• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3766-3777
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• 2022

It is essential to ensure the safety of spent nuclear fuel (SNF) transport cask in drop situation that is included in transport accident scenarios. The safety of the drop situation is affected by the impact absorption performance of impact limiters. Therefore, when designing an impact limiter, the uncertainty in the material properties that affect the impact absorption performance must be considered. In this study, the material properties of the wood inside the impact limiter were selected as the variables for a parametric study. The sensitivity analysis of the drop response of the SNF transport cask with impact limiter was performed. The minimum wood strength required to prevent a direct collision between the cask and floor was derived from the analysis results. In addition, the plastic strain response was analyzed and strain-based evaluation was performed. Based on this result, the critical values of wood properties that change the impact dynamic characteristics were investigated. Finally, the optimal material properties of wood were obtained to secure the structural safety of the SNF transport cask. The results of this study can contribute to the development of SNF transport cask, thereby ensuring safety in transport accident conditions.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Proceedings of Pre-symposium of the 10th ISWPC
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• pp.9-18
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• 1999

Recycling systems are usually designed with pulp quality targets based on cleanliness, or similar property. Achieving other specific fibre properties is rarely a goal of a recycling system, but fibre properties can be modified to suit specific end uses. Recycling line equipment choices impact n fibre properties, but these effects choices impact on fibre properties, but these effects tend to be less well documented than the effects on cleanliness or brightness.

• International Journal of Automotive Technology
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• 제7권3호
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• pp.337-343
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• 2006

Numerical calculations are made in order to find a possible correlation between the J-integral and the crack mouth opening displacement(CMOD) in dynamic nonlinear fracture experiments of 3-point bend(3PB) specimens. Both elastic-plastic and elastic-viscoplastic materials are considered at different impact velocities. The J-integral may be estimated from the crack mouth opening displacement which can be measured directly from photographs taken during dynamic experiments.

• 벤처창업연구
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• 제14권5호
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• pp.1-11
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• 2019

스타트업의 생존 및 성장에 있어서 자금조달은 매우 중요한 역할을 한다. 이 연구에서는 스타트업의 자금조달 성과를 향상시키는 주요 요인을 탐구한다. 이를 위해 스타트업의 지식재산 보유수준과 자금조달 성과의 관계를 분석한다. 또한 스타트업의 자금조달에 있어서 창업자 지식수준이 미치는 영향을 확인하며, 스타트업의 지식재산 비중과 자금조달의 관계에 대한 창업자 지식수준의 조절적 영향을 분석한다. 국내 창업자 및 예비창업자 331명의 설문조사 응답 데이터를 기반으로 분석한 결과, 스타트업의 지식재산 비중과 자금조달 성과 사이에는 역 U자형의 비선형 관계가 존재한다는 점을 발견했다. 창업자의 학력은 자금조달 성과에 정(+)의 영향을 미치지만, 창업자 학력은 스타트업의 지식재산 비중과 자금조달 성과의 관계를 음(-)의 방향으로 조절하는 것으로 나타났다. 이러한 연구는 스타트업의 자금조달 성과를 극대화하기 위해서는 적절한 수준의 지식재산 비중을 유지하는 게 필요함을 시사한다. 또한 창업자가 고학력자일수록 자금조달에 유리하지만, 창업자의 학력은 스타트업의 자금조달에 대한 지식재산의 효과를 감소시키기 때문에 창업자의 지식수준에 따라 지식재산 비중을 차별적으로 조절하는 전략이 필요함을 시사한다. 이 연구는 신호이론에 기반하여 스타트업의 자금조달 성과를 높이기 위한 새로운 지식재산 전략을 제시한다는 점에서 의의를 지닌다.

• 한국산학기술학회논문지
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• 제15권7호
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• pp.4081-4086
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• 2014

CAB는 광학적 특성이 우수한 생분해성 수지이나 취약한 가공성으로 인해 필름 어플리케이션에 제한되어 있다. 본 실험에서는 비교적 가공성이 우수한 폴리락틱산을 이용하여 CAB의 가공성을 향상시키고, 충격보강제 도입으로 기계적 물성을 보완하고자 하였다. 이전 실험에서 PLA/CAB binary 블렌드의 PLA75CAB25조성이 상용성을 보이는 것을 확인하였으므로 PLA75CAB25 조성에 한하여 충격보강 연구를 수행하였다. 이축압출기를 이용하여 충격보강제를 도입하고, $140^{\circ}C$(hopper)-$200^{\circ}C$(die)의 온도 범위에서 200rpm의 속도로 제조하였다. 충격보강제 도입에 따른 상용성을 평가하기 위해 DSC와 FE-SEM을 통해 유리전이온도 거동과 모폴로지를 관찰하였다. 또한 충격보강효과를 확인하기 위해 DMA와 Izod 충격강도 시험기를 이용하여 저장탄성률과 충격강도를 측정하였다. 충격보강제가 10wt%가 도입되었을 때 상용성이 가장 좋았으며, Izod 충격강도가 PLA75CAB25 조성에 비해 4배 이상 향상되었음을 확인하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.490-494
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• 2008

