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18 December 2012, Volume 32 Issue 6 Previous Issue    Next Issue

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Review of Research of  Blast Impact of Sandwich Structures XIAO Feng,CHEN Yong,ZHANG Zhen-hua,ZHU Da-wei,HUA Hong-xin 2012, 32(6): 1-7.  DOI: 10.3969/j.issn.1006-1335.2012.06.001 Abstract ( )   In order to understand the protection performance of sandwich structures against explosion shock, domestic and international researches of dynamic responses of sandwich structures under impulsive blast were reviewed. At first, the?sandwich?constituents, core configurations and materials were introduced. Then, the review was focused on three?aspects, namely analytical model, numerical simulation and experimental investigation. Finally, the methods and contents of the researches were summarized, and?the?future trend of the research was predicted. Related Articles | Metrics

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Review of Structural Modeling Methods for Bolted Joints SUN Dan，LI Wan-you，LV Bing-lin 2012, 32(6): 8-12.  DOI: 10.3969/j.issn.1006-1335.2012.06.002 Abstract ( )   PDF   The domestic and international research methods for static and dynamic analyses of bolted joint structures were summarized. The research status, advantages and disadvantages of different numerical models and theoretical models from simple static analysis to complex nonlinear dynamic analysis were reviewed. Finally, it was pointed out that establishment of all-purpose models for structural analysis of bolted joints combining with engineering projects might become a hot research concentration in the future. Related Articles | Metrics

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Analysis of Shock Injury of Ship Personnel due to Underwater and Air Explosion HUANG Jian-song,WANG Yu 2012, 32(6): 13-16.  DOI: 10.3969/j.issn.1006-1335.2012.06.003 Abstract ( )   PDF   In modern naval wars, the ships may be attacked by air or underwater explosive weapons, which not only damage the ship structures, instruments and weapon systems, but also seriously injure the crew on shipboard. In this paper, the refined description, comparison and analysis on ship shock injury, air shock injury and underwater shock injury were given respectively in several aspects, including shock wave characters, injury mechanisms, injury symptoms, safety limits and protection measures. Results of the research will be helpful to precisely and fast diagnose and cure the wounded, as well as offer a reference for anti-shock protection research. Related Articles | Metrics

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Dynamic Responses of Three Kinds of Ship Alloy Steels ZHAO Peng-duo,DU Jian-ye,ZHANG Lei 2012, 32(6): 17-20.  DOI: 10.3969/j.issn.1006-1335.2012.06.004 Abstract ( )   PDF   The dynamic compression properties of three kinds of alloy steels (material A,  B and C) were tested with the split Hopkinson pressure bar (SHPB) in the range of strain rate 500 s-1～7 500 s-1 respectively. The experimental results show that the yield stress of material A is the largest, and that of material B is the smallest.  The strain rate effects of both materials A and B are not obvious in the range of strain rate 500 s-1～6 000 s-1,  and weak strain rate effects appear in the range of strain rate 6 000 s-1～7 500 s-1.  The dynamic stress-strain curves of both materials A and B have strain hardening phenomena. The strain rate effect of material C is not obvious in the range of strain rate 500 s-1～7 500 s-1,  but the strain hardening phenomenon is remarkable. Related Articles | Metrics

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Analysis of Temperature Feature for Pipeline of Novel Dual-wave Shock Test Machine WEN Zhao-dong,ZHANG Lei,SHI Shao-hua 2012, 32(6): 20-22.  DOI: 10.3969/j.issn.1006-1335.2012.06.005 Abstract ( )   PDF   A finite element model for pipelines of novel dual-wave shock testing machine was built by means of FLUENT code. The flow field and the temperature field of the pipelines in different status were analyzed. Simulation results show that the temperature of the pipelines rises about 3°C in operation status, which will not affect the use of the dual-wave shock testing machine. Related Articles | Metrics

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Security Analysis for Floating Shock Platform Test Subjected to Underwater Explosion YANG Li，DU Jian-ye，DU Zhi-peng，WEN Zhao-dong 2012, 32(6): 23-25.  DOI: 10.3969/j.issn.1006-1335.2012.06.006 Abstract ( )   PDF   Security of the floating shock platform test was studied with theoretical analysis and simulation. The safety radius of ship and persons in the water area, the safety distance of typical shore-based buildings, and the ideal safety radius of testing area and depth of the water area were given. This study may?provide a reference for floating shock platform test. Related Articles | Metrics

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Analysis of Shock Response of Small-sized Floating Platform in Underwater Explosion JIANG Guo-yan,SONG Jing-li,ZHOU Hua,JIN Hu 2012, 32(6): 26-29.  DOI: 10.3969/j.issn.1006-1335.2012.06.007 Abstract ( )   PDF   Floating shock platform is an important tool in the assessment of equipment’s shock resistance abilities of large and medium-sized shipboards. Many navy-powerful countries pay great attention to shipboard’s equipment shock test research. Using wavelet analysis method, the measured signal of a small floating platform was processed and analyzed in this paper. The results indicate that the impact response of the small floating platform is mainly high frequency vibration due to shock waves. With the vibration propagating in structures, the energy decays gradually. The equipment’s buffer device can rapidly attenuate the energy induced by high frequency vibration, and can effectively protect the equipment from high-frequency vibration impact. Related Articles | Metrics

