Earticle

본 연구는 우리나라 발전시장의 계통한계가격(SMP) 하향 안정화를 위한 시사점을 도출하고자 SMP의 결정요인과 변동성 변화를 분석하였다. SVAR모형으로 구조충격을 식별하고, 이를 SMP증가율에 대해 표현한 후 구조변화 분석방법으로 SMP의 변동성 변화를 분석하였다. 2001～2014년까지의 월별자료를 이용하여 실증 분석한 결과, SMP 변동성은 발전공급능력, 첨두부하 비중, 첨두부하의 연료가격 등에 영향을 받는 것으로 나타났다. 또한, 2009년 10월 이후로 전력수요예측모형의 예측오차와 전력예비율에서 발생하는 전력수요 예측오차가 SMP 변동성의 새로운 결정요인인 것으로 확인되었고 그 경로는 첨두부하 비중인 것으로 나타났다. 본 연구의 실증결과는 장기적으로 연료가격이 낮은 발전소를 확대하는 것과 함께, 전력수요 예측모형의 예측력 제고와 적정 전력 예비율 설정을 통해서 전력수요 예측오차를 5% 이내로 유지한다면 SMP의 하향 안정화를 달성하는데 도움이 됨을 시사한다.

This paper analyzes system marginal price(SMP) volatility in Korea. Using SVAR, we first identified structural shocks, and applied structural break analysis to investigate the volatility of SMP. Empirical results show that the determinants of SMP volatility are power supply capacity, the ratio of peak load power and the fuel price of peak load power. Additionally, we find that the new important factor of leading SMP volatility to change is electricity demand forecast error shocks. Therefore, it is implied that maintaining the appropriate level of electricity demand forecast error is helpful for SMP volatility stabilization with increasing power stations of low fuel price.

Performed here is a comparative assessment study for the probabilistic fracture mechanics approach of the pressurized thermal shock of the reactor pressure vessel. A round robin consisting of one prerequisite deterministic study and five cases for probabilistic approaches is proposed, and all organizations interested are invited. The problems are solved by the participants and their results are compared to issue some recommendation of best practices and to assure an understanding of the key parameters in this type of approach, like transient description and frequency, material properties, defect type and distribution, fracture mechanics methodology etc., which will be useful in the justification through a probabilistic approach for the case of a plant over-passing the screening criteria. Six participants from 3 organizations responded to the problem and their results are compiled and analyzed in this study.

본 연구는 한국의 24개 분기별 거시시계열 자료를 대상으로 경제구조 변화가 단위근 검정과 지속성 측정에 미치는 효과를 검토한다. 우선, 단위근 검정과 정상성 검정을 수행하면서 최대 두 번의 구조변화를 허용한 결과 한국의 많은 거시시계열 자료들도 분절-추세 정상 시계열에 가까운 것으로 나타났다. 특히, 1997-98년의 경제위기가 대다수 변수들의 움직임에 중대한 영향을 미쳤음을 확인할 수 있었다. 아울러, 이 같은 구조변화를 고려하면 최대자기회귀근과 자기회귀계수합, 충격효과의 반감기간을 이용하여 측정한 지속성의 크기 역시 상당히 낮아지는 것으로 나타났다. 본 논문에서는 실업률과 실질이자율, 실질환율의 경우를 예로 들어 새로운 실증결과가 어떠한 이론적 의의를 갖는지를 설명한다.

This paper investigates the effects of structural breaks on unit root tests and the measures of shock persistence using the Korean quarterly time series data. In addition to the standard unit root and stationarity test for the no-break case, we implement several recent unit root and stationarity tests allowing for up to two structural breaks. We find that a lot of Korean macroeconomic time series are characterized as broken-trend stationary. The dates of structural breaks in most cases point to the 1997 financial crisis. When the structural breaks are incorporated, we also find that the measured persistence falls dramatically for most of the series.

