• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1180-1184
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• 2000

The dynamic design analysis method (DDAM) to analyze and evaluate shock response of the equipment system mounted in ships are discussed. Theoretical background of the DDAM based on the general shock response analysis was introduced. Spectrum dip effect between the equipment system and supporting structure was specially focused being peculiar to general shock response analysis. Actual shock design values used in the DDAM were reviewed in their category, general trend and establishing process. Aspects of DDAM analysis using MSC/NASTRAN were shortened. As a conclusion DDAM is regarded as a reasonable way of analysis for the onboard equipment system due to the underwater shock.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.2
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• pp.114-120
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• 1999

The DDAM(Dynamic Design Analysis Method) has been the most popular method for the shock response analysis of naval shipboard equipment. It was common to model the equipment as a simplified mass-spring system with multi degree of freedom in DDAM. Nowadays, however, it is necessary to adopt the finite element method for the shock response analysis due to the complexity of equipment. In this study, the DDAM program is developed to evaluate the performance of shock-resistance of FEM models using MSC/NASTRAN DMAP(Direct Matrix Abstraction Program) which provides the practical tools in interfacing with the externally developed program. Through the numerical test of the structural components and comparison with the results of ANSYS DDAM, it is confirmed that the developed program can be applicable to analyze the shock responses of the shipboard equipments.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.11 s.116
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• pp.1132-1139
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• 2006

Non-contact underwater explosions against surface ship could cause extensive equipment damage during wartime service. Thus, the need to develop methods for the design of shock resistant equipment structures and systems was strongly established. In analytical methods, DDAM(Dynamic Design and Analysis Method) and transient repsonse method are used for ship shock design. In this paper, to analyze the characteristics of DDAM, medium weight shock test, DDAM and transient response analysis for missile system equipment are performed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.4 s.121
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• pp.317-323
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• 2007

Non-contact underwater explosions against surface ships could cause extensive equipment damage and render the ship inoperative. As an analytical method, DDAM(dynamic design and analysis method) is used for ship shock design. In this paper, in order to verify the finite element model of large shipboard equipment, modal test of equipment was performed. Major objective of this paper is to describe shock analysis methodology for large shipboard equipment attacked to the top and bottom foundations.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.256-257
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1221-1222
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• 2010

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.5
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• pp.76-82
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• 2010

In this study, we carried out to evaluate the shock-proof of a large scale motor for the naval vessel using dynamic design analysis method (DDAM) and full transient dynamic analysis. Analytical models for main assemblies (motor frame, rotor and stator assembly) were consisted of the tetrahedral solid elements and the equipments which installed in the upper side of the motor were substituted the mass elements. And we also modelled resilient mounts of a motor using the beam elements with appropriate directional stiffness. The DDAM was conducted according to NRL memorandum report 1396 and the full transient dynamic analysis was performed applying directional triple half triangle shock wave to the motor using ANSYS 12. As a result, we could compare of the results according to each analytic method and find the motor to satisfy the design criteria of the maximum stress and deformation.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.98-103
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• 2002

In this paper, shock analysis was performed for coarse and fine mesh model using MSC/NASTRAN and ANSYS after substituting the foundation of deck mounted equipment of marine ship for mass-spring system. In order to determine input file in MSC/NASTRAN, dynamic response analysis was also performed using DDAM based on the calculation in the range of low frequency. It was confirmed that the coarse mesh model has the sufficient effective weight in a lower degree mode compared to fine mesh model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.507-508
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• 2007

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.870-872
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• 2007

Sensor networks have been widely applied for data collection. Due to the energy limitation of the sensor nodes and the most energy consuming data transmission, we should allocate as much work as possible to the sensors, such as data compression and aggregation, to reduce data transmission and save energy. Querying extreme values is a general query type in wireless sensor networks. In this paper, we propose a novel querying method called Two-Level Filter (TLF) for querying extreme values in wireless sensor networks. We first divide the whole sensor network into domains using the Distributed Data Aggregation Model (DDAM). The sensor nodes report their data to the cluster heads using push method. The advantages of two-level filter lie in two aspects. When querying extreme values, the number of pull operations has the lower boundary. And the query results are less affected by the topology changes of the wireless sensor network. Through this method, the sensors preprocess the data to share the burden of the base station and it combines push and pull to be more energy efficient.