This study investigates the safety and life during the fatigue load by the configuration of seat frame. On back frame at seat frame, the life and damage are analyzed. The deformation and equivalent stress are compared with each other through the vibration analysis, The result of this study through the analysis can be applied to develop the automotive seat frame with durabilty and safety.
In this study, the fracture property of the bonded structure with aluminum foam is analyzed by using the closed aluminium foam for impact absorber. DCB and TDCB specimens manufactured with the single lap joint method of mode 3 are designed by varying the thickness. The static analysis through ANSYS finite element program is carried out on the specimen model due to each thickness. Also, the static experiment is performed in order to verify the analysis result. This study aims at comparing the shear strengths of the bonded structures of DCB and TDCB made with aluminum foam and investigating the mechanical properties.
The objective of this work is to investigate the A-IMS structural defects on the tubular shaft and solid shaft by analyzing the under-fill, metal flow, effective stress and load characteristics. The tubular shaft and solid shaft were designed 6 stage process by upper and lower die. The results were analysed by using a finite elements analysis method. The coefficient of frictions were set Oil_Cold conditions as referred to the analysis library. It was found that the actual under-fill phenomenon was not observed in both tubular and solid shaft. The load values of tubular and solid shaft were 520ton and 255ton, respectively. These values were under the limit of forging machine maximum value.
애멸구는 직접적인 흡즙과 식물병원성 바이러스 매개로 쌀 생산량 감소에 영향을 주는 주요 해충이다. 국내와 중국 집단의 유전자 구조를 미토콘드리아 마커를 기반으로 비교하였다. 국내 집단은 33개의 유전형으로 구성되어 있었고, 이 중에서 16개는 새롭게 밝혀졌다. 유전형과 뉴클로타이드의 변이는 각각 0.791-0.909와 0.0018-0.0029였으며, 지역 집단 간의 유전자 거리는 매우 낮았다(FST = -0.030~0.089). 국가 간 유전적 변이는 약 3.6%였으며, 덴드로그램 상에서는 3개의 그룹으로 구분이 되었다 (FCT = 0.201, P < 0.0001). 국내 집단은 7개 중국 집단과 그룹을 이루었는데, 해당 지역은 기존 문헌을 통해 밝혀진 비래 근원 지역을 포함하여 중국 내 이동 집단이 분포하는 지역인 것으로 밝혀졌다. 분자 생태학을 기반으로 한 집단 구조 연구는 비래 근원 추적 연구와 국내 집단에 미치는 영향을 이해하는데 중요한 정보를 제공해 줄 것이다.
Microstructure evolutions of thermosetting resin coating layers fabricated by electrostatic spray deposition (ESD) at various processing conditions were investigated. Two different typical polymer systems, a thermosetting phenol-formaldehyde resin and a thermoplastic polyvinylpyrrolidone (PVP), were employed for a comparative study. Precursor solutions of the phenol-formaldehyde resin and of the PVP were electro-sprayed on heated silicon substrates. Fundamental differences in the thermomechanical properties of the polymers resulted in distinct ways of microstructure evolution of the electro-sprayed polymer films. For the thermosetting polymer, phenol-formaldehyde resin, vertically aligned micro-rod structures developed when it was deposited by ESD under controlled processing conditions. Through extensive microstructure and thermal analyses, it was found that the vertically aligned micro-rod structures of phenol-formaldehyde resin were formed as a result of the rheological behavior of the thermosetting phenol-formaldehyde resin and the preferential landing phenomenon of the ESD method.