본 연구에서는 무릎 굽힘각도와 완충재사이의 상관관계를 통해 올바른 걸음걸이의 중요성과 완충재 의 마모에 관해 해석하였다. 완충재에 가해지는 등가응력의 분포형상을 볼 때, 그 마모의 정도를 유추할 수 있어 이를 통하여 인공관절 상, 하부 파트의 설계와 인공관절 착용자의 바른 자세를 유도할 근거를 제 시할 수 있다. 본 연구를 통하여 얻어진 무릎관절의 역학적 메커니즘과 인공관절을 삽입했을 때 나타나는 메커니즘에 대한 구조 해석 결과를 적용하여 무릎관절에 가해지는 피해량에 대하여 해석할 수 있다. 또한 실제 시험을 위해 예비된 시뮬레이션 해석 결과로서 실제의 생체실험에 대한 기초연구 자료로 제공될 수 있으며 그 실험과의 비교 분석 자료로도 사용할 수 있을 것으로 사료된다.

A visualization study of shock formation of the supersonic jet nozzle using a Shadowgraph Method (SM) was carried out to investigate the effect of the longitudinal variation of coaxial pipe end tip position inside the supersonic nozzle. The experiment was performed for the Mach number range from 1.1 to 1.2 at nozzle exit. The well known shock cell structure was shown with the pipe end located deep inside the nozzle for the studied Mach number. With the pipe end approaches nozzle exit, it was found that the shock cell structure disappeared and turned into complex formation. In order to understand the mechanism of the shock structural change, computational simulation was carried out using the Navier-Stokes solver, FLUENT. Topological sketch was added with an aid of the visualization and the numerical simulation.

Cold shock proteins (CSPs) are a family of proteins induced at low temperatures. CSPs bind to single-stranded nucleic acids through the ribonucleoprotein 1 and 2 (RNP 1 and 2) binding motifs. CSPs play an essential role in cold adaptation by regulating transcription and translation via molecular chaperones. The solution nuclear magnetic resonance (NMR) or X-ray crystal structures of several CSPs from various microorganisms have been determined, but structural characteristics of psychrophilic CSPs have not been studied. Therefore, we optimized the purification process to obtain highly pure Lm-Csp and determined the three-dimensional structure model of Lm-Csp by comparative homology modeling using MODELLER on the basis of the solution NMR structure of Bs-CspB. Lm-Csp consists of a ${\beta}$-barrel structure, which includes antiparallel ${\beta}$ strands (G4-N10, F15-I18, V26-H29, A46-D50, and P58-Q64). The template protein, Bs-CspB, shares a similar ${\beta}$ sheet structure and an identical chain fold to Lm-Csp. However, the sheets in Lm-Csp were much shorter than those of Bs-CspB. The Lm-Csp side chains, E2 and R20 form a salt bridge, thus, stabilizing the Lm-Csp structure. To evaluate the contribution of this ionic interaction as well as that of the hydrophobic patch on protein stability, we investigated the secondary structures of wild type and mutant protein (W8, F15, and R20) of Lm-Csp using circular dichroism (CD) spectroscopy. The results showed that solvent-exposed aromatic side chains as well as residues participating in ionic interactions are very important for structural stability. Further studies on the three-dimensional structure and dynamics of Lm-Csp using NMR spectroscopy are required.

Consider a failure model for a stochastic system. A shock is any perturbation to the system which causes a random amount of damage to the system. Any of the shocks can cause the system to fail at shock times. The amount of damage at each shock is a function of the sum of the magnitudes of damage caused from all previous shocks. The times between shocks form a sequence of independent and identically distributed random variables. The system must be replaced upon failure at some cost but it also can be replaced before failure at a lower cost. The long term expected cost per unit time criterion is used. Structural relationships of the optimal replacement policy under the appropriate regularity conditions will be developed. And these relationships will provide theoretical background for the algorithm development.