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Analysis of Shock Response of Small-sized Floating Platform in Underwater Explosion CHEN Jian-jun，ZHANG Shu-hong,MAO Qiu-dan,JIN Hui 2012, 32(6): 30-33.  DOI: 10.3969/j.issn.1006-1335.2012.06.008 Abstract ( )   PDF   Floating shock platform is an important tool in the assessment of equipment’s shock resistance abilities of large and medium-sized shipboards. Many navy-powerful countries pay great attention to shipboard’s equipment shock test research. Using wavelet analysis method, the measured signal of a small floating platform was processed and analyzed in this paper. The results indicate that the impact response of the small floating platform is mainly high frequency vibration due to shock waves. With the vibration propagating in structures, the energy decays gradually. The equipment’s buffer device can rapidly attenuate the energy induced by high frequency vibration, and can effectively protect the equipment from high-frequency vibration impact. Related Articles | Metrics

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Shock Response Computation of Vibration-isolating System of Marine Floating Raft Using DDAM LI Xiao-ming,CHEN Feng 2012, 32(6): 34-39.  DOI: 10.3969/j.issn.1006-1335.2012.06.009 Abstract ( )   PDF   Methods of shock-resistance analysis and anti-shock design of onboard equipments were discussed. The Dynamic Design Analysis Method (DDAM) of U.S Navy was reviewed in detail. Using ANSYS code, the model of a vibration isolating system of marine floating raft was established, and the vibration modes were computed and analyzed. By writing programs, the natural frequency of the model was calculated. It was found that the natural frequencies of the first 12 orders were in accordance with those resulted from ANSYS code. Thus, the model can be considered to be practical in global stiffness and mass distribution. Furthermore, the shock response of the vibration isolating system of the marine floating raft was calculated and analyzed based on U. S. Naval rule DDS 100-7. This work may be helpful for analyzing the shock-resistant performance of naval onboard equipments. Related Articles | Metrics

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Shock Resistant Effect Simulation of Accumulator in  Hydraulic Rudder System of Ships DONG Ren-yi,WU Chong-jian,ZHANG Jing-wei,PENG Wen-bo 2012, 32(6): 40-43.  DOI: 10.3969/j.issn.1006-1335.2012.06.010 Abstract ( )   PDF   The multi-field unified modeling tool MWorks based on the Modelica language was introduced. Types of the accumulator mathematical model, the basic model applied in this tool, were summarized. The basic model and improved model of accumulator used in the simulation were provided. And the time parameter ? applied in these models were discussed. The accumulation model was then added to the conventional simulation model of hydraulic rudder system of ships as a new model. The inlet and outlet pressures of the selector valve computed with the two models were provided and compared. The simulation results indicate that the accumulator has a shock-resistant effect on the hydraulic system，it can drop the peak values of the valve port pressure considerably as the system reversing. Related Articles | Metrics

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Whipping Response of Slender Cylindrical Shell to  Underwater Explosion WANG Hai-kun,LIU Jian-hu,PAN Jian-qiang,WANG Jun,MAO Hai-bin,ZHANG Lun-ping 2012, 32(6): 44-48.  DOI: 10.3969/j.issn.1006-1335.2012.06.011 Abstract ( )   PDF   The whipping response of slender cylindrical shell subjected to underwater explosion is investigated in this paper. The double asymptotic approximation method (DAA) is employed to describe the coupling effect of the dynamic distortions of the structure and the transient fluid field, and model experiments are implemented to validate the method. The whipping response characteristic of slender cylindrical shell to underwater explosion are researched in different test cases, and the research results may be helpful to understand the underwater explosion induced dynamic behavior of underwater structure. Related Articles | Metrics

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Study on Shock Environment Characteristics for High-impact Medium-weighted Shock Machine HE Bin,TANG Jia-wei 2012, 32(6): 49-53.  DOI: 10.3969/j.issn.1006-1335.2012.06.012 Abstract ( )   PDF   High-Impact medium-weighted shock machine is one of the standard check-up facilities prescribed in GJB150.18-1986. It is used to mainly assess the anti-shock ability of the ship’s equipment whose mass is from 120 kg to 2 700 kg. Based on a large number of shock environment tests for medium-weighted shock machines, the standard check-up conditions for MIL-S-901 machines were worked out in the United States. Our medium-weighted shock machines were designed after American design standard, and the check-up standard was also specified following American standard. But we have not yet known clearly the feature of the shock environment of shock machines, the influencing factors of shock environment and the problems in the current standard in our country. Therefore, aiming at the requirements in the shock environment of shock machines, some suggestions for improvement of the standard for anti-shock check-up of ship’s equipments were proposed. Related Articles | Metrics

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Dynamic Invalidation Criterion of Metallic Material during  Underwater Exploison ZHANG Lun-ping,YAN Bo,PAN Jian-qiang,LIU Jian-hu,ZHOU Zhang-tao,HAO Yi 2012, 32(6): 54-57.  DOI: 10.3969/j.issn.1006-1335.2012.06.013 Abstract ( )   PDF   Underwater explosion experiments were made for cylinder models. Based on the experiment data and energy method, they found the dynamic fracture strain and dUnderwater explosion experiments were conducted for cylinder models made of metallic materials. Based on the experimental data and energy method, the dynamic fracture strain and dynamic yield stress during near underwater explosion were obtained. By comparing the data of the underwater explosion experiments with that of the statics experiments and the SHTB experiments, the difference of yield stress, maximum tensile strain, energy absorbing density, etc. were analyzed. Finally, the applicability of the invalidation criterion from SHTB experiments for underwater explosion was discussed. Failure criterion of the metallic material resulted from the conventional method was compared with the result of actual underwater explosion test. This work is helpful for anti-explosion design and evaluation of ship/model structures.ynamic yield stress during near underwater explosion. By comparing underwater explosion experiments with static experiments and SHTB experiments, the difference of yield stress, maximum tension strain and energy absorbing density .etc were analyzed. At the end, they dissussed the applicability of the invalidation criterion from SHTB experiments for underwater explosion.The paper innovatively compared the general method and the actual underwater explosion effect about the metal material,which is helpful for ship (model) structure anti-explosion design and evaluation. Related Articles | Metrics

