다중그리드 페리다이나믹 해석법과 다중레벨 손상 매핑을 통한 준정적 취성 균열 전파 해석 기법 연구

조광현(Gwanghyun Jo),하윤도(Youn Doh Ha) 대한기계학회 2022 大韓機械學會論文集A Vol.46 No.3

페리다이나믹 해석법은 비국부 적분 기반 연속체 해석 기술로서 준정적 균열 전파 해석을 위한 내재적 정식화를 수행하면 유한요소법과 같은 국부 모델에 비해 조밀한 시스템 행렬이 얻어진다. 따라서 효율적인 행렬 시스템 해석을 위해 다중그리드 기법을 적용한다. 준정적 균열 전파 해석을 위해서 순차선형해석을 도입한다. 다만 개별 결합이 손상되는 과정을 통해 재료 파괴를 모사하는 페리다이나믹 손상 모델링의 특성 때문에 순차선형해석이 매우 느리게 진행하는 단점이 확인되었다. 본 연구에서는 저차 레벨에서 결합 손상을 구현하고 순차선형해석을 수렴시킨다. 또한 캐스케딕(cascadic) 다중그리드 해석법을 응용하여 고차 레벨로 손상 정보를 매핑하고 순차선형해석을 완료한다. 수렴성 테스트를 통해 개발된 해석 기법을 검증하고 효율적 준정적 균열 전파 해석이 가능함을 확인하였다. Peridynamics is a nonlocal continuum theory based on integro-differential equations without spatial derivatives. Owing to its nonlocality, the implicit formulation for quasi-static crack propagation analysis results in a less sparse system matrix than that for a typical local theory, such as FEM. For efficient matrix calculation, we employ the implicit solution procedure with the multigrid scheme. Failure modeling in peridynamics involves the breaking of the bond between two nodes under a certain damage criterion. Utilizing the sequentially linear analysis (SLA) scheme, this failure model allows for a single bond to be broken at equilibrium points of linear analysis. This makes the entire SLA simulation inefficient. Therefore, a cascadic multigrid scheme is utilized herein to efficiently solve quasi-static problems with the SLA scheme. We also propose a multilevel damage mapping for robust crack propagation in a cascadic multigrid scheme. Further, we present the verification of the robustness of the proposed algorithm based on an m-convergence study.

준정적해석을 이용한 Y형 전단연결부의 Push-out 실험 유한요소해석

김건수 ( Kim Kun-soo ),박기태 ( Park Ki-tae ),한원일 ( Han Oneil ),김상효 ( Kim Sang-hyo ) 한국구조물진단유지관리공학회 2019 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.23 No.2

강-콘크리트 합성구조의 성능을 확보하기 위해서는 전단연결재가 설치된 전단연결부에 대한 전단강도 분석이 필수적이다. 전단연결부의 전단거동을 효율적으로 예측하기 위하여, 전단연결부의 push-out test에 대한 유한요소해석을 수행하였다. 유한요소해석에는 범용 프로그램인 ABAQUS가 사용되었으며, 대상 실험체는 Y형 전단연결재가 적용된 강-콘크리트 전단연결부이다. 유한요소해석에서는 대상 실험체를 구성하는 재료들의 비선형성을 고려하였고, 비선형해석의 수렴문제를 해결하기 위하여 준정적해석을 사용하였다. 본 연구에서 수행된 유한요소해석 결과를 바탕으로 하중-변위곡선과 전단강도를 기존 실험결과와 비교한 결과, 준정적해석을 이용한 유한요소모델은 기존 실험결과를 잘 반영하는 것을 확인하였다.

철골 프레임의 폭발 및 연쇄붕괴해석을 위한 효율적 모델링 기법

전두진(Jeon, Doo-Jin),차은호(Cha, Eun-Ho),한상을(Han, Sang-Eul) 대한건축학회 2015 大韓建築學會論文集 : 構造系 Vol.31 No.9

The blast analysis is limited to unit members because of its long analysis time. So this paper proposes the effective modeling and simulation technique for blast and collapse analysis of steel frame. In this study, analysis for static and blast load are performed with three kinds of elements such as solid element, plate element and thick plate element. Then, the most efficient element for blast and collapse analysis is determined by comparing the reliability of the results and calculation time. Also, quasi-static is applied to the analysis that has to be carried out by the static and dynamic analysis. The analytical models are the beam(H-294x200x8x12) and column(H-200x200x8x12). As the result, a thick plate element is most efficient for blast analysis. Through this way, blast and collapse analysis are simulated with the imaginary steel frame.