This study introduces an innovative approach for the rapid prediction of shock spectrum in ship structures subjected to underwater far-field explosion loads. A nine-compartment ship model is developed, with 31 test condition sets designed. For each set, sample measurement points are strategically placed at typical locations across various deck levels and on the inner and outer bottoms of the double bottom at different frame cross-sections. Shock spectrum (including spectral velocity, acceleration, and displacement) are extracted from these sample points to establish a comprehensive shock spectrum database. Using the Kolmogorov-Arnold Network, a rapid prediction model for ship structure shock spectrum is developed. The network's inputs include ship structural formal parameters (e.g., number and position of decks, transverse and longitudinal bulkheads), impact factors, feature transfer distances, and local shock factors. Spectral velocity, acceleration, and displacement are used as the network's outputs during training. A comparative analysis of prediction accuracy among the Kolmogorov-Arnold Network, Backpropagation Network, and Convolutional Neural Network is conducted. The results demonstrate that the Kolmogorov-Arnold Network exhibits superior predictive accuracy compared to the Backpropagation and Convolutional Neural Networks. In contrast to existing finite element simulation methods, the proposed approach is simpler and more practical. Furthermore, unlike current rapid prediction methods, the proposed method takes into account the influence of ship structural characteristics on underwater explosion shock responses, making it better suited to the requirements for rapid prediction of underwater far-field explosion shock spectrum in ship structures.

A probabilistic integrity analysis method is presented for a reactor vessel under pressurized thermal shock(PTS) based on Monte Carlo simulation. This method can be applied to the structural integrity assessment of a reactor vessel subjected to pressurized thermal shock where the coolant temperature transient cannot be expressed explicitly as a time function. An axially or circumferentially oriented infinite length surface crack is assumed to be in the beltline weld region of the rector vessel's inside surface. The random variables are the initial crack depth, neutron fluence on the vessel's inside surface, the copper and nickel content of the vessel materials, R $T_{NDT}$ , $K_{IC}$ , and K/aub la/. The reliability of a sample reactor vessel under PTS is assessed quantitatively and the influence of the amount of neutron fluence is also examined by applying the present method.sent method.

본 연구는 이질적 경제주체 뉴케인지언(HANK) 모형을 한국 경제에 적용해 IMF 외환위기, 글로벌 금융위기, 코로나19 팬데믹 시기의 소득분배 동학을 구조적으로 분석한다. 세전소득 지니계수와 상위 10% 소득집중도를 함께 분석함으로써 동일한 구조적 충격이 소득분포의 서로 다른 부분에 이질적인 영향을 미칠 수 있음을 보인다. 분석 결과에 따르면 총요소생산성 충격과 정부부채 충격은 두 지표를 반대 방향으로 움직이는 비동조 충격이며, 위험프리미엄·마크업·소득위험 충격은 두 지표를 같은 방향으로 움직이는 동조 충격이다. 역사적 충격분해에서는 위기마다 각 충격의 상대적 영향력이 달라지면서 서로 다른 분배 패턴이 나타났다. IMF 위기에는 지니계수가 상승하고 상위 집중도는 하락하는 비동조가, 글로벌 금융위기에는 비동조 충격과 동조 충격이 상쇄되면서 약한 비동조가, 코로나19에는 두 지표가 함께 상승하는 동조가 관찰된다. 세 위기 모두에서 저소득 가계에 대한 충격 노출이 지니계수의 상승 또는 높은 수준의 지속에 중요한 역할을 하였다.

This paper studies the asymmetric dynamics of income distribution during Korea’s three major economic crises through the lens of a heterogeneous-agent New Keynesian (HANK) model. We focus on the 1997 IMF crisis, the global financial crisis, and the COVID-19 pandemic, and jointly examine the pre-tax income Gini coefficient and the top 10 percent income share. This joint perspective shows that the same structural shock can affect different dimensions of the income distribution in different ways. Total factor productivity and government debt shocks move the two distributional indicators in opposite directions, whereas risk premium, markup, and income risk shocks move them in the same direction. Across crises, the relative importance of these shocks differs, producing distinct distributional patterns. The IMF crisis exhibits an opposite-direction pattern, with a rising Gini coefficient and a falling top income share. The global financial crisis shows a weaker version of this pattern, as same-direction and opposite-direction shocks partly offset one another. In contrast, the COVID-19 pandemic displays a same-direction pattern, with both indicators rising simultaneously. Across all three crises, greater exposure of low-income households to adverse shocks generates upward pressure on the Gini coefficient or helps sustain it at an elevated level.