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Shock Response Analysis of Typical Contact Surface YanYAN Bo,WANG Hai-kun,HE Bin Bo 2012, 32(6): 58-61.  DOI: 10.3969/j.issn.1006-1335.2012.06.014 Abstract ( )   PDF   There are many contact surfaces in shipping equipments, whose dynamic transmission characters is the key of its computation of response under shock loadiThere are many contact surfaces in ship’s equipments, whose dynamic transmission performance is the key in computation of equipment’s response under shock loading. In this article, the dynamic response of equipment with typical contact surfaces under shock loading was researched numerically and experimentally. The dynamic characters of the contact surface and the transmission characters of shock loading in the contact surface were also discussed. The research shows that the stiffness of the contact surface varies non-linearly during the shock process and the distribution of the acceleration is affected by the contact surface. The comparison between the experimental and computation results shows that the numerical method used in this article has engineering accuracy.ng. The dynamic response of an equipment with typical contact surface under shock loading is researched in this article. The dynamic characters of the contact surface and transmission characters of shock loading along the contact surface are also discussed. The research shows that the stiffness of the contact surface varies non-linearly during the shock process and the distribution of the acceleration is affected by the contact surface. The comparison between the excremental and computing results shows that the numerical computing method used in this article has engineering accuracy. Related Articles | Metrics

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Computation and Analysis of Shock Characteristics of Elastically Supported Gearbox in Time Domain DAI Guang-hao,GAO Chang-wei,LIU Yong-heng,ZHANG Fan 2012, 32(6): 62-65.  DOI: 10.3969/j.issn.1006-1335.2012.06.015 Abstract ( )   PDF   The finite element model of an elastically supported gearbox was established by means of ABAQUS code. Its equivalent shock load spectrum was confirmed in virtue of Federation Wehrmacht vessel construction standard BV0430/85 of Germany. This load spectrum was then converted into equivalent double-triangular wave acceleration shock load and input into the finite element model. The time-domain response characteristics of the elastically supported gearbox with and without limiters were numerically simulated under the shock load respectively. The corresponding acceleration, velocity and displacement response curves of the gearbox were obtained, and the effects of the limiters of the gearbox on its anti-shock performance were analyzed. This work has some guiding significance for the shock-resistance design of elastically supported gearboxes. Related Articles | Metrics

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Performance Analysis of Six-rod Shock-isolation Mount DING Wei,GUO Yun-song,LI Jia 2012, 32(6): 66-69.  DOI: 10.3969/j.issn.1006-1335.2012.06.016 Abstract ( )   PDF   A mechanical model of a six-rod shock-isolation mount with different crash-constraints was established. The dynamic characteristics of the shock-isolator were studied. A shock test was then carried out for the six-rod shock-isolation mount. The shock response and several key points for design of the six-rod shock-isolation mount were summarized through the comparison between theoretical and experimental results. Related Articles | Metrics

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Ultimate Shock Load of KA Bending Rubber Vibration Isolator ZHOU Xiang-rong,LI Jia,FENG Hai-jun,GUAN Yue-ying 2012, 32(6): 70-73.  DOI: 10.3969/j.issn.1006-1335.2012.06.017 Abstract ( )   PDF   The ultimate shock load of KA-100 bending rubber vibration isolator was investigated experimentally. In addition, numerical simulation was carried out to simulate the anti-shock performance of the isolator. Using the Yeoh hyperelastic model, viscodamping method and ABAQUS code, the ultimate shock load of the isolator was analyzed considering geometrical non-linearity effect. Good agreement between the numerical results and experimental results proves the efficiency of the numerical method. Related Articles | Metrics

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Research of Testing Equipment Buffering Technology and Platform GUO Yun-song,ZHANG Xin-wei,LI Jia,ZHOU Xiang-rong 2012, 32(6): 74-77.  DOI: 10.3969/j.issn.1006-1335.2012.06.018 Abstract ( )   PDF   Testing equipment buffering platform can provide a reliable working environment for testing equipment, and offer an impact protection, stable power supply and sufficient operating space in the progress of impact test. Buffering platform is an elastic platform supported by FD40-10 air springs and polyurethane damper blocks. The platform was fitted out an isolation transformer and a high-power uninterrupted power supply according to the requirement of ship’s electrical power system. Based on theoretical analysis, laboratory test and practical equipment impact test, it is demonstrated that testing equipment buffering platform is necessary for reliably acquiring testing data during the impact test. Related Articles | Metrics