강성변화를 고려한 점용접부의 준정적 및 진동피로해석

이동철(Dong-Cheol Lee),강기원(Ki-weon Kang) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12

The purpose of this paper was to evaluate the fatigue life to apply the vibration fatigue analysis and quasi-static methods, considering the stiffness change of the spot weld. first this material acquire the tensile and fatigue properties of the spot weld and tensile properties of the base metal material. In particular, by applying the finite element method to obtain the S-N curve. It was applied to fatigue analysis each condition. By performing a linear static analysis was to understand the vulnerable part. Acquire to the fatigue properties of the spot weld, take the load history of the three levels in the time domain, was performed by setting as a condition of quasi-static fatigue analysis. The process of the vibration fatigue analysis was after the frequency response analysis, gain transfer function of the structure was carried out by selecting the PSD of the three levels in the frequency domain. Fatigue life prediction method of the spot weld was by applying the method according to the fatigue damage accumulation and the conventional method was compared analyzed with the results shown.

동적 환경에 노출된 전자유닛의 과도응답해석과 준정적해석에 관한 비교연구

전호일(Ho Il Jeon),박기철(Gi Chul Park) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12

When analyze the system exposed to the dynamic environment, there are several cases to use the quasistatic analysis method. Because it can reduce the time of analysis remarkably and simplify the solution of analytical model. So the quasi-static analysis is used to be the one of the alternative method for solving the dynamic analysis problem efficiently. In the study, the structural characteristics of system using the transient response analysis and the quasi-static analysis is compared.

Fatigue Analysis of Vehicle Chassis Componet Considering Resonance Frequency

Lee, Sang Beom,Yim, Hong-Jae 한국공작기계학회 2004 한국생산제조학회지 Vol.13 No.6

The purpose of this paper is to assess the benefits of frequency domain fatigue analysis and compare it with more conventional time domain techniques. The multi-body dynamic analysis, FE analysis and fatigue life prediction technique are applied for the frequency domain fatigue analysis. To obtain the dynamic load history used in the frequency domain fatigue analysis, the computer simulations running over typical road profiles are carried out by utilizing vehicle dynamic model. The fatigue life estimation for the rear suspension system of small-sized passenger car is performed by using resonance durability analysis technique, and the estimation results are compared with the conventional quasi-static durability analysis results. For the pothole simulation, the percent changes of the fatigue life between the two durability analysis techniques don't exceed 10%. But, for the Belgian road simulation, because of the resonance effect, the fatigue life using the resonance durability analysis technique are much smaller estimated than the quasi-static durability analysis results.

6U급 초소형위성 HiREV의 구조 설계 및 해석

신한섭,김해동 항공우주시스템공학회 2018 항공우주시스템공학회지 Vol.12 No.3

한국항공우주연구원에서는 지구관측을 위한 고해상도 영상 및 이미지 촬영을 위해 6U급 초소형 위성HiREV를 개발하였다. 6U급 초소형 위성은 1U/3U급 초소형 위성에 비하여 부피가 크기 때문에 1차 고유 진동수가 상대적으로 낮으며, 구조적 하중에 의한 큰 응력과 변형량이 생길 수 있어 구조 해석을 통한 검증이 필요하다. 본 논문에서는 임무 탑재체를 탑재하고 구조적 문제점을 보완하기 위한 6U급HiREV 위성의 구조체 설계에 대해서 설명하였고 가속도 하중 해석, 모달 해석, 랜덤 진동 해석 등의구조 해석을 수행하였으며, 6U급 HiREV의 구조체 설계가 구조적으로 안정성 있게 설계되었음을 입증하였다. 이러한 결과들은 향후 국내에서 다양한 임무에 적용될 6U급 초소형 위성의 구조체 개발 시 유용한 참고자료가 될 것으로 사료된다. The Korea Aerospace Research Institute has developed a 6U HiREV Nano-satellite for the observation of the earth using high resolution videos and images. Since the 6U Nano-satellite is bulky compared to the 1U/3U Nano-satellite, the first natural frequency is relatively low. Large equivalent stress and total deformation, due to structural load, can be generated. In this paper, the design of the 6U HiREV Nano-satellite is described and structure analysis, such as acceleration load analysis, modal analysis, and random vibration analysis are carried out. It is proven that the structural design of the 6U HiREV is stable. These results will be useful as reference materials for the development of additional 6U Nano-satellites, which will be applied to various future missions in KOREA.