노키아는 1990년대 북유럽 특유의 경쟁적 환경과 신기술에 대한 과감한 투자, 생산네트워크의 국제화에 힘입어 비약적으로 발전하였다. 전성기의 노키아는 전 세계 휴대폰 시장의 40%를 점유하였고, 핀란드 GDP의 20%에 달하는 매출을 기록하면서 핀란드 총수출의 20% 이상을 담당하였다. 노키아의 발전과 함께 핀란드 경제는 1993~2007년의 기간 중 연평균 4%의 고성장을 기록할 수 있었다. 그러나 한 기업에 지나치게 의존적인 산업구조는 핀란드 경제의 취약점으로 지적되었다. 2000년대 중반 이후 정보통신 산업계의 비즈니스 환경이 급변하고, 기업 간의 경쟁이 격화되면서 노키아의 매출은 급감하기 시작했다. 노키아는 생산과 고용에 있어 대규모의 구조조정을 단행하였으며, 2013년에는 결국 휴대폰 부문을 마이크로소프트에 매각하게 되었다. 노키아의 쇠퇴로 인해 전자통신 부문의 생산과 수출이 급감하면서 핀란드 경제에 큰 변화를 겪었다. 핀란드 경제가 장기침체를 겪고 있는 데에는 과거의 노키아를 대체할 수입창출 기업이 존재하지 않기 때문이다. 노키아의 쇠퇴는 핀란드 경제의 하방요인으로 작용하였으나, 창업분위기와 중소기업 지원체계에 있어 큰 변화의 계기로 작용하였다. 특히 노키아의 수많은 연구인력 및 중간관리자는 이후 핀란드의 창업확산에 큰 기여를 하고 있다. 한국은 수출의존도가 높다는 점, 대기업 위주의 산업생태계와 수출구조를 갖고 있다는 점에서 핀란드와 유사점이 있다. 노키아의 사례는 시장의 변화를 감지한 혁신의 필요성, 대기업-중소기업 간의 상생적 관계정립, 창업지원체계 등에 있어서 좋은 시사점을 제공해 준다.

Once diversified firm over a variety of production line, Nokia transformed itself to highly specialized firm in communication equipment, particularly mobile phone in early 1990s. Since then, Nokia expanded its production line in global scale and became leading firms, supplying 40% of world's mobile phone. At peak time, Nokia's turnover reached almost 20% of Finnish GDP and its export accounted for 20% of total export of Finland. Nokia contributed much to the growth of Finish economy which had enjoyed 4% of annual growth rate between 1993 and 2007. However, Finnish economy became too much dependent on the single firms and this was criticized as a fragile aspect of Finnish economy. Nokia's business began to suffer from mid 2000s amid the emergence of new products such as smart phone and increasingly intense competition in global market. Since the global financial crisis, its sales dropped in unprecedented scale and it became inevitable to restructure its production lines as well as reduce overall size of its personnel. Nokia finally sold its mobile phone device and services business to Microsoft in 2013. Nokia's fall, termed 'Nokia shock' dramatically affected Finish economy and caused the adjustment of Finnish industrial structure. Finland had economic recession for four consecutive years and main reason for this relatively long recession is that there is no alternative firms which can replace the roles of Nokia in Finnish economy. However, Nokia's fall has brought about some positive change such as rising startup in Finnland. Many former researchers of Nokia were directly involved into this boom of startup and industrial eco-system became more balanced between large firms and SMEs. Korea shares common features with Finland in that it has large export sectors and largely driven by conglomerates. In this regards, Nokia's rise and fall provide meaningful implication to discuss industrial relations in Korea.

The reversal of the growing trend of China’s current account surplus has drawn the attention from various fields since US sub-prime lending crisis. By adopting the industry-level trade data, the paper reveals the industrial structural feature of China’s current account surplus. Further, the paper figures out firms’ leading forces in each industry by using the firm-level trade data. The results show: (1) Labor-intensive industries are the main sources of China’s trade surplus while the foreign exchange-earning ability of technology-intensive industries is still relatively weak. (2) In most industries, trade surplus is mainly attributed to the quantity-expansion effect of existing products, and the effect of industrial upgrading out of high-tech enterprises and new products are negligible. (3) The quantity-expansion effect drives the rapid recovery growth of China’s trade surplus after the 2008 global financial crisis, and it can be properly inferred that the adjustment of China’s current account structure should be attributed to Chinese economy structural transformation other than crisis shock.

