• International Journal of Naval Architecture and Ocean Engineering
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• 제8권2호
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• pp.137-152
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• 2016

This paper studied the dynamic response of a new gasbag-type floating bridge under the effect of a moving load. The arbitrary Lagrangian-Eulerian (ALE) method was used to simulate the movement of seawater and air, and the penalty-based method was used to study the coupling between gasbags and fluid. A three-dimensional finite element model of the floating bridge was established, and the numerical model was verified by comparing with the experimental results. In order to prevent resonance, the natural frequencies and flexural mode shapes were analyzed. Based on the initial state analysis, the dynamic responses of the floating bridge subjected to different moving loads were investigated. Vertical displacements and radial deformations of gasbags under different loads were compared, and principal stress distributions of gasbags were researched while driving. The hinge forces between adjacent modules were calculated to ensure the connection strength. Besides, the floating bridge under wave impacting was analyzed. Those results can provide references for the analysis and design of this new floating bridge.

• 한국정밀공학회지
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• 제14권7호
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• pp.91-98
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• 1997

Because of a complicated behavior of fatigue in mechanical structures, the analysis of fatigue is in need of much researches on life prediction. A method is developed for the dynamic tensile strength analysis by simple tensile test, which is for the failure life prediction by lethargy coefficient of various materials. Then it is programed to analyze the failure life prediction of mechanical system by virtue of fracture. Thus the dynamic tensile strength analysis is performed to evaluate life parameters as a numerical example, using the developed method.

• 대한기계학회논문집A
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• 제24권9호
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• pp.2259-2265
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• 2000

A dynamic modeling of a rotating pretwist blade which interacts with the fluid is proposed in this study. The hybrid deformation variable modeling method is employed to derive the equations of motion. The external force and moment induced by the fluid (with fixed configurations of the blade) are obtained by fluid flow analysis and tabulated in a database. This database is efficiently utilized to save the computational effort to calculate the dynamic response of the blade. The numerical results show that the fluid affects the transient response as well as frequency characteristics of the system.

• Structural Engineering and Mechanics
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• 제59권2호
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• pp.243-259
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• 2016

This research develops a finite element code for the transient dynamic analysis of tapered fiber reinforced polymer (FRP) poles with hollow circular cross-section and flexible joints used in power transmission lines. The FRP poles are modeled by tapered beam elements and their flexible joints by a rotational spring. To solve the time equations of transient dynamic analysis, precise time integration method is utilized. In order to verify the utilized formulations, a typical jointed FRP pole under step, triangular and sine pulses is analyzed by the developed finite element code and also ANSYS commercial finite element software for comparison. Thereafter, the effect of joint flexibility on its dynamic behavior is investigated. It is observed that by increasing the joint stiffness, the amplitude of the pole tip deflection history decreases, and the time of occurrence of the maximum deflection is earlier.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.240-243
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• 2005

Osteoporosis, one of the age-related disease causes vertebra body fracture due to weakening trabecular bone and makes a substantial effect on load sharing among vertebras. Recently, vertebroplasty is one of the most popular treatment, as augmenting PMMA into vertebra. Biomechanical studies about vertebroplasty have been evaluated by several experiments or analysis under static loading but there has been no study on response under dynamic loading. This study included the FE analysis of patients who treated vertebroplasty under dynamic loading. For this study, 3-D FE model of lumbar spine(L1-L2) was modeled from CT scanning data and compared with experimental results in vitro in order to validate this model. Biomechanical behavior about each of normal person, osteoporotic patient and patient treated vertebroplasty for quantitative evaluations of vertebroplasty was compared and investigated.

• Journal of Mechanical Science and Technology
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• 제19권spc1호
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• pp.255-264
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• 2005

In this paper, a practical bushing model is proposed to improve the accuracy of the vehicle dynamic analysis. The results of the rubber bushing are used to develop an empirical bushing model with an artificial neural network. A back propagation algorithm is used to obtain the weighting factor of the neural network. Since the output for a dynamic system depends on the histories of inputs and outputs, Narendra algorithm of 'NARMAX' form is employed to consider these effects. A numerical example is carried out to verify the developed bushing model. Then, a full car dynamic model with artificial neural network bushings is simulated to show the feasibility of the proposed bushing model.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.606-621
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• 2004

A dynamic analysis using a hybrid finite element method was performed to characterize the effects of a number of manufacturing errors on bearing forces and critical tooth stress in the elements of a planetary gear system. Some tolerance control guidelines for managing bearing forces and critical stress are deduced from the results. The carrier indexing error for the planet assembly and planet runout error are the most critical factors in reducing the planet bearing force and maximizing load sharing, as well as in reducing the critical stress.

• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.819-828
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• 2002

An analytical method is presented for evaluation of the steady state periodic behavior of nonlinear systems. This method is based on the substructure synthesis formulation and a MS (multiple scales) procedure, which is applied to the analysis of nonlinear responses. The proposed procedure reduces the size of large degrees-of-freedom problem in solving nonlinear equations. Feasibility and advantages of the proposed method are illustrated with the nonlinear rotating machine system as an example of large mechanical structure systems. In addition, its efficiency for nonlinear response prediction will be shown by comparison of other conventional methods.

• 대한기계학회논문집A
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• 제36권8호
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• pp.945-951
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• 2012

본 논문에서는 하부 프레임 구조가 보다 단순해진 분말류 운송차량인 벌크시멘트 트레일러의 정동적 특성을 유한요소해석을 통하여 분석하였다. 이를 위하여 벌크시멘트 트레일러가 받는 하중의 대부분을 지지하는 섀시 프레임과 탱크부분을 상용 유한요소해석 소프트웨어인 ANSYS를 이용하여 삼차원 상세 유한요소모델링을 수행하였다. 자유진동해석을 통하여 차체의 동적특성을 이해하는데 필수적인 벌크시멘트 트레일러 몸통의 고유진동수와 진동모드를 분석하였다. 또한, 정적인 응력해석을 통하여 트레일러의 취약부위를 찾은 후 다구찌 실험계획법을 적용하여 경량화를 시키면서도 취약부위의 강도를 높일 수 있는 방안을 제시하였다.

• International Journal of Aeronautical and Space Sciences
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• 제6권1호
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• pp.52-60
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• 2005

The CFD coupled aeroelastic analyses have significant advantages over linear panel methods in their accuracy and usefulness for the simulation of actual aeroelastic motion after specific initial disturbance. However, in spite of their advantages, a heavy computation time is required. In this paper, a method is discussed to save a computational cost in the time domain aeroelastic analysis based on the system identification technique. The coefficients of system identification model are fit to the computed time response obtained from a previously developed aeroelastic analysis code. Because the non-dimensionalized data is only used to construct the model structure, the resulting model of the unsteady CFD solution is independent of dynamic pressure and this independency makes it possible to find the flutter dynamic pressure without the unsteady aerodynamic computation. To confirm the accuracy of the system identification methodology, the system model responses are compared with those of the CFD coupled aeroelastic analysis at the same dynamic pressure.