자의성을 둘러싼 논의에는 중지의 동기가 중심이 되고 있다. 물론 어떠한 행위에도 동기는 있다. 그러나 동기는 다의적이다. 또 반드시 하나의 동기에 의하여 행위가 행해지는 것도 아니다. 문제는 여러 가지 다수의 동기 중에서 행위를 중지시킨 요인을 어떠한 기준으로 추출할 것인가이다. 자의성의 일상언어적 의미는 외부적으로 강제되지 않는다는 것이다. 그렇다면 자의성의 존부에 우선 문제가 되어야 할 것은 중지행위에로 행위자를 강제하는 사정이 있는지 여부이다. 다음으로 그러한 외부적 상황이 행위자의 인식을 통하여 중지행위를 강제했다고 판단되면 자의성이 부정되고, 강제하지 않았다고 판단되면 자의성이 긍정된다. 여기에서 사용되는 것이 외부적 상황이 「일반적으로」 행위계속을 저지하는 강제적 요소가 될 수 있는가 하는 척도이다. 예컨대 단순한 시간의 경과는 강제적 요소의 판단에 척도가 될 수 없다. 이점에서 시사적인 것이 우리 판례에서 말하는 사회통념이다. 즉 일상생활상의 경험칙이라는 일반적 기준이다. 중지행위에로 행위자를 강제할 수 있는 외부적 상황인가는 통상적인 경험표준에 의하여 객관적으로 판단된다. 우리 판례도 이러한 사회통념을 기준으로 하지만, 판례가 사용하는 객관적 기준은 추상적으로 강제될 수 있는 외부적 사정이 존재한다는 것만으로 자의성을 부정한다는 점에 문제가 있다. 자의가 아니라고 말하기 위해서는 ‘행위자 자신에게도’ 그 강제가 기능하였다고 판단되어야 한다. 유혈을 보고 놀랐다는 사정이나 피해자가 애원하는 사정뿐만 아니라 발각될 위험이 있는 사태라고 하더라도 반드시 자의성을 부정하는 사정이라고는 할 수 없다. 이러한 사정이 일반적으로 자의성을 부정한다고 판단하고 더 이상의 판단을 하지 않음으로써, 결과적으로 판례는 자의성을 거의 인정하지 않는다. 중지행위의 자의성을 부정하기 위해서는 통상적인 경험에 비추어 일반적으로 강제가 될 수 있는 성질을 가지고, 이에 더하여 추가로 실제로도 행위자 자신에게 어쩔 수 없었다고 평가되어야 한다. 중지행위의 자의성을 부정하기 위해서는 통상적인 경험에 비추어 일반적으로 강제가 될 수 있는 성질을 가지고, 이에 더하여 추가로 실제로도 행위자 자신에게 어쩔 수 없었다고 평가되어야 한다. 이렇게 볼 때 요사이 유행하는 자의성에 대한 유형화작업은 그것이 무엇을 위한 유형화인지 관점을 갖지 않은 단순한 유형화이다. 그 결과는 원칙적 부정을 위한 유형화가 되고 만다. 이는 받아들일 수 없다. 유형화작업의 시각은 예외적 부정(예외적 긍정)을 위한 유형화여야만 한다.
이 연구는 법무부에서 시행하는 직업훈련 과정에 참여하는 수형자들을 대상으로 학습전이에 영향을 주는 요인이 무엇이며, 각각의 요인이 이에 미치는 직접적인 효과뿐만 아니라, 전이 요인간의 관계를 규명하고자 하였다. 그리하여 실제 교정시설에 직업훈련교육을 받고 있는 수형자를 연구대상으로 선정하고 설문조사를 실시한 결과는 다음과 같다. 첫째, 기술통계 분석결과 5점 척도의 중간 값인 3을 넘어서 수형자 직업훈련의 성과를 이루고 있다고 할 수 있다. 그리고 모든 변인에서 측정된 결과 값이 중간 값 이상으로서 수형자 직업훈련의 타당성과 책무성도 이루고 있다고 볼 수 있다. 둘째, 조직적 지원과 교육만족도가 중요한 변인으로 밝혀졌고, 본인들의 학습동기나 만족도와 같은 내생변인을 통하여 효과를 발생하는 것으로도 나타났다. 즉, 수형자들이 출소 후 배운 내용을 현업에 적용하기 위해서는 기관의 지원이 크게 작용하는 것으로 나타났다. 마지막으로 전이설계가 실제 현업과 유사한 학습 환경을 구성하여 훈련에서 습득한 내용 등을 활용하게 하고 전이를 촉진한다고 할 수 있다. 따라서 전이설계가 높을 때 학습전이가 잘 나타나는 것으로 결론지을 수 있다.
