This paper proposes the armored combat bulldozer, essential for amphibious tasks, requires water ingress prevention and submersion capabilities, typically addressed by a centrifugal pump. This study aims to boost the bulldozer's drainage pump efficiency by replacing the traditional aluminum 3-blade impeller with one made of ASA material using 3D printing. Analysis via ANSYS Fluent revealed that the 5-blade impeller increased discharge volume by 19.31% and efficiency by 6.07%, while the 6-blade variant saw a 27.07% increase in discharge volume and 8.81% efficiency improvement. Further scrutiny with ANSYS Static Structure ensured the new impellers' structural integrity and robustness under extreme conditions. This research confirms the potential of 3D printing in enhancing military equipment, demonstrating significant improvements in pump performance and opening paths for advanced manufacturing techniques to meet the demanding needs of combat vehicles.

In this paper, a structural design method of a smart tuned mass damper (TMD) for a retractable-roof spatial structure under earthquake excitation was proposed. For this purpose, a retractable-roof spatial structure was simplified to a single degree of freedom (SDOF) model. Dynamic characteristics of a retractable-roof spatial structure is changed based on opened or closed roof condition. This condition was considered in the numerical simulation. A magnetorheological (MR) damper was used to compose a smart TMD and a displacement based ground-hook control algorithm was used to control the smart TMD. The control effectiveness of a smart TMD under harmonic and earthquake excitation were evaluated in comparison with a conventional passive TMD. The vibration control robustness of a smart TMD and a passive TMD were compared along with the variation of natural period of a simplified structure. Dynamic responses of a smart TMD and passive TMD under resonant harmonic excitation and earthquake load were compared by varying mass ratio of TMD to total mass of the simplified structure. The design procedure proposed in this study is expected to be used for preliminary design of a smart TMD for a retractable-roof spatial structure.

초고층 건물의 구조설계시 풍하중에 의한 횡방향 변위를 적절한 값 이내로 줄이는 것이 가장 중요한 문제 중에 하나이다. 이를 위해서 추가적인 감쇠기 및 진동제어장치를 사용하는 방법이 일반적으로 고려되고 있다. 이 때 일반적으로 구조물의 특성은 변화없이 추가되는 제어장치에 대해서만 최적설계를 수행하게 된다. 본 연구에서는 구조물과 스마트 제어장치의 다목적 통합 최적화를 통하여 추가되는 스마트 제어장치로 인하여 구조물의 물량을 줄일 수 있는 가능성을 검토하였다. 이를 위하여 다이어그리드 구조시스템이 적용된 60층 초고층 건물을 예제 구조물로 선택하였고, 인공 풍하중에 대한 풍응답을 검토하였다. 스마트 제어장치로는 TMD에 MR 감쇠기를 설치한 스마트 TMD를 사용하였다. 구조물의 응답과 구조물량 및 제어장치의 용량을 동시에 줄이는 것이 필요하므로 본 연구에서는 다목적 유전자알고리즘을 적용하였다. 수치해석결과 제어성능목표를 만족시키면서 구조물의 물량과 제어장치의 용량을 적절하게 줄일 수 있는 다양한 설계 최적안을 얻을 수 있었다.

전단벽-골조 구조시스템의 구조적인 거동은 휨거동하는 전단벽과 전단거동하는 골조의 상호작용에 의하여 결정된다. 이러한 전단벽-골조 구조물의 거동특성을 효과적으로 고려하기 위하여 선행 연구에서는 2차원 T형 강체를 사용한 단순 해석 모델을 제안하였다. 본 논문에서는 이를 바탕으로 편심코어를 가진 전단벽-골조 구조물에 대한 효율적인 해석모델을 제안한다. 2차원 등가모델을 3차원으로 확장하여 비틀림 거동을 고려할 수 있도록 하였고, 그 결과 제안하는 등가모델이 편심코어를 가지는 전단벽-골조 구조물에도 적용가능 하도록 하였다.