본 연구는 구조변화를 고려하여 대기업과 중소기업을 중심으로 우리나라 제조업 생산과 유가충격 간의 관계를 분석하였다. 내생적 구조변화 분석방법을 적용하여 산업생산과 유가충격 간의 관계를 살펴보았다. 1995년 1월부터 2013년 12월까지의 월별 자료를 이용하여 분석한 결과 생산과 유가충격 간의 관계에 구조변화가 발생한 것으로 확인되었다. 전체 제조업과 대기업 생산은 유가충격과의 비선형 관계가 구조변화 시점 이후로 사라졌으나 중소기업은 비선형 관계가 오히려 강화되었다. 구조변화 시점은 전체 제조업과 대기업은 2008년, 중소기업은 2005년으로 나타나 글로벌 경제충격들이 우리나라 제조업 생산과 유가충격 간의 관계를 변화시킨 것으로 나타났다. 또한 유가상승충격뿐만 아니라 유가하락충격도 우리나라 제조업 생산에 유의한 영향을 주는 것으로 나타났고, 비대칭적 유가충격 효과의 구조변화 발생시점은 2006년으로 추정되었다. 이와 같은 결과들은 1998년 외환위기와 같은 국내에서 발생한 경제충격들보다 글로벌 경제충격들이 우리나라 제조업 생산과 유가충격 간의 관계를 변화시킬 가능성이 높다는 것을 의미한다. 이는 생산에 대한 유가충격의 효과가 바뀔 수 있으므로 글로벌 경제충격으로 간주될 수 있는 사건들에 대해서 보다 더 관심을 가져야 된다는 것을 시사한다.

This study investigates the relationship between Korean manufacturing production and oil shock using structural break analysis methods. By empirical analysis, structural break between Korea manufacturing production and oil shock is confirmed. Nonlinear relationship between manufacturing production and oil shock has been weakened in total manufacturing and large business after structural break. But in the case of small business, nonlinear relationship between production and oil shock has been reinforced after structural break. It is estimated that structural break of total manufacturing and large business is year 2008 and that of small business is year 2005. Furthermore, not only oil increase shock but also oil decrease shock has an significant impact on Korean manufacturing production. It is estimated that the structural break of asymmetric oil shock effect on production is year 2006. These structural break analysis results imply that global economic shocks such as global financial crisis and the beginning of high oil price era can have more impacts on relationship between Korean manufacturing production and oil shock than domestic economic shocks.

Stress analysis and fatigue life on shock absorber are investigated in this study. The lower part of spring is shown with the maximum equivalent stress and displacement of 153.49MPa and 26.151mm. The rear part is also shown with the number of fatigue life less than $6.8241{\times}10^5$. And the middle part of spring is shown with the minimum safety factor of 0.94592. The designed modeling suspension in this study has no possibility with resonance. As the result of this study is applied by the chassis of automobile, the prevention on fatigue fracture and the durability is predicted.

본 연구는 2018년 미·중 무역갈등 격화가 동아시아 생산네트워크의 구조와 국내부가가치성과에 미친 영향을 분석하고, 충격 이후 생산망이 기존 경로로 복원(reversion)되었는지 여부를 검증한다. 2007–2023년 ADB 다지역 산업연관표를 활용하여 중국·일본·한국·대만·베트남의 제조업을 Lall(2000) 기준 5개 기술군(PP, RB, LT, MT, HT)으로 재구성하고, 전·후방평균전파길이(APL_F, APL_B)와 부가가치수출(VAX: JN, KWW)을 구축하였다. 이로써 기존 연구와 달리 본 연구는 생산망의 연결 방식과 가치성과를 결합해 충격의 지속성·비가역성을 산업별로 파악한다. 패널 단절 시계열(ITS) 분석 결과, 2018년은 ‘심화–성과 개선’ 연계가 약화되는 전환점으로나타났으며, 조정은 업스트림 조달보다 최종수요·수출과 인접한 다운스트림 연결에서 더 뚜렷했다. VAX는 충격 직후 단기 상승이 관측되었지만 사후 추세는 둔화되어, 생산망의 확장·심화가 자동적으로 가치포획을 보장하던 업그레이드 메커니즘이 약화될 가능성을 제기한다. 또한PP·RB·HT에서 수준 변화와 추세 둔화가 동반되는 선택적 조정이 확인되어, 재편은 전면적디커플링이라기보다 위험회피와 규제·통제의 비대칭이 결합된 부분적·다층적 재구성으로 해석된다. 정책적으로는 (1) 양적 확대 중심의 GVC 전략을 가치포획 역량의 내재화로 전환하고, (2) 회복탄력성의 초점을 조달 안정에서 수출시장·물류·규제 등 전방 리스크 관리로 확장하며, (3) 조기경보·컴플라이언스·역내 공조를 포함한 경제안보 대응 인프라를 제도화할 필요가있다.