Thermographic imaging based non-destructive evaluation proceeds measuring the defect or internal condition of civil structures. To demonstrate the feasibility of the method, the infrared camera system is applied to various specimens. The technique described in this paper may allow us to find their numbers, locations, and the extent of damaged steels from the measurement in the long distance. In addition, a reinforced concrete specimens with different penetration depths is tested using the active thermography method, and to study the influence on the detecting internal rebar in cooled and heated conditions. The experimental results demonstrate that thermographic imaging method is useful for detecting the damage of steel structures and the unknown rebar in the concrete.
This paper dealt with the applicability of GFRP materials as reinforcements for a steel box girder bridge deck. The purpose of this study is to provide detailed design procedures with a code-based text for GFRP composites for civil engineering structures. From the example design, the deck was optimized from a serviceability perspective but was quite overdesigned with regard to flexural strength and creep rupture stress, due to its relatively low longitudinal modulus but high strength. We may conclude from these results that it is advisable to check the serviceability limits before optimizing the design for strength or starting the design from the serviceability calculation.
Bridge inspection structures are the structure which is installed on the piers, abutments, and copings for the inspection and maintenance of substructure. In this study, the structural performance of the bridge inspection structures using aluminum members manufactured by extrusion process is evaluated. The bridge inspection structures can be installed regardless of the shape of concrete surface through the simple cutting process. The structural performance of bridge inspection structures is evaluated using FE analysis. Moreover, experimental studies are conducted for the estimation of the structural safety of the members for the design load.
The proposed hybrid damper installs at a coupling beam and consists of a high-damping rubber (HDR) and steel pin. The proposed hybrid damper adopted a pin-lock system acts as a viscoelastic damper under wind load (small displacement) while it behaves as a hysteretic damper under earthquake load (large displacement).
In this paper, the pin-lock mechanism and structural performance of the proposed hybrid damper is evaluated through experiment. Experiments were carried out with the variables which displacement, loading frequency and steel pin quantities were used. Test results showed that the pin-lock mechanism and the performance of the hybrid damper under a large displacement were verified. Also equivalent damping ratios of HDR were increasing at a small displacement as displacement amplitudes were increasing. However HDR did not depend on frequency,
Determining of the shape in the process of design for natural draught cooling tower is very important, because the shape of hyperbolic shell is respond sensitively to dynamic behavior of the whole cooling tower against wind load. In engineering practice, the geometric parameters have been determining based on the natural frequency. This study analyses influence of the tower shell geometric parameters on the structural behavior. For three representative models were selected, they were analyzed based on evaluation of damage by means of nonlinear FE-method. As a result, a hyperbolic rotational shell with the small radius overall was the lowest damage index induced by sufficient capacity of the stress redistribution and thus a wind-insensitive structure.
This study analyze the dynamic response property of latticed domes according to natural frequency ratio of substructure. Through eigenvalue analysis, it is was confirmed that the half-open angle 30° and 45° dominate vibration mode of the vertical direction and the half-open angle 60° and 90° dominate vibration mode of the horizontal direction. Through the dynamic response analysis, it is was confirmed that the first frequency about total structure largely appears about the vertical and the horizontal direction regardless of half-open angle.
