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Dong H.,Dalian University of Technology | Zhang X.,Dalian University of Technology | Yang J.,Dalian Shipbuilding Industry Co. | Hu W.,Dalian University of Technology
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2014

Aluminum alloy and brass sheets were lap joined by tungsten insert gas(TIG) arc welding using Zn-15%Al solid-cored filler wire. The mechanical properties of the joint, microstructure in the weld and distribution of major alloying elements in the intermetallic layer were examined. The test results display that the tensile strength of the as-welded joints reaches 164MPa, and that of post-weld heat treated joints is as 160MPa. The analysis results reveal that the dendrites further grow up during post-weld heat treatment, and some dendrites detach from the interface into the weld and worsen the joint performance. The intermetallic layer in the joints mainly consists of CuZn5 phases and grows into weld in the form of columnar crystals.

Cao X.,Dalian University of Technology | Yuan J.,YTO Group Corporation | Li W.,Dalian Yiliya Construction Machinery Co. | Ding C.,Dalian Shipbuilding Industry Co.
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2015

Aiming at the problems of poor precision, low operation efficiency and low security due to the load oscillation of luffing motion for crane, an error asymptotic compensation control method was proposed to minimize the sway angle of load. Based on the analysis of error asymptotic compensation control theory, the error asymptotic compensation controller was designed. Through appropriate adjustments to the two stage compensation coefficients, the sway angle of the lifted load was gradually decreased, meanwhile, the requirements of the acceleration and the pump displacement were met. The MATLAB simulation results show that error asymptotic compensation controller has good robustness and control precision for different ropes and jib lengths. After the crane began to brake, the sway angle is reduced to below 0.003 rad in 10 seconds. ©, 2015, China Mechanical Engineering Magazine Office. All right reserved.

Sun T.,Harbin Engineering University | Zhang Z.Q.,Harbin Engineering University | Sun C.J.,Dalian Shipbuilding Industry Co. | Ma Z.W.,703th Research Institute of China Shipbuilding Industry Corporation
Advanced Materials Research | Year: 2014

The existing fire-extinguishing plants have a lot of problems. For example, the amount of extinguishant is very large, mix is uneven, extinguishant is easy to splash, harmful to the human, the system structure is complex, spray nozzle is demanding and so on. And the open literature sources on the marine fire hydrant are very few. Besides because of the difficulty of numerical simulation of two-phase flow, the research on numerical simulation of the marine fire hydrant is hardly any. In this thesis, a new-style marine fire hydrant is designed to be small volume, easy to use and low pressure lost. It blends the gas to water through its special structure. It regards the gas-water mixture as the extinguishant. In this way, the water flow can be soften, and reduce the splash. The extinguishant can overlay the burnable body uniformly. At last, reach the better extinguishant under the dual effect of the oxygen exclusion and cooling. © (2014) Trans Tech Publications, Switzerland.

Sun T.,Harbin Engineering University | Zhang M.F.,Harbin Engineering University | Sun C.J.,Dalian Shipbuilding Industry Co. | Ma Z.W.,703th Research Institute of China Shipbuilding Industry Corporation
Applied Mechanics and Materials | Year: 2014

Marine gas turbine exhaust ejector device is responsible for reducing or eliminating the infrared signatures of exhaust system. In order to optimize the structure of exhaust ejector and shorten the cycle of research, it is essential to study the successful experiences on exhaust ejectors by scholars abroad. In this article two structure innovations were introduced: the nozzle structure changing from circular to rectangular and multi-stage diffuser, then a new type of marine gas turbine exhaust ejector was designed. Through simplifying the ejector model, numerical simulation was used to predict the characteristics of both the single-stage ejector and the multi-stage ejector. The result indicates the effects of structural parameters on the performance parameters. This research result has certain reference value for marine gas turbine exhaust ejector structure innovations and performance optimization. © (2014) Trans Tech Publications, Switzerland.

Cui J.,Wuhan University of Technology | Li P.,Wuhan University of Technology | Gao F.,Wuhan University of Technology | Bi H.,Dalian Shipbuilding Industry Co.
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2014

On the basis of comprehensive consideration of the practical production process, evaluation indexes are chosen, and two-level fuzzy comprehensive evaluation system is established by applying fuzzy theory. The calculation process of fuzzy comprehensive evaluation is introduced by taking a double bottom block's assembly sequence scheme for specific example, finally the evaluation result of the block assembly sequence scheme is obtained. The evaluation result can provide guidance for practical assembly of ship block.

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