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Shock Response Analysis of Axially-bolted Connection HE Hua,LI Jia,BI Cheng 2012, 32(6): 78-80.  DOI: 10.3969/j.issn.1006-1335.2012.06.019 Abstract ( )   PDF   A finite element model of the axially-loaded bolts was established to investigate their shock response characteristics. The test clamps for suspending and horizontally mounted bolts were manufactured. Data groups of acceleration response were obtained through the shock experiment. The acceleration and stress responses of the bolt connections were surveyed through the explicit dynamic analysis. Mutual comparison of simulation results and experimental results has verified the reliability of the application of the FEM method. Related Articles | Metrics

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Numerical Simulation and Reliability Analysis of Cylinders of Marine Steam Turbine under Impact of Broken Blades TAN Hai-Tao,LI Hong-gang,YU Yong-feng,SHANG Chao 2012, 32(6): 81-84.  DOI: 10.3969/j.issn.1006-1335.2012.06.020 Abstract ( )   PDF   A numerical model of a cylinder of marine steam turbine was established for analyzing its reliability under the impact of fractured blades. In this model, the initial speed, mass, yield strength, modulus of elasticity of the fractured blades, as well as the elastic modulus, yield strength and ultimate strength of the cylinder material were taken as random variables. A certain number of samples were acquired using Monte Carlo method. The distribution of random variables was obtained via curve-fitting using a few samples among them. Then, 50 groups of initial values of random variables were obtained using the program for generating random variables, and the process of penetration of the cylinder was simulated with this model. The maximum equivalent stress of the cylinder was obtained. Adopting the ultimate strength criteria and W-testing, the maximum equivalent stress of the cylinder was validated to obey the normal distribution, and the destructive probability of the cylinder was obtained. A reliability analyi Related Articles | Metrics

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Fast Damage Evaluation of Naval Vessel under Air Explosion HU Yu-tao,JIANG Bang-hai,LU Fang-yun,ZHANG Duo 2012, 32(6): 85-87.  DOI: 10.3969/j.issn.1006-1335.2012.06.021 Abstract ( )   PDF   In order to fast evaluate the damage of naval vessel under air explosion, a simulation model was developed. By analyzing the relative location of warhead and the naval vessel and using empirical formula of blast wave, the peak pressure on the vessel under air blast loading was calculated. By simulating the fragment fields and using the THOR model, damage caused by the fragments was calculated. Compiling this visual simulation by Visual C++ and glut database, the 3D scene roaming was realized, and the image of damage was obtained. Related Articles | Metrics

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Hull Box Girder Design and Analysis of Its Antiknock Performance GUO Jun,WANG Jun,DING Jian-jun,CUI Jie,SUN Feng 2012, 32(6): 88-93.  DOI: 10.3969/j.issn.1006-1335.2012.06.022 Abstract ( )   PDF   Applying the hull box girder can improve the longitudinal strength of the structure. The box structure can protect important pipelines and cables in the girder and speed the construction. And it is also beneficial for quality control of construction and easy maintenance of the structure. However, currently the box beam structure is only used in local structures instead of the entire ship. In this article, taking a conventional hull as the base, the box girder was used for the whole ship design in order to improve the ship’s antiknock performance and meet the requirements of vitality. The hull structure was built by a steel box girder to bear the global loading. The hull shape lines and their necessary local stiffness were guaranteed by the light-weight and high-strength composite sheets. Thus, decoupling of local strength and global strength of the hull could be realized in this way. Based on the acoustic coupling method, the response of the hull to explosion was analyzed by means of ABAQUS software. And it as confirmed that the box beam structure has a better antiknock performance. Finally, the design of the hull box girder was optimized for further improvement of the antiknock capacity of the hull. Related Articles | Metrics

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Dynamic Response of Ship’s Double Bottom Tanks Subject to   Underwater Explosion GUO Jun,CUI Jie,XIAO Wei,SUN Fen,LI Shi-ming 2012, 32(6): 94-99.  DOI: 10.3969/j.issn.1006-1335.2012.06.023 Abstract ( )   PDF   The loading characteristics of ship’s double bottom tanks subjected to underwater non-contact and contact explosions were researched respectively using AUTODYN finite element software. The loading type of the double bottom tanks during semi-load and full load conditions was analyzed, and the influence of explosive distance and loading condition on the loading characteristics of internal plate was discussed. The result showed that the transmitted shock wave is the major threat of the inner plate in full-load condition; the splashing loading is the major threat of the inner plate in semi-load and non-contact situation; and high-velocity water-jet is the major threat of the inner plate in semi-load and contact situation. Therefore, the semi-load condition of double bottom tanks is strongly recommended to warship in active time. Related Articles | Metrics

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Research of Anti-shock Layer and Innovation Design ZHANG Zhen-hua 1, CHEN Yong 1, HUA Hong-xing 1, WANG Yu 2, XIAO Feng 1 2012, 32(6): 100-104.  DOI: 10.3969/j.issn.1006-1335.2013.01.024 Abstract ( )   PDF   The dynamic crush behavior of an anti-shock layer with elastic foundation was investigated. Considering the hyperelastic and viscoelastic behavior of the material, the shock resistance capacity of the anti-shock layer was analyzed. Influence of the structure parameters, such as relative density, edge length and topological shape, on the anti-shock performance of the layer was studied. It was found that in low frequency range the shock spectrum is lower when the relative density and the edge length of the layer are smaller, and round hole is the best choice for the anti-shock layer. While in high and middle frequency range, the anti-symmetric honeycomb structures have the best dynamic performance. On the base of the analysis, the optimization design, called anti-shock double-layer structure, has been provided, which has excellent dynamic performance compared to the traditional anti-shock layer. Related Articles | Metrics

