• 한국안전학회지
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• 제24권4호
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• pp.53-58
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• 2009

The importance of process for repair and reinforcement of the bridge is increasing because of the lack of the fatigue load and stress, a lowering of the bridge load carrying capacity owing to impact and oscillation, deterioration on cultivation periods of the bridge, etc. Typically the experimenter values the bridge load carrying capacity by the real rating factor and response modification factor in bridge load rating through static load test and dynamic load test. But the error occurred in reliability of response modification factor in bridge load rating according to experience of experimenter. so tests of connecting probability theory and valuation of the bridge recently. The study is to compute the real load carrying capacity of the bridge and the rating factor and response modification factor on grade of the bridge, and calculate the probability of over-loaded truck load from Weigh In Motion(WIM) Data in FORTRAN programming applying to Monte-Carlo Simulation. At the result of this study, it is acquired that the new grade is computed for the probability of over-loaded truck load and surface inspection. The A grade is over 1.95, B grade is $1.55{\sim}1.94$, C grade is $1.26{\sim}1.54$, D grade is $1.14{\sim}1.25$, E grade is under 1.13 of rating factor, respectively.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.749-756
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• 2006

Because of the orthotropic elastic properties and significant two-way bending action, orthotropic plate theory may be suitable for describing the behavior of concrete filled grid bridge decks. Current AASHTO LRFD Bridge Design Specification(2004) has live load moment equations considering flexural rigidity ratio between longitudinal and transverse direction, but the Korea highway bridge design specification(2005) doesn't. The Korea highway bridge standard specification LRFD(1996) considers an orthotropic plate model with a single load to estimate live load moments in concrete filled grid bridge decks, which may not be conservative. This paper presents live load moment equations for truck and passenger car, based on orthotropic plate theory. The equations of truck model use multiple presence factor, impact factor, design truck and design tandem of the Korea highway bridge standard specification LRFD(1996). The estimated moments are verified through finite-element analyses.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 봄 학술발표회 논문집
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• pp.111-118
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• 1996

Dynamic load models which show the practical behavior of truss bridge subjected to moving train load are presented. Three basically approaches are available for evaluating structural response to dynamic effects : moving force, moving mass, and influence moving force and mass. Simple warren truss bridge model is selected in this research, and idealized lumped mass system, modelled as a planar structure. In the process of dynamic analysis, the uncoupled equation of motion is derived from simultaneous equation of the motion of truss bridge and moving train load. The solution of the uncoupled equations of motion is solved by Newmark-$\beta$ method. The results show that dynamic response of moving mass and static analysis considering the impact factor specified in the present railway bridge code was nearly the same. Generally, the dynamic response of moving force is somewhat greater than that of moving mass. The dynamic load models which are presented by this study are obtained relatively adequate load model when apply to a truss bridge.

• Structural Engineering and Mechanics
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• 제71권3호
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• pp.245-255
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• 2019

In this paper, an inverted-pendulum model consisting of a point supported by spring limbs with roller feet is adopted to simulate human walking load. To establish the kinematic motion of first and second single and double support phases, the Lagrangian variation method was used. Given a set of model parameters, desired walking speed and initial states, the Newmark-${\beta}$ method was used to solve the above kinematic motion for studying the effects of roller radius, stiffness, impact angle, walking speed, and step length on the ground reaction force, energy transfer, and height of center of mass transfer. The numerical simulation results show that the inverted-pendulum model for walking is conservative as there is no change in total energy and the duration time of double support phase is 50-70% of total time. Based on the numerical analysis, a dynamic load factor ${\alpha}_{