본 연구에서는 고층 전단벽-골조 구조시스템의 효율적인 해석모델을 제안하였다. 전단벽-골조구조시스템은 휨거동하는 전단벽과 전단거동하는 골조로 구성된다. 그리고 전단벽-골조구조시스템의 변형형상은 골조와 전단벽의 상호작용으로 결정된다. 효율적인 해석모델에서는 이러한 거동특성을 반영되어야 하므로 골조와 전단벽을 분리하여 동적인 거동특성을 반영할 필요가 있다. 본 연구에서는 벽체부와 골조부를 분리하기 위하여 T형 강체를 전단벽의 위치에 대체하는 방법을 사용하였다. 분리한 벽체부와 골조부 각각의 등가모델을 구성한 후 결합시키는 방법으로 고층 전단벽-골조구조시스템의 등가모델을 완성하였다. 제안한 등가모델의 정확성과 효율성을 검증하기 위하여 고층의 전단벽-골조 구조물의 시간이력해석을 수행하였고, 그 결과 제안한 등가모델이 해석시간과 컴퓨터 메모리를 현저하게 줄이면서도 정확한 결과를 도출하였다.

The hollow slab has advantages that its self-weight does not greatly increase notwithstanding the increase of its thickness and its flexural performance does not significantly degrade in comparison with general reinforced concrete slab. However, the utilization of the hollow slab is currently being underestimated in spite of structural system that enables economic design of building and construction of eco-friendly structure. the significant reasons for this situation is that the method of structural analysis and design for hollow slab is not generalized. In this study, to consider practical compressive zone of hollow slab, the equation for its flexural strength is proposed by the volume of compressive stress block according to neutral axis location in hollow section assumed. Existing estimation method of flexural strength of hollow slab considering only compressive zone above hollow part is evaluated as the most conservative method and the method estimating flexural strength by two alternative cross-section of hollow slab is evaluated as more practical method.

In order to reduce seismic responses of a structure, additional dampers and vibration control devices are generally considered. Usually, control performance of additional devices are investigated for optimal design without variation of characteristics of a structure. In this study, multi-objective integrated optimization of structure-smart control device is conducted and possibility of reduction of structural resources of a building structure with smart top-story isolation system has been investigated. To this end, 20-story example building structure was selected and an MR damper and low damping elastomeric bearings were used to compose a smart base isolation system. Artificial earthquakes generated based on design spectrum of low-to-moderate seismicity regions are used for structural analyses. Based on numerical simulation results, it has been shown that a smart top-story isolation system can effectively reduce both structural responses and isolation story drifts of the building structure in low-to-moderate seismicity regions. The integrated optimal design method proposed in this study can provide various optimal designs that presents good control performance by appropriately reducing the amount of structural material and damping device.

Japonica rice cultivars exhibit high susceptibility to bacterial blight(BB) disease due to genetic vulnerability in Korea. Korean japonica resistant rice cultivars mainly possess one of the genes, Xa1 or Xa3 for BB resistance. These resistance genes are becoming susceptible to K3a, resulting in serious rice yield reduction. This study was carried out to confirm the effect of xa13 gene pyramiding for developing of japonica rice cultivars resistant to BB pathogen breaking down Xa1 or Xa3. IRBB4 conferring Xa4 gene was resistant to K1(HB01013), K2(HB01014), K3(HB01015), and moderately resistant to K3a(HB01009). IRBB5 having xa5 gene was resistant to K1, K2, K3, and K3a. The recessive gene xa13 was resistant to K1 race but susceptible to K2, K3, and K3a. But Xa21 gene is susceptible to predominant K1 race but resistant to other races such as K2, K3, and K3a. Two genes Xa3 and xa13 were susceptible and Xa4 gene was moderate resistant to 24 isolates. xa5 and Xa21 genes were resistant to all isolates including K3a. When xa13 gene combined Xa4, xa5 and Xa21 genes, effect of xa13 gene pyramiding showed higher resistant reaction than that having singe gene out of Xa4, xa5, and Xa21. The order of resistance against 24 isolates breaking down Xa3 gene was IRBB55(xa13+Xa21) > IRBB53 (xa5+xa13) > IRBB51 (Xa4+xa13).