• 대한기계학회논문집A
• /
• 제37권9호
• /
• pp.1133-1140
• /
• 2013

컴퓨터 해석모델은 물리현상을 바탕으로 단순화된 모델을 구축하고 해를 구하는 유용한 도구이나, 많은 경우 단순화 가정 또는 입력변수 정보의 미비나 불확실성으로 인해 실제와 차이가 발생한다. 본 연구에서는 이러한 문제에 대해 베이지안 확률이론을 이용하여 실측데이터를 통해 해석모델을 보정하는 방법을 소개하고 이를 파이로 작동기구의 탄소성 압착 문제에 적용한다. 파이로 작동기구는 고에너지의 재료를 원격으로 폭발시켜 작동하는 장치로 그 작동의 신속한 계산을 위해서 단순한 수학모델을 구축하고 실험데이터를 토대로 미지의 입력변수를 확률적으로 보정하였다. 이 때, 확률적 추정을 위해서는 현대적 계산통계기법의 하나인 Markov Chain Monte Carlo 기법을 이용하였으며, 최종적으로 그 결과를 압착거동해석에 활용하여 작동기구의 신뢰도를 평가하였다.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2007년도 춘계학술대회 논문집
• /
• pp.272-275
• /
• 2007

This paper is concerned with modified integration algorithm on the strain-space for rate and temperature dependent elasto-plastic constitutive relations in order to obtain more accurate results in numerical implementation. The proposed algorithm is integrated analytically using integration by part and chain rule and then is applied to the 2-stage Lobatto IIIA with second-order accuracy. It has advantage that is able to consider the convective stress rates on the yield surface of the strain-space. Also this paper is carried out the iteration procedure using the Newton-Raphson method to enforce consistency at the end of the step. And the performance of the proposed algorithm for rate and temperature dependent constitutive relation is illustrated by means of analysis of adiabatic shear bands.

• 한국정밀공학회지
• /
• 제17권6호
• /
• pp.199-209
• /
• 2000

Particles reinforced MMCs have higher specific modulus, higher specific strength, better properties at elevated temperatures and better wear resistance than monolithic metals. But the coefficient of thermal expansion(CTE) of Al6061 is 5 times larger than that of SiCp. The discrepancy of CTE makes some residual stresses inside of MMCs. This work investigates Si$C_p$/Al6061 composites at high temperatures in the microscopic view by three-dimensional elasto-plastic finite element analyses and compares the analytical results with the experimental ones. The theoretical model is not able to consider the nonuniform shape of particle. So the shape of particle is assumed to be perfect global shape. And also particle distribution is not homogeneous in experimental specimen. It is assumed to be homogeneous in simulation model. The type of particle distribution is face-centered cubic array(FCC array). Furthermore, non-homogeneous distribution is modeled by combination of several volume fractions.

• 한국공간구조학회논문집
• /
• 제6권2호
• /
• pp.85-92
• /
• 2006

본 연구에서는 철근콘크리트 프리캐스트 대형판의 접합부 설계방법 및 해석방법에 대해서 연구를 수행하였다. 접합부의 설계방법은 수평접합부와 수직접합부의 구조적 거동에 대한 안정성 및 일체성을 확보하기 위한 설계법을 제시하였고, 접합부의 해석은 강체스프링 모델에 의한 탄소성해석을 수행 하였다.

• 한국농공학회논문집
• /
• 제46권2호
• /
• pp.67-75
• /
• 2004

This study aims to investigate the dynamic behaviour of a parabolic arch with initial deflection by using the elasto-plastic finite element model where the von-Mises yield criteria have been adopted. The initial deflection of arch was assumed by the high order polynomial of ${\omega}_i$ = ${\omega}_o$${(1-{(2x/L)}^m)}^n$) and the sinusoidal profile of ${\omega}_i$ = ${\omega}_o$$\sin$(n$\pi$x/L). Several numerical examples were tested considering symmetric initial deflection modes when the maximum initial deflection of an arch is fixed as L/500, L/1000, L/2000 or L/5000. The effects of polynomials order on the dynamic behavior of arch were not conspicuous. The most unfavorite dynamic response occurs when the maximum initial deflection varies from L/1000 to L/4000 if the initial deflection mode is represented by high order polynomials.