eVTOL 블레이드 피치 제어용 전기식 작동기의 준정적 내구해석 기반 피로수명 평가

김영철,김동협,김상우,이종환,강정현,김도형 한국항공우주학회 2023 韓國航空宇宙學會誌 Vol.51 No.5

The structural safety for the fatigue behavior of an electro-mechanical actuator for eVTOL blade pitch control was investigated. The load history of the actuator was calculated using the multi-body dynamics analysis. Furthermore, a static load analysis against the rated load was performed to determine a weak area and construct a stress spectrum for the weak area. A P-S-N curve was derived for conservative fatigue life evaluation, and a quasi-static durability analysis was performed by applying the constructed stress spectrum to the algebraic equation of the P-S-N curve. As a result, fatigue lives of over 10^7 cycles were calculated for all parts of the actuator, confirming structural safety for fatigue behavior. 본 연구에서는 eVTOL 블레이드 피치 제어용 전기식 작동기의 피로거동을 검토하였다. 다물체 동역학 해석을 통해 작동기의 하중이력을 산출하였다. 또한 정격하중에 대한 정하중 해석을 수행하여 취약 부위를 선정하고, 취약 부위의 응력 스펙트럼을 구축하였다. 이후 보수적인 피로수명 평가를 위해 P-S-N 선도를 작성하였고, 구축된 응력 스펙트럼을 P-S-N 선도의 대수방정식에 적용하여 준정적 내구 해석을 수행하였다. 해석 결과, 작동기의 모든 부품에 대해 10^7 cycles 이상의 피로수명이 산출되어 피로 거동에 대해 구조적으로 안전함을 확인하였다.

[기술논문] 분산 분석을 이용한 자동차 안전벨트 준정적 해석과 인장시험 상관성 개선

이광섭(Kwangseop Lee),어영우(Youngwoo Eo),김삼성(Samsung Kim),김두용(Dooyong Kim),송택림(Taeckrim Song),이경상(Kyeongsang Lee) 한국자동차공학회 2016 한국 자동차공학회논문집 Vol.24 No.3

This study makes a relative comparison of the results of tensile test and quasi-static analysis using AGL(Adjuster Guide Loop) model that plays a role in adjusting the height of shoulder belt, of the components of the vehicle seatbelt system and attempts to propose a method of reducing the error rate of the quasi-static analysis technique effectively. This study selects two major factors affecting the result of an analysis, draws the result of analysis through the method of experimental design, one of the statistical techniques and understands the contribution rate of the major factors affecting the result of the analysis through ANOVA(Analysis of Variance).

준정적해석을 통한 승용차용 등속조인트 부품의 접촉력 및 소성변형 분석

이형욱(Hyoungwook Lee),정준영(Jun Young Jeong),조호선(Hosun Cho),오병기(Byung-ki Oh) 한국자동차공학회 2021 한국 자동차공학회논문집 Vol.29 No.5

In evaluating the strength and behavior of a constant velocity joint for a compact drive shaft considering a quasi-static state, the analysis has been carried out with the plastic deformation behavior of a cage where the fracture is mainly reported. The analysis was conducted according to the actual experimental conditions by simultaneously imposing low rotational speed and torque that are in a quasi-static state. The elasto-plastic material properties were set to the cage. The cage rotates while making contact with balls, an outer race and an inner race. It was found that the effective plastic strain at each location of the cage increased in the form of a step, and the increased location was determined according to the phase angle. The plastic deformation position in the cage could be verified through the analysis of the contact force between the parts according to the phase angle representing the cylindrical coordinate system.