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Shock and Buffer Experiment of a Non-Newtonian Fluid Damper and Its Modeling Simulation SUN Jing-ya 1, JIAO Su-juan 1, WEN Zhao-dong 2, HUA Hong-xing 1 2012, 32(6): 105-107.  DOI: 10.3969/j.issn.1006-1335.2012.06.025 Abstract ( )   PDF   Shock and buffer experiment of a non-Newtonian fluid damper was carried out.  A mathematical model to simulate impacting and buffering process of the damper was built. The corresponding parameters in the model, such as factors of the impact system, damping factor and velocity exponent of the damper, were obtained based on the experiment results. It was found that this kind of anti-shock damper is different from the traditional fluid damper in design. The impact parameters of the anti-shock damper have large influence on the maximum impact force and the width of the shock impulse, which should be considered in the design. Moreover, in the buffering process, the damping force decreases quasi-linearly with time, which shows that the damper has a good performance in energy absorbing. Research in this paper can be used as a reference for the design of anti-shock damper. Related Articles | Metrics

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A New Algorithm for Collision Force between Skin-to-skin Connected Vessels during Replenishment JIANG Feng,FENG Qi 2012, 32(6): 108-110.  DOI: 10.3969/j.issn.1006-1335.2012.06.026 Abstract ( )   PDF   The collision between the vessels during skin-to-skin connected replenishment was modeled based on the multibody dynamics with unilateral contacts and classical marine hydrodynamics. With additional water mass taken into account the collision force expression was deduced for the vessels without anti-impact protection device, and relevant numerical simulation was presented. In order to improve the efficiency, during simulation process the identification of practical constraints for non-smooth system was converted into an extremum problem and solved with optimization theory. The preliminary simulation results were conformed to those of the relevant experiments as a whole, which proves that the new calculation method for the collision is available for the design of the anti-impact protection device. Related Articles | Metrics

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Damage Mechanism Analysis of Inner-stiffened Cylindrical Shell Subjected to Underwater Explosion Bubble WANG Hao,WANG Xian-zhou, LIU Jun,CHENG Yuan-sheng 2012, 32(6): 111-115.  DOI: 10.3969/j.issn.1006-1335.2012.06.027 Abstract ( )   PDF   The damage mechanism of inner-stiffened cylindrical shell subjected to pulsation and collapse-jet loads from underwater explosion bubbles was analyzed, and the influences of some physical quantities, such as structural parameters, location of satchel charges etc., on the structural deformation characteristics and damage mode were investigated. The research results show that the global structural deformation are mainly caused by the UNDEX bubble expansion impact, and the high speed bubble collapse jet (velocity>100m/s) can cause serious local damage of the structure. Analyses also indicate that the elastic-plastic boundary effect and the free surface effect have significant influence on the shape of the UNDEX bubble. Related Articles | Metrics

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Computational Method for Shock Resistance Analysis of  Piping System of Diesel Engine WANG Hong-wei 1, WANG Yu 2, LI Wei-jun 3 2012, 32(6): 116-119.  DOI: 10.3969/j.issn.1006-1335.2012.06.028 Abstract ( )   PDF   According to the characteristics of shock resistance computation for pipeline system, a simple method based on beam theory was presented. It was found that the computational result is in good accordance with that from the finite element simulation. Thus, this method provides a good reference for shock resistance design of the pipeline systems. Related Articles | Metrics

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Shock Limited Load of Equipment and Analysis Examples ZHAO Jian-hua 1, WANG Yu 2, GAO Hong-bin 1, SUN Yu-peng 1 2012, 32(6): 120-124.  DOI: 10.3969/j.issn.1006-1335.2012.06.029 Abstract ( )   PDF   The anti-shock capability of marine equipment is measured by shock limited load, which is the important content of marine anti-shock research. The shock limited load can be used to select equipments and to design vibration isolation system. Shock limited load is the inherence characteristic of equipment. Input acceleration or shock spectrum is used to measure the shock limited load. The shock failure rule of marine diesel engine includes stress limit, strain limit, displacement limit and failure of connecting structures. Shock response simulation analysis of TBD234V6 diesel engine was done in this paper. It was found that under the shock load prescribed by BV043/85 standard, the stress exceeds the limitation value in the stop condition. The relative deformation between two parts can reach one or two millimeters, which indicates that the parts in assembling should avoid interference from the others. Specially, the deformation of crankshaft showed that the oil film is destroyed. Thus, the engine should be isolated. The shock response of the bolted joints of the engine base was calculated. The results indicated that the bolted joints are separated. Related Articles | Metrics

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Dynamic Response of Stiffened Square Plate Subjected to Jets Load due to Underwater Explosion Bubbles MU Jin-lei 1, LI Hai-tao 2 2012, 32(6): 124-129.  DOI: 10.3969/j.issn.1006-1335.2012.06.030 Abstract ( )   PDF   In order to study the effect of the liquid jets from collapsed bubbles to the structure, the commercial transient dynamic FEM software MSC.Dytran was used to simulate the dynamic response of stiffened plate subjected to underwater explosion. The explosion was beneath or on the sides of the structure. The tracks of the bubbles in simulation were in accordance with those of the experimental result, which verifies the feasibility of the simulation methods. The flow filed conditions and response of the stiffened square plate were also analyzed. It was concluded that the load of jets can cause serious local damage of the structure, and it has to be considered in the research of near field explosion. Related Articles | Metrics

