow field using software FLUENT with different parameters of the RC bit, including the size and position of nozzles, the angle of inner nozzle and so on. The result of simulation and experiment show that increase of the effective turbulence zone can improve efficiency of RC transportation. Inner nozzles can produce stable negative pressure region in the central channel, and ensure cutting transportation as RC methods. The data and results are helpful to optimize the structure and size of the RC bit. It can shorten the research period, decrease costs and improve the design ability.

Abstract: Close framework structure becomes recently a competitive solution for taxiway bridges. Due to no pile foundation construction, it has short duration and significant economic benefits. The development of close framework CAD system adopts Visual Basic and bases on secondary development interface in AutoCAD VBA to draw construction plans, such as structure diagram, bridge layout, prestressed tendons and ordinary reinforced chart. Another feature is the automatic generation of materials amount Excel tables and model for finite element analysis. The main program code of graphic object realization and deign parameters import are described. For the unique professional characteristic in airport project, the software system has a considerable engineering prospect.

Abstract: The expanded diameter conductors are widely used for high voltage electricity power transmission due to its superior ability to prevent electronic corona phenomenon. However an undesired stability problem of wire distribution configuration within the cross-section of the conductor often occurs during the power line stringing processes, especially for the not-well-designed conductor structures. This phenomenon is typically characterized by the appearance of outer wire/wires jumping out of the layer; therefore it is also referred as wire jump-out problem. Finite element model which can predict the wire jump-out phenomenon has been successfully developed in this research project. Series of stimulations have been carried out to investigate the key factors to cause the wire jump-out problem. The reduction of radial distances between the adjacent aluminum wire layers due to the obvious indentation deformation at the trellis contact points were identified to be one of the most significant factors to lead to the wire jump-out problem. Numerical results show that keeping sufficient initial gap between the adjacent outer layer wires in the initial design can be a simple effective way to relieve/avoid the wire jump-out problem.

Abstract: At present, the torpedo shell analysis includes fluid analysis and structural analysis. The fluid pressure distribution of torpedo surface is the results of the fluid analysis, and it is the outer load input of torpedo shell analysis. Meanwhile the results of torpedo shell structure analysis also play a important role in binding. So torpedo shell structure analysis is a fluid-structure interaction analysis. With the development of engineering analysis software, Fluid analysis software Fluent and structural analysis software ANSYS are able to analyze torpedo fluid and structural. But there has not been a specialized software to handle fluid-structure interaction analysis. This paper coupled Fluent and ANSYS, and got an analysis method for torpedo shell fluid-structure interaction analysis base on Fluent and ANSYS