Applied Mechanics and Materials Vols. 651-653

Abstract: Full face rock tunnel boring machine in construction process, disc cutter put pressure on rock breaking, actually belongs to the process of energy transfer, from the point of view of energy analysis the energy transfer rules in the process of disc cutter rock breaking, based on CSM force prediction model, analysis disc cutter energy input and rock mass energy output efficiency ratio, for excavation with minimum energy efficiency. Taking S-536 Hong Kong water tunnel TBM as an example, When the penetration is 10mm, based on the energy efficiency ratio the optimal disc cutter spacing should be less than 70mm, than the actual average disc cutter spacing is small 2mm, rock mass as a reference the disc cutter rock breaking efficiency mechanism provides certain reference value for the cutter layout.

Abstract: In order to verify that the +20m platform hoist for Qinshan Nuclear Power Plant can withstand safe shutdown earthquake (SSE) without any damage, that is during or after SSE, completeness of structure and operation can be ensured, finite element analysis software, ANSYS Workbench is applied to analysis on model building and seismic analysis for the platform hoist (including hoisting mechanism, base plate,drum).

Abstract: In this paper, a method based on Ziegler Nichols - frequency response of the adaptive PID controller is proposed. The control circuit online identify important critical frequency response characteristics of process object through input and output data in the normal process operation, and then the system online update PID controller parameters based on Ziegler - Nichols tuning rules or by the improved method. The adaptive process of PID controller does not require any prior knowledge of the system, but it can always guarantee control circuit run in the best condition . The results show that the method has stronger robustness and adaptive ability.

Abstract: In this paper, we propose a novel and efficient flash translation layer scheme called BLTF: Block Link-Table FTL. In this proposed scheme, all blocks can be used for servicing update requests, so updates operation can be performed on any of the physical blocks, through uniting log blocks and physical blocks, it can avoid uneven erasing and low block utilization. The invalid blocks, in BLTF scheme, could be reclaimed properly and intensively, it can avoid merging log blocks with physical blocks. At last, the BLTF is tested by simulation, which demonstrates the BLTF can effectively solve data storage problems. Through comparison with other algorithms, we can know that the proposed BLTF greatly prolongs service life of flash devices and improves efficiency of blocks erasing operation.

Abstract: Flexible pipes, which can be divided into bonded and unbonded types, have been used for years in the oil industry. An unbonded structure presents a large interest in offshore production as they allow to realize simple liaison between the seafloor and the surface. In the present paper, an unbonded flexible pipe under axial force has been analyzed by finite element (FE) method in which eight layers of the unbonded flexible pipe have established. Solid and shell elements are used to simulate the layers. In the FE model, all layers are modeled separately with contact and friction interfaces between each layer. The numerical results are compared to the literature’s results, which shows very good agreement with numerical and other existing results, have validated the use of the given model. It might provide practical and technical support for the application of flexible steel pipes.

Abstract: Negative plate forming is one of the important tasks of silver-zinc battery production. The objective of this work is to develop an automated forming system of negative plates to ensure the workers’ health and safety and to improve its production efficiency. The ointment injection and layer press method was studied by using two 3DOF robots moving and injecting zinc ointment along required trajectory and four 1DOF robots carrying the molds, carrier papers and metal grids between transportation lines and other machines. Experiment results show that the developed system with optimized parameters can reach the requirements of processing quality.

Abstract: Working principle and advantages of tube in hydroforming with radical crushing were described and introduced briefly. The research status of deformation behaviors of tube in hydroforming with radical crushing with the tube cross-section shape was made into triangle, rectangle or trapezoid were reviewed in this paper. Finally, the development trend and burning questions of tube in hydroforming with radical crushing were predicted.

Abstract: In order to address and meet the needs of people in these regions without electricity, we designed a small 500W off-grid PV-inverter. The main circuit includes battery charge and discharge circuit, and two-stage converter topology isolated. The digital processor TMS320F28023, high-performance and low-cost, is used to achieve maximum power point tracking (MPPT) of PV modules and charge control for battery. The experimental results of the prototype show that this design with high-precision and high-efficiency, meets the design requirements.

Abstract: In this paper, a method to design coupling and filtering device for low-voltage power line communication system is presented. The data transfer mode of power line communication and the signal’s working attenuation of low-voltage power line are analyzed. As for low-voltage power line, the input impendance is stable in the frequency band over 1MHz. So the working band of the coupling device is 4MHz-21MHz. Based on capacitive coupling, we use coupling capacitance as the main element and design a coupling circuit. Filters are needed when the coupling device is receiving a signal. Based on Chebyshev filter, we design a band-pass filter and make a simulation.

Abstract: power quality problems such as high line loss, low voltage exist commonly in rural power grid of China due to few supply points, long power transmission and distribution line. Huge fund is required to increase the quantity of supply points in rural power grid; installation of var compensators on line nodes could not solve power quality problems on the whole line. At the same time, as distributed power supply, wind power is also restricted by peak regulation, insufficient line output capacity and other factors in large scale centralized grid-connected output, wind curtailment often occurs. In order to solve the above-mentioned two problems simultaneously, electric power of wind farm may be output via nearby rural power grid line, thus not only utilization rate of wind power is increased, but also power quality of rural power grid is improved.This paper takes an example of a district in Fuxin City, summarizes power quality change data of relevant rural power grid before and after the distributed grid connection of wind farm is made, the analysis shows that distributed grid connection of wind power could improve load flow distribution of the power system, reduce system transmission loss in this district obviously, increase economical efficiency of the system operation effectively. At the same time, effectiveness of static var generator in substation to overcome the impact of such grid connection mode on power grid is verified.