• 소성∙가공
• /
• 제12권4호
• /
• pp.302-307
• /
• 2003

Hot rolled strip is cooled by air and water in Run-Out-Table. In this process, phase transformation and shape deformation occurs due to temperature drop. Because of un-ideal cooling condition of ROT, irregular shape deformation and phase transformation arise in the strip. which affect the strip property and lead to the residual stress of strip. And these exert effects on the following processes, coiling process, coil cooling process, and re-coiling process. Through these processes, the residual stress becomes higher and severe. For the prediction of residual stress distribution and shape deformation of final product, Finite element(FE) based model was used. It consists of non-steady state heat transfer analysis, elasto-plastic analysis. thermodynamic analysis and phase transformation kinetics. Successive FEM simulation were applied from ROT process to coil cooling process. In each process simulation, previous process simulation results were used for the next process simulation. The simulation results were matched well with the experimental results.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2013년도 추계학술대회 논문집
• /
• pp.87-91
• /
• 2013

Rubber Components have been playing important role for the isolation of noise and vibration of vehicle. This paper is presented the new method of dynamic modeling of rubber component for simulating the dynamic characteristics of it under the varing loading condition. Rubber dynamic model consists of the hyperelastic, viscoelastic and elasto-plastic characteristics of rubber. Dynamic proporties of rubber are calculated at each preload and frequency conditions, compared to test data, and evaluated the validity of rubber dynamic model. This technique is expected to understand and improve the characteristics of noise and vibration with relation to rubber components.

• 한국정밀공학회지
• /
• 제17권11호
• /
• pp.122-128
• /
• 2000

In this paper, a bulging condition which affect the quality of continuous casting steel was analyzed by using the numerical analytic method. First, solidification analyses were performed for each cooling zone by one-dimensional finite difference method. The bulging deformation of cast slab has been calculated with a two-dimensional elasto-plastic and creep finite element model. The adequacy of the model has been checked against the experimental results. From this study the effects of the process variables such as casting speed, cooling condition and roll pitch were examined. The results from these analyses would be able to apply to the design of continuous casting process.

• Computers and Concrete
• /
• 제19권1호
• /
• pp.7-17
• /
• 2017

In Chinese Design Codes, for super high-rise buildings with complex structural distribution, which are regarded as code-exceeding buildings, elasto-plastic time history analysis is needed to validate the requirement of "no collapse under rare earthquake". In this paper, a 117-story super high-rise building is discussed. It has a height of 597 m and a height-width ratio of 9.5, which have both exceeded the limitations stipulated by the Chinese Design Codes. Mega columns adopted in this structure have cross section area of about $45m^2$ at the bottom, which is infrequent in practical projects. NosaCAD and Perform-3D, both widely used in nonlinear analyses, were chosen in this study, with which two model were established and analyzed, respectively. Elasto-plastic time history analysis was conducted to look into its seismic behavior, emphasizing on the stress state and deformation abilities under intensive seismic excitation.From the comparisons on the results under rare earthquake obtained from NosaCAD and Perform-3D, the overall responses such as roof displacement, inter story drift, base shear and damage pattern of the whole structure from each software show agreement to an extent. Besides, the deformation of the structure is below the limitation of the Chinese Codes, the time sequence and distribution of damages on core tubes are reasonable, and can dissipate certain inputted energy, which indicates that the structure can meet the requirement of "no collapse under rare earthquake".

• 한국추진공학회지
• /
• 제20권5호
• /
• pp.60-69
• /
• 2016

본 연구에서는 케로신-공기 혼합물 데토네이션 계산과 다물질 해석을 기반으로 데토네이션 하중에 의한 얇은 금속관의 열탄소성 거동에 대한 수치계산을 수행하였다. 데토네이션 하중은 케로신-공기 혼합물의 데토네이션을 활용하여 모델링하였으며, 검증을 위해 해석 결과를 C-J 조건과 실험적 셀 직경을 통해 비교 검증하였다. 또한 금속의 탄성/소성 거동을 확인하기 위하여, 소성 거동은 구리의 Taylor impact 문제로, 탄성 거동은 베를리움 평판 떨림 문제를 활용하였다. 온도에 의한 관의 탄소성 거동 변화를 확인하기 위하여 동일한 데토네이션 하중 하에서 초기 온도가 다른 관의 거동을 확인하고 이론식과의 비교를 통해 열연화 효과가 고려되어야 함을 확인하였다.