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Simulation of Impact Contact Based on ANSYS Software GAO Xiao-han 1, WANG Yu 1, 2, DU Jian-ye 2， HE Shao-hua 2 2012, 32(6): 130-133.  DOI: 10.3969/j.issn.1006-1335.2012.06.031 Abstract ( )   The impact contact algorithm was studied and realized by means of ANSYS software. The study included three aspects: the selection of contact algorithm, the determination of contact stiffness, and the best balance between convergence and accuracy. A general method that dealt with these problems by ANSYS software was summed up. And this method was used in the impact analysis of a ship’s thrust bearing. Result of the example shows that this method is successful because of its good convergence and small amount of infiltration. The consistency between the calculation result and engineering experience indicates that this method is feasible and effective. Related Articles | Metrics

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Motion Response of Rigid Ship under Shock Wave GAZHANG Wen-peng 1, ZONG Zhi 1, WANG Yu 2, DU Zhi-peng 2 2012, 32(6): 134-136.  DOI: 10.3969/j.issn.1006-1335.2012.06.032 Abstract ( )   PDF   Under the action of shock wave due to non-contact underwater explosion, ships with small size or large stiffness will have the response of large rigid-body motion. Based on Taylor plate equation, and taking the additional mass of transverse motion into account, the kinematic equations of 2D cross-section under the shock wave action due to the non-contact underwater explosion were established. And the response of the rigid body motion of a ship to the explosion was calculated. The results are in good agreement with the experimental data, which shows that the present method can be applied in prediction of motion response of ships under shock wave action. Related Articles | Metrics

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Effects of Bearings Support Characteristics on Shaft Stability SUN Bing-nan，XIE Fan，JING Jian-ping 2012, 32(6): 137-140.  DOI: 10.3969/j.issn.1006-1335.2012.06.033 Abstract ( )   PDF   The rotor-bearing system was modeled with consideration of different types of lubrication bearings. The stability of the rotor systems are then investigated. The logarithmic attenuation of the rotor-bearing system with different bearing parameters was studied. Via comparison, the influence of some key parameters on the shaft stability was discussed. Related Articles | Metrics

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Bending Vibration Performance of Sheet-shaped Phononic Crystals HE Yu-yang 1, 2, JIN Xiao-xiong 1, WEI Huan 1 2012, 32(6): 141-145.  DOI: 10.3969/j.issn.1006-1335.2012.06.034 Abstract ( )   PDF   The finite element model of sheet-shaped phononic crystals was established with Patran software, and the results of simulation showed that the band gap was between 164 and 353 Hz. A simplified model of Z-mode of bending vibration for sheet-shaped phononic crystals was proposed. The effect of material parameters, such as the density of scatter, the thickness of coating, and the constraint condition on the band gap was analyzed. The phononic crystal samples made of acrylic, steel, and silicone were provided, and their transmission characteristics were tested experimentally. The result shows that there are obvious band gaps below 2 000 Hz, and the attenuation of vibration amplitude can exceed 40 dB. This work may provide a reference for application of phononic crystals to vibration attenuation of sheet-shaped component parts of automotives. Related Articles | Metrics

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Finite Element Analysis of Vibration Reduction of Pipelines with Different Perforated Damping CHEN Yuan,RUAN Xiao-hui,HUANG Tao,ZHOU jing-dong,ZHOU Xiao-qiang,ZHOU Ming-gang 2012, 32(6): 146-149.  DOI: 10.3969/j.issn.1006-1335.2012.06.035 Abstract ( )   PDF   The structural dynamic problems of viscoelastic composite pipelines were calculated by means of ANSYS software based on the modal strain energy method, and the APDL code was used for programming. The results were compared with those from the Matlab code. Some results of the effect of different perforating patterns on noise reduction of the pipeline’s damping structure were provided. This work may provide a reference for similar engineering projects. Related Articles | Metrics

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Parameter Identification of Material Characteristics of Hard Coatings Using Vibration Beam Method HAN Qing-peng 1, SUN Wei 2， QI Fei 2 2012, 32(6): 150-153.  DOI: 10.3969/j.issn.1006-1335.2012.06.036 Abstract ( )   PDF   The mechanical characteristic parameters of hard coating material TiZrN was identified based on vibration beam method. Firstly, the measurement principle and the testing process of the vibration beam method were introduced. Then, the testing system was built to identify the mechanical characteristic parameters of the hard coating materials. The mechanical characteristic parameters of the hard coating material TiZrN were measured, and the intrinsic frequencies and loss factors of the bending modals of the corresponding structural coatings were obtained. Furthermore, the elastic modulus and loss factor of hard coating material TiZrN were estimated. Finally, the possible errors of the system were analyzed. Based on the identification formula of the vibration beam method, and the sensitivity of the identification results to the material parameters was described. Related Articles | Metrics