This study examines how the escalation of the 2018 US?China trade conflict reshaped East Asia’s production networks and domestic value-added performance, and whether these networks reverted to their pre-shock trajectory. Using ADB multi-regional input?output (MRIO) tables for 2007?2023, we reclassify manufacturing industries in China, Japan, Korea, Taiwan, and Vietnam into five Lall (2000) technology groups (PP, RB, LT, MT, HT) and construct indicators of network structure?forward and backward average propagation lengths (APL_F, APL_B)?and value capture?value-added exports (VAX; Johnson?Noguera and Koopman?Wang?Wei). By linking connectivity and value-capture outcomes, the paper identifies the persistence and potential irreversibility of the shock at the industry level. Panel interrupted time-series (ITS) estimates show that 2018 marks a turning point: the pre-shock association between network deepening and improved VAX weakens thereafter. Adjustments are more pronounced in downstream linkages adjacent tofinal demand and exports than in upstream sourcing. VAX displays a short-run increase immediately after the shock, but its post-shock trend subsequently slows, suggesting that the traditional upgrading mechanism?whereby network expansion and deepening translated into domestic value capture ?has weakened. Evidence of selective adjustment is concentrated in PP, RB, and HT, where level shifts coincide with trend slowdowns, implying a partial, multi-layered restructuring driven by risk hedging and asymmetric regulatory pressures rather than uniform decoupling. Policy implications include shifting from volume-led GVC participation toward domestically embedded value-capture capabilities, extending resilience governance to downstream market/logistics/regulatory risks, and institutionalizing economic-security infrastructure through early-warning systems, compliance support, and regional coordination.

A series of shock wave pulses with Mach number 2.2 of 100, 200, and 300 shocks were applied to lead sulfide (PbS) nanomaterials at intervals of 5 sec per shock pulse. To investigate the crystallographic, electronic, and magnetic phase stabilities, powder X-ray diffractometry (XRD), diffused reflectance spectroscopy (DRS), and vibrating-sample magnetometry (VSM) were employed. The material exhibited a rock salt structure (NaCl-type structure); XRD results indicated that material is monoclinic with space group C121 (5). Further, XRD results showed shifts due to lattice contraction and expansion when material was subjected to shock wave pulses, indicating stable material structure. Based on the data obtained, we believe that the PbS material is a good choice for high-pressure, high-temperature, and aerospace applications due to its superior shock resistance characteristics.

최근 국내에서 육상 및 해상을 통한 소외 정상운반 시 진동 및 충격하중에 대한 사용후핵연료의 건전성 평가 기술 개발이 수행되고 있다. 이와 관련된 국내 연구사례는 전무하여 기존에 진행된 또는 현재 수행중인 해외연구사례를 조사하여 국내 연구에 참고하고자 한다. 2000년 이전 과거 미국의 사용후핵연료의 정상운반 시 진동 및 충격하중 측정 관련 연구현황을 조사하였고 2009년부터 미국국립연구소 주관으로 실시한 단축가진시험, 콘크리트블럭 트럭운반시험, 다축가진시험에 대해서 조사하였으며 2017년 미국 SNL, 스페인의 ENSA, 한국이 공동으로 수행한 복합운반시험을 상세히 조사하였다. 시험 준비과정, 절차, 가속도 및 변형률 측정결과, 유한요소 및 다물체동역학 해석과정 등이 조사되었다. 각 시험 별로 측정된 변형률 자료를 바탕으로 사용후핵연료 피로곡선과 비교한 결과 손상을 일으키기에는 매우 미미한 정도의 변형률이 발생한다는 초기 결론을 얻었음을 확인하였다. 하지만 현재 결론은 일부 결과만을 검토한 예비 결론으로 상세한 검토가 현재 미국에서 진행 중이다. 미국에서 지금까지 수행한 사용후핵연료의 정상운반조건에서의 진동 및 충격하중 측정과 관련하여 조사된 내용은, 국내 운반환경에서 사용후핵연료의 정상운반시험을 수행할 때 참고할만한 유용한 자료라 판단된다.

