• International Journal of Safety
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• v.6 no.1
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• pp.7-10
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• 2007

In this paper, we found that modification of the local flexibility (or local stiffness) of the 4 parts on which shock absorbers are mounted in the vehicle body has some influence the level of ride safety and comfort. Multi-body dynamic analysis considering the flexibility of the vehicle body is performed using MSC/ADAMS and MSC/NASTRAN. More concretely speaking, natural frequencies and mode shapes computed by MSC/NASTRAN are used as input data for multi-body dynamic analysis in MSC/ADAMS. It is confirmed that the ride comfort can be improved by appropriately changing the local stiffness of the vehicle body through several simulations using MSC/ADAMS.

• Composites Research
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• v.16 no.5
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• pp.7-14
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• 2003

Modeling of thick composite structures for finite element analysis is relatively complicated. 2-D plane elements may cause inaccurate result since the plane stress condition cannot be applicable in these structures. Therefore a 3-D modeling should be used. However, the difficulty to model all the layers with different material properties and ply orientation arise in this case. In this paper, an equivalent modeling is proposed and numerically tested for analysis of thick composite structures. By grouping layers with same material and ply orientation, number of elements through the thickness is remarkably reduced and still the result is close enough to the one from a detail finite element model. MSC/NASTRAN and PATRAN are used for the analysis. The proposed modeling technique has been applied for analysis of composite rotor hub system designed by Korea Aerospace Research Institute(KARI). Using the proposed equivalent modeling technique, we could conduct stress analysis for the hub system and check the safety factor of each part.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.5
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• pp.459-465
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• 2015

There exist different kinds of aircrafts, such as conventional airplane, rotorcraft, fighter, and unmanned aerial vehicle. Their shape and feature are dependent upon their own assigned mission. One of the fundamental analyses performed during the aircraft design is the structural analysis. It becomes more complicated and requires severe computations because of the recent complex trends in aircraft structure. In order for efficiency in the structural analysis, a simplified approach, such as equivalent beam or plate model, is preferred. However, it is not clear which analysis will be appropriate to analyze the realistic configuration, such as an aircraft wing, i.e., between an equivalent beam and plate analysis. It is necessary to assess the limitation for both the one-dimensional beam analysis and the two-dimensional plate theory. Thus, in this paper, the static structural analysis results obtained by EDISON solvers were compared with the three-dimensional results obtained from MSC NASTRAN. Before that, EDISON program was verified by comparing the results with those from MSC NASTRAN program and other analytic solutions.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.674-684
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• 2002

선박이 물품의 제하 및 적하를 위하여 컨테이너 부두에 접항시 선박의 케이슨과의 충돌에 의한 케이슨의 발생 응력을 파악함으로써 구조 안정성을 검토하였다. 선박이 일정 속도로 항만에 접항시 선박은 케이슨에 부착된 방충재와 충돌하게 된다. 케이슨에 부착된 방충재는 선박의 운동에너지를 흡수하여 케이슨으로 전달되는 전달 에너지를 최소화하여 케이슨의 구조물에 발행하는 응력을 최소화하도록 설계한다. (중략)

• Journal of Ship and Ocean Technology
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• v.3 no.2
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• pp.27-48
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• 1999

The paper is concerned with application to develop the expert system, which structural analysis and design process for tower cranes. The system is organized into three groups. One is pre-processor for creating input data files, another is `model former' which combines knowledge-base with inference engine for automatic generating structural analysis models, a third is application group for final analysis checks. In this study, geometric subroutine of `model former' designates node positions, nodes, elements numbers and element types. Load data subroutine computes weight of tower crane and device, slewing force, cargo load, wind force form rules or equations in knowledge-base. Also, Property and boundary subroutine applies element properties and boundary conditions to suitable elements and nodes. Design and analysis expert system for tower crane integrates these subroutine, `model former' and pre-processor. RBR(Rule-Base Reasoning) was adopted for a reasoning strategy of this expert system. And this expert system can produce structural analysis model and data, which can be used in ordinary structural analysis program (SAP, ADINA or NASTRAN, etc.). In this paper, this expert system produces format of the analysis model data, which are used in MSC/NASTRAN. The main discussions included in the paper are introduction of the tower crane and structural analysis, composition of the design expert system for tower crane and structural analysis using the expert system.

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.33-44
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• 2003

This paper describes the design and analysis technology of composite flexure and composite paddle-type blade which are all key technologies on hingeless rotor system. Through replacing the existing metal or engineering plastic flexure part with composite part, Several required structural analysis were accomplished, which are static analysis by using NASTRAN and dynamic analysis by using FLIGHTLAB. The dynamic characteristics of composite hingeless hub attached with paddle-type blade was also investigated. Further more, small-scaled paddle-type blade was designed using froude scaled properties of existing full size blade. Through this design procedure of composite paddle-type blade, the structural design method was achieved. These results will be applied to accomplishing current project named as "the development of next-generation helicopter rotor system."

• Composites Research
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• v.18 no.4
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• pp.52-58
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• 2005

A cyclocopter propelled by the cycloidal blade system, which can be described as a horizontal rotary wing, is a new concept of VTOL vehicle. In this paper, optimized structure design is carried out for the aerodynamically optimized cyclocopter rotor system. Database is obtained fer design variables such as stacking sequence (ply angles), number of plies and spar locations through MSC/NASTRAN and optimum values are determined by RSM and some other optimizing processes. For the rotor system including optimized blade and composite hub m, the maximum stress by static analysis is within the failure criteria. And the rotor system is designed for the purpose of avoiding possible dynamic instabilities by inconsistency between frequencies of rotor rotation and some low natural frequencies of rotor.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.507-512
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• 2001

In this work, tool holder system has been designed and builted to measure cutting forces in diamond turning. This system design includes a 3-component piezo-electric tranducer. Initial experiments with tool holder system included verification of its predicted dynamic characteristics as well as a detailed study of cutting parameters. Tool holder system is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of structure is simulated by MSC/NASTRAN, for the purpose of developing the effective design. Many cutting experiments have been conducted on 6061-T6 aluminum. Tests have involved investigation of velocity effects, and the effects of depth and feedrate on tool force. Forces generally increase with increasing depth of cut. Increasing feedrate does not necessarily lead to higher forces.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.12
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• pp.1229-1235
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• 2008

ELT(emergency locator transmitter) has assisted in the rescue of thousands of lives in distress. Aviators, mariners and land users being equipped with distress beacons are capable of transmitting distress signals to the satellites in emergency situations anywhere in the world. In this paper, Drop/Impact simulation was performed for ELT Body-case. FE model for Body-case was constructed with MSC/Dytran and refined using the Karas example simulation for Body-case prototype. Shock/impact survivability analysis was performed for ELT operations. FE model constructed with MSC/Nastran. Transient response analysis for refined ELT model was perfomed for ELT under impact shock loading condition.

• Composites Research
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• v.14 no.5
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• pp.20-25
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• 2001

This paper deals with finite element analysis for free vibration and forced sinusoidal vibration of Ka- and Ku- band antenna structures using MSC/NASTRAN. The structures are designed to satisfy minimum resonance frequency requirement in order to decouple the dynamic interaction of the satellite antenna with the spacecraft bus structure. The large mass method was utilized to analyze output acceleration according to the forced sinusoidal vibration inputs in X-, Y- and Z- directions. The analysis results can also be used thor verification experimental planning of satellite antenna.