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Properties of Vertical Vibration of Floating Pile in Viscoelastic Soil YU Lie 1, LIN Bin-bin 2 2012, 32(6): 154-157.  DOI: 10.3969/j.issn.1006-1335.2012.06.037 Abstract ( )   PDF   Regarding the soil portion below the floating pile as a virtual soil pile, and the soil around the pile as a fractional derivative viscoelastic medium, the vertical vibration of the floating pile was solved. The boundary conditions of the soil and the pile and their continuity conditions were considered. The influence of main mechanical parameters of the pile and the soil on the complex stiffness at the head of the floating pile was investigated. The result indicates that the order of the fractional derivative has some influence on the real part and imaginary part of the complex stiffness. The constraint effect of the soil on the pile will be larger when the length of the pile is longer. The real part of the complex stiffness at the pile head will decrease when the model’s constitutive parameter increases. And the influence of the model’s constitutive parameter on the imaginary part of the complex stiffness is somewhat complicated. Related Articles | Metrics

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GA-optimized Fuzzy Control of Semi-active Suspension System for High-speed Train SONG Yu，CHEN Wei-dong，ZHANG Jin 2012, 32(6): 158-164.  DOI: 10.3969/j.issn.1006-1335.2012.06.038 Abstract ( )   PDF   In order to reduce lateral vibration of high-speed strain, the dynamics model for semi-active suspensions of vehicles was established in ADAMS/Rail code. Programs for genetic algorithm procedures were written in MATLAB code using a mixed encoding method of float and decimal numbers, and the method of adaptive genetic crossover and mutation probability based on standard deviation of fitness values. The membership functions, fuzzy rules, quantification factors and scaling factors were optimized. Using the RMS of lateral vibration at the front and the rear of the vehicle’s body as the performance index of the genetic algorithm, the fuzzy controller of the semi-active suspension was constantly optimized. The joint simulation results show that using GA-optimized fuzzy semi-active suspension can effectively reduce the lateral vibrations and improve the ride comfort of vehicles. Related Articles | Metrics

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Rethinking about the Construction and Type Selection of Anti-vibration Track in Subway SUN Hong-qiang 2012, 32(6): 165-168.  DOI: 10.3969/j.issn.1006-1335.2012.06.039 Abstract ( )   PDF   Based on the experience of subway’s anti-vibration track construction in Harbin, and with the consideration of new situations and issues occurring in the process of revising the standard code related to the construction, the work of type-selection, design and construction of anti-vibration track of subways were rethought. Some ideas for future improvement were put forward, including the consideration of special requirements of the different vibration reduction measures to the design and construction, attention to the reliability in application and the convenience in the maintenance and repairing. Based on the large amount of field testing data, the misunderstanding in application and evaluation nowadays was corrected, which may guide the work of type-selection, design and construction of the anti-vibration tracks in the future. Related Articles | Metrics

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Robust Optimization Algorithm for Powertrain Mounting System   of Automobiles WANG　Xin-kan 1，2,CHEN Jian 1，2 2012, 32(6): 169-174.  DOI: 10.3969/j.issn.1006-1335.2012.06.040 Abstract ( )   PDF   Considering the influence of the uncertainty of design variables on the optimization design, the robust optimization design theory was used to build a robust model for the powertrain mounting system of automobiles. In this model, decoupling of energy distribution was taken as the target, the stiffness parameters of the mounting was taken as a design variable, and the mean and standard deviation of the target results were considered. Aiming at the problem that the particle swarm algorithm was easy to fall into a local optimal solution, a hybrid particle swarm algorithm was adopted to optimize the stiffness of the mounting of the powertrain mounting system, and the Monte Carlo method was used to analyze the optimized results to examine the influence of the variety of design values on the objective function. The results show that the method can improve the robustness of the mounting system effectively. Related Articles | Metrics

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Analysis of Radiation Noise Characteristics of Tires with Different Tread Patterns ZHOU Hai-chao,WANG Guo-lin,LIANG Chen 2012, 32(6): 175-178.  DOI: 10.3969/j.issn.1006-1335.2012.06.041 Abstract ( )   PDF   The tire/road noise is one of the main noise sources of both traffic environment noise and the car’s noise. The vibration and radiation noise characteristics of rolling tires were analyzed by means of the virtual prediction method. The acceleration response spectrum of the rolling tires was acquired through analyzing the dynamic response under the road impact excitations by using the modal superposition approach. The acceleration data of the rolling tire surface was imported into the acoustics analytic software as the input load. Using boundary element method, the radiation noise characteristics of the rolling tire were calculated and analyzed. The distribution and character of the noise of the tire with different tread patterns were discussed. It was found that the tread patterns have a large influence on the radiation noise characteristics of the rolling tires, and reduction of the mass of the tread patterns will enhance the radiation noise. Related Articles | Metrics

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Fast Multipole Boundary Element Method for Prediction of Ship Cabin’s Noise CUI Xiao-bing,JI Zhen-lin,WU Yao 2012, 32(6): 179-183.  DOI: 10.3969/j.issn.1006-1335.2012.06.042 Abstract ( )   PDF   The fast multipole boundary element method (FMBEM) was developed to predict the ship cabin’s noise. Considering the vibration, rigid and impendence boundary conditions, the sound pressure contours on the surface and the SPLs at the monitoring point were calculated. The numerical method was validated by comparing the data with the numerical results from Virtual.Lab acoustics software. In addition, the FMBEM was proved efficient for the acoustic computations of large scale problems through comparison of computer time consuming of the FMBEM with that of the conventional BEM. Related Articles | Metrics

