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윤도희(Do-hee Yoon) 항공우주시스템공학회 2024 항공우주시스템공학회지 Vol.18 No.2
인공위성은 발사체 모델과 연성하중해석을 수행하여 설계를 최종 검증하게 된다. 연성하중해석 결과의 정확도를 높이기 위해서는 유한요소모델 정확도가 매우 중요하며, 이를 위해 모델 보정은 필수적이다. 일반적으로 모델 보정은 재료 물성치와 두께 등을 하나씩 바꿔가며 수행하게 되는데, 이는 매우 많은 시간과 비용이 소요된다. 따라서 본 논문에서는 최적화 기법을 이용하여 탑재체 유한요소모델의 보정작업을 보다 효율적으로 수행하였다. 분산분석을 통해 중요 변수를 선정하고, 크리깅 대체 모델을 이용하여 해석과 최적화에 필요한 시간과 비용을 절감하였다. 본 논문에서 제안한 보정 방법은 진동 시험결과만 있으면 적용할 수 있으며, 수치적인 계산 비용과 소요 시간을 대폭 줄일 수 있다는 점에서 효율성 측면에서 큰 장점이 있다. A satellite is ultimately verified by performing a coupled load analysis with the launch vehicle. To increase the accuracy of the coupled load analysis results, it is important to have good accuracy of the finite element model. Therefore, finite element model correlation is essential. In general, model correlation is performed by changing the material properties and thickness one by one, but this process takes a lot of time and cost. The current paper proposes an efficient model correlation method using optimization. Significant variables were selected through analysis of variance, and the time and cost required for analysis and optimization were reduced by using the Kriging surrogate model. The method proposed in this paper can be applied only with the vibration test results, and it has a great advantage in terms of efficiency in that it can significantly reduce the numerical calculation cost and time required.
윤도희(Do-hee Yoon),서종은(Jong-Eun Suh),한재흥(Jae-Hung Han),서중보(Joongbo Seo),송덕기(Deok Ki Song) 한국소음진동공학회 2018 한국소음진동공학회 논문집 Vol.28 No.4
In this paper, a vibration isolator using a viscoelastic material is proposed for reducing the micro-vibration in satellite platforms. In order to describe the vibration isolator, a mathematical model is derived in six degrees of freedom: three translational and three rotational motions. Then, the mathematical expressions of the force and moment transmissibility, which can evaluate the amount of reduction in micro-vibration through the vibration isolator, are established. The proposed mathematical model for vibration isolator is verified by comparing the transmissibility plots obtained from the mathematical model and the ANSYS results. Finally, the effect of the design parameters on the isolation performance is investigated using the mathematical model.
윤도희(Do-hee Yoon),권성철(Seong-Cheol Kwon) 한국소음진동공학회 2020 한국소음진동공학회 논문집 Vol.30 No.6
In this study, a structural model was manufactured and a launch environment test was conducted to verify that the designed Electro-optical payload could withstand the launch environment. Two tests were conducted: random vibration test and shock test. In random vibration test, a notching was applied to prevent excessive dynamic loads on the structure by considering design load. Before and after conducting each test, a low-level sinusoidal sweep test was performed to confirm that there are no structural defects by examining the changes in the natural frequency and damping characteristics. Using this, the structural integrity of the Electro-optical payload for random vibration and shock tests could be verified. A limitation with the notching method, introduced in this paper, is that it is only applicable if the non-linearity of the structure can be ignored. However, there is a great advantage in terms of efficiency because this method can be applied without a prior structural analysis for notching.