Cable network system is a flexible lightweight structure which curved cables can transmit only tensile forces. The weight of cable roof dramatically can reduce when the length becomes large. The cable network system is too flexible, most cable systems are stabilized by pretension forces. The tensile force of cable system is greatly influenced by the sag ratio and pretension forces. Determining initial sag ratio of cable roof system is essential in a design process of cable structures. Final sag ratio and pretension depends on initial installed sag and on proper handling during installation. The design shape of cable system has an affect on the sag and pretension, and must be determined using well-defined design philosophy. This paper is carried out the comparative data of the deflection and tensile forces on the geometric non-linear analysis of cable network systems according to sag ratio. The study of cable network system is provided to technical informations for the design of a large span cable roof, analytical results are compared with the results of other researchers. Structural nonlinear analysis of systems having cable elements is relatively complex than other rigid structural systems because displacements are large as a reason of flexibility, initial prestress is applied to cables in order to increase the rigidity, and then divergence of nonlinear analysis occurs rather frequently. Therefore, cable network systems do not exhibit a typical nonlinear behavior, iterative method that can handle geometric nonlinearities are necessary.
The Eradi Quake System (EQS) is a seismic isolation bearing system designed to minimize forces and displacements experienced by structures subjected to ground motion. The EQS dissipates seismic energy through friction of Poly Tetra Fluoro Ethylene (PTFE) disk pad. In general, a force-displacement relationship of EQS has post yield stiffness hardening during large inelastic displacement. In this study, seismic responses of seismically isolated nuclear power plant (NPP) subjected to design basis earthquake (DBE) and beyond design basis earthquakes (150% DBE and 167% DBE) are compared considering the post yield stiffness hardening effect of EQS. From the results, it can be observed that if the post-yield stiffness hardening effect of EQS is increased, the displacement response of EQS is reduced, and the acceleration and shear responses of containment structures of NPP is increased.
In this study, Stockbridge damper was adopted to reduce the reponses of structures under earthquakes. A finite element analysis software, SAP2000, was used to simulate the structural response and the control device under dynamic loads. A 3 story frame model and the proposed control device, Stockbridge damper, were designed under laboratory conditions. In this research, a pendulum type tuned mass damper (PTMD) was also adopted in order to compare with the Stockbridge damper. Harmonic loads were applied to verity the control performance of both control devices in each mode. In results, it has been found that the Stockbirdge damper decreases significantly the responses of the structure more than the PTMD under the harmonic loadings. The El Centro and Northridge earthquakes were also applied in order to investigate the performance by both control devices. The responses of the building demonstrate that the Stockbridge damper reduces the response of the building structure during earthquakes more effectively than the PTMD.
Soil-foundation-structure interaction (SFSI) is one of the important issues in the seismic design for evaluating the exact behavior of the system. A seismic design of a structure can be more precise and economical, provided that the effect of SFSI is properly taken into account. In this study, a series of the dynamic centrifuge tests were performed to compare the seismic response of the single degree of freedom(SDOF) structure on the various types of the foundation. The shallow and pile foundations were made up of diverse mass and different conjunctive condition, respectively. The test specimen consisted of dry sand deposit, foundation, and SDOF structure in a centrifuge box. Several types of earthquake motions were sequentially applied to the test specimen from weak to strong intensity of them, which is known as a stage test. Results from the centrifuge tests showed that the seismic responses of the SDOF structure on the shallow foundation and disconnected pile foundation decreased by the foundation rocking. On the other hand, those on the connected pile foundation gradually increased with intensity of input motion. The allowable displacement of the foundation under the strong earthquake, the shallow and the disconnected pile foundation, have an advantage in dissipating the earthquake energy for the seismic design.
Unreinforced masonry (URM) buildings are known to be highly vulnerable to seismic loadings. Although significant physical variation may exist for URM buildings that fall into a same structural category, a single set of fragility curves is typically used as a representation of the seismic vulnerability of the URM structures. This study investigates the effect of physical variation of URM structures on their seismic performance level. Variables that describe the physical variation of the structure are defined based on the inventory analysis. Seismic behavior of the structures is then monitored by changing the variables to investigate the effect of each variable. The analysis results show that among the variables considered the seismic performance of URM building depends on the variation of the width, the aspect ratio, and the number of story. The need for further research on the modeling of the connections between the walls and diaphragms and the torsional effect is also addressed.