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Analysis of Whole-body Vibration Signals for Aero-engines Based on Harmonic Wavelet XU Tao 1, 2, JIN Yan 1 2012, 32(6): 184-188.  DOI: 10.3969/j.issn.1006-1335.2012.06.043 Abstract ( )   PDF   A method for analyzing whole-body vibration signals of aero-engines was proposed based on harmonic wavelet. Firstly, the vibration signal was processed with harmonic wavelet transformation and the time-frequency presentation was derived. Then, the feature frequency of the vibration signal was obtained based on the presentation. Finally, vibration fault of the aero-engine was identified based on the comparison between the feature frequency and the base frequency. Experiment result shows that the method proposed can identify three classical vibration fault modes accurately. Compared with wavelet analysis method, the method with harmonic wavelet processes has a better performance for identifying vibration fault and is suitable for analyzing vibration signals. Related Articles | Metrics

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Study on Wavelet Denoising Algorithm Based on Improved Threshold Function and Maximal Overlap Discrete Wavelet Packet Transform DAI Hai-bo,SHAN Rui,WANG Huan-peng,ZHANG Yan 2012, 32(6): 189-193.  DOI: 10.3969/j.issn.1006-1335.2012.06.044 Abstract ( )   PDF   Aiming at the issue of threshold function setting by using wavelet transform signal denoising, an improved method of threshold function based on the classical method of soft and hard threshold function denoising was presented. After this improved threshold function method and the maximal overlap discrete wavelet packet transform were combined, a wavelet denoising method of improved threshold function was obtained. Simulation results obtained from Matlab software indicated that this method can improve signal-to-noise ratio(SNR) of the reconstructed signal, remove the noise effectively, and reserve the main characteristics of the original signals. So, it is better than the traditional methods. This method has a practical significance in application of stock denoising. Related Articles | Metrics

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Optimization of Sandwich Plate with Porous Damping Core Using Homogenization Theory SHI Lei，ZHENG Ling 2012, 32(6): 194-198.  DOI: 10.3969/j.issn.1006-1335.2012.06.045 Abstract ( )   PDF   The constrained layer damping plate with the damping layer having periodically distributed square holes was designed. The equivalent elastic tensors of the porous damping layer were calculated by using homogenization method. The finite element model of the constrained layer damping plate considering the homogenization of the porous damping layer was developed and its loss factor was calculated. The size of square cells was optimized to maximize the loss factor of the porous damping composite plate through searching the optimal equivalent shear modulus of the porous damping layer. The numerical example was given to demonstrate the effectiveness of the proposed approach. The results show that the optimization of the square cells can enhance vibration energy dissipation of the porous composite plate and achieve an effective attenuation of amplitudes. In addition, the consumption of the damping material can be reduced significantly. This method demonstrates a potential application in structural vibration control. Related Articles | Metrics

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Experimental Study on Centrifugal Pump Vibration in   Different Operation Conditions CHEN Chang-sheng 1,MA Jun 2, LIU Rui-feng 1,ZHOU PU 1, WANG Qiang 1 2012, 32(6): 199-202.  DOI: 10.3969/j.issn.1006-1335.2012.06.046 Abstract ( )   PDF   Multi-loaded operation is always a feature of marine equipment. Experiments were done on marine centrifugal pumps to study the influence of the shifting-load. Variation of parameters related to rotation speed and flow rate was analyzed. Results of experiments confirmed the empirical formula of the rotation speed against vibration. It was concluded that the vibration level of the centrifugal pump is proportional to the forth to ninth power of the rotation speed. Changing of flow rate has a greater influence on low and high frequency vibration than that on intermediate frequency vibration. The influence even becomes much larger at the characteristic frequency of blades of the centrifugal pump. The general conclusion is that when low flow rate operation condition is required, the rotation speed of the pump should be lowered to reduce the operation noise instead of adjusting the valve of the pump. Related Articles | Metrics

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Characteristics of Cutting Noise of Large Cold Saw Machine HAN Hong-liang,LIU Zhi-hong,YI Chui-jie,ZHANG Ying 2012, 32(6): 203-207.  DOI: 10.3969/j.issn.1006-1335.2012.06.047 Abstract ( )   PDF   Unsteady noise test technology and time-frequency refinement analysis methods were used to investigate the cutting noise characteristics of the larger cold saw. The noises in different time-intervals in sawing process were tested. Then, by eliminating the background noise, the cutting noise characteristics were analyzed by the time-frequency refinement analysis method. The results show that the sawing sound field has higher sound pressure level, the radiation frequency has stronger time-varying performance, the sound energy is focused on the lateral direction of the cutting, and high-frequency is very obvious in the noise. This work may provide a technical support for noise test, sound field characteristics analysis and noise control of some complex machines such as fans, compressors, etc. Related Articles | Metrics

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Noise Control of UHV Substation's DC De-icing Device SHEN Lv-yuan 1, YU Xiang-dong 2, WANG Wei-guo 3 2012, 32(6): 208-212.  DOI: 10.3969/j.issn.1006-1335.2012.06.048 Abstract ( )   PDF   DC de-icing device is a new type of device jointly developed by China’s Electric Power Research Institute and Hunan Electric Power Design Institute after the frost disaster in 2008. This device has been widely used in various large substations to ensure the secure operation of power systems. But the device’s operation also has caused a high substation’s environmental noise which needs to be controlled. In this paper, the noise control engineering of the Jinhua 500KV Shuanglong substation’s DC de-icing device was introduced to clarify the principle and the calculation process of engineering design. Related Articles | Metrics