U-Channel Bridge is effective bridge type, because its edge beam performs role of barrier and enables to reduce additional dead loads. Although it is effective to reduce additional dead loads, there is possibility of bridge collapse under impact load due to car crash. Also, edge beam must have ability to induce safe driving and prevent falling accidents. Therefore, it requires behavior analysis and property investigation through the vehicle impact crashing edge beam. This study presents method of structural analysis of U-channel bridge and investigates design specifications for the effect of the edge beam under the vehicle impact. Also, it carries out stability investigation of behavior of edge beam and slab, based on Korean Highway Bridge Design Specifications and AASHTO LRFD Bridge Design Specification.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.97-100
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• 2002

In this research, the impact behavior of the boundary between MMC-reinforced SiC whisker and Al alloy were studied. It is known that the resultant of the interfacial reaction between SiC whisker and Al alloy has brittle and low toughness property. In this paper, impact behavior of graded MMC & Al alloy shows the interfacial opening at the boundary. Generally this phenomenon is generated by thermal residual stress, brittle interfacial reaction resultant and difference of the deflection. So, these results may be interpreted as a macroscopic method of measuring the interfacial strength between matrix and reinforcement

• 한국기계가공학회지
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• 제10권1호
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• pp.38-46
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• 2011

A study was performed to investigate the dynamic behaviors of fiber-reinforced composite materials subjected to transversely low-velocity impact. For this purpose, the simulation of modified beam finite element based on higher order beam theory for two(isotropic and anisotropic) materials is carried out according to the changes of material property, stacking sequence, geometric dimension and impact velocity of steel ball, etc. Main composite materials for simulation are composed of $[0^{\circ}/90^{\circ}/0^{\circ}/-90^{\circ}/0^{\circ}]_{2s}$, $[0^{\circ}/90^{\circ}/0^{\circ}/-90^{\circ}/0^{\circ}]_s$ and $[0^{\circ}/45^{\circ}/0^{\circ}/-45^{\circ}/0^{\circ}]_{2s}$, $[0^{\circ}/45^{\circ}/0^{\circ}/-45^{\circ}/0^{\circ}]_s$ stacking sequences. The effectiveness of this simulation for qualitative and quantitative evaluations in composite materials subjected to foreign object impact was established.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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• pp.171-174
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• 2004

In order to improve the damage tolerance of the conventional laminated composites, three­dimensional fiber structures incorporated with stitching yams have been utilized in this study. From the newly developed process termed as TAPIS(TApe Placement Incorporated with Stitching), carbon/epoxy composites have been fabricated. Two-dimensional composites with the same stacking sequence as 3D counterparts have also been fabricated for the property comparison. To examine the damage resistance performance the low speed drop weight impact test has been adopted. For the assessment of damage after the impact loading, specimens were subjected to C-scan nondestructive inspection compression after impact(CAI) were also conducted to evaluate residual compressive strength. Although the damage area of 3D composites was greatly reduced$(30-40\%)$ compared with that of 2D composites, the CAI strength did not show drastic improvement.

• International Journal of Korean Welding Society
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• 제3권2호
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• pp.1-6
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• 2003

The abrasion and impact wear resistance were investigated on the hardfacing weld dispersed with the recycled hard metal(HM). The HM was composed of the tungsten carbide(WC) reinforced metal matrix composite. The cored wire filled with the 35 wt.％ HM and 0­6 wt.％ of the alloying element, Fe­75Mn­7C(FeMnC), was used for the gas metal arc(GMA) welding. The FeMnC addition to the 35 wt.％ HM did not improve the abrasion wear property since the amount of the tungsten carbide formed was decreased with respect to the FeMnC amount. However, the 6 wt.％ FeMnC addition to the 35 wt.％ HM exhibited the better impact wear resistance than the hardfacing weld by the 40 wt.％ HM.