Currently, the development of evaluation technology for vibration and shock load characteristics and spent nuclear fuel structural integrity under normal conditions of transport is being conducted in the Republic of Korea. This is the first such research conducted in the Republic of Korea and, thus, previous international studies need to be investigated and will be referred to in the ongoing project. Before 2000, several studies related to measurement of vibration and shock loads on spent nuclear fuel were conducted in the US. US national research institutes conducted uniaxial fuel assembly shaker tests, concrete block tests, and multi-axis fuel assembly tests between 2009 and 2016. In 2017, multi-modal transportation tests including road, sea, and rail transport were also performed by research institutes from the US, Spain and the Republic of Korea. Therefore, test preparation procedures, acceleration and strain measurement results, and finite-element and multi-body dynamics analysis were investigated. Based on the measured strain data, the preliminary conclusion was obtained that the measured strain was too small to cause damage to spent nuclear fuel rods. However, this conclusion is a preliminary conclusion that only reviews part of the results; a detailed review is being conducted in the US. The investigation of international studies on spent nuclear fuel structural integrity tests considering vibration and shock loads under normal conditions of transport in the US will be useful data for the project being conducted in the Republic of Korea.

Nonlinear aeroelastic characteristics of a missile control surface are investigated in this study. The wing model has freeplay structural nonlinearity at its pitch axis. Nonlinear aerodynamic flows with unsteady shock waves are also considered in high-speed flow region. To effectively consider a freeplay structural nonlinearity, the fictitious mass method (FMM) is applied to structural vibration analysis based on finite element method (FEM). (omitted)

Nonlinear flow-induced vibration characteristics of a generic missile wing (or control surface) are investigated in this study. The wing model has freeplay structural nonlinearity at its pitch axis. Nonlinear aerodynamic flows with unsteady shock waves are considered in the transonic flow region. To practically consider the effects of freeplay structural nonlinearity, the fictitious mass method (FMM) is applied to structural vibration analysis based on a finite element method (FEM). A computational fluid dynamics (CFD) technique is used for computing the nonlinear unsteady aerodynamics of all-movable wings. The aerodynamic analysis is based on the efficient transonic small-disturbance aerodynamic equations of motion using the potential-flow theory. To solve the nonlinear aeroelastic governing equations including the freeplay effect, a modal-based computational structural dynamic (CSD) analysis technique based on fictitious mass method (FMM) is used in time-domain. In addition, CSD and unsteady CFD techniques are simultaneously coupled to give accurate computational results. Various aeroelastic computations have been performed for a generic missile wing model. Linear and nonlinear aeroelastic computations have been conducted and the characteristics of flow-induced vibration are introduced.

Two typical impact loadings, shock wave and gas bubble pulse, due to UNDEX(UNDerwater EXplosion), should be considered together for the closest response analysis of structure subjected to UNDEX to a reality. Since these two impact loadings have different response time bands, however, their response characteristics of structure are different from each other. It is impossible to consider these effectively under the current computational environment and the mathematical model has not yet been developed. Whereas Hicks model approximates the fluid-structure interaction due to gas bubble pulse as virtual mass effect, treating the flow by the response of gas bubble after shock wave as incompressible ideal fluid contrary to the compressible flow due to shock wave, Geers-Hunter model could make the closest response analysis of structure under UNDEX to a real one as a mathematical model considering the fluid-structure interaction due to shock wave and gas bubble pulse together using acoustic wave theory and DAA(Doubly Asymptotic Approximation). In this study, the application and effectiveness of integrated dynamic response analysis of submerged structure was examined with the analysis of the shock wave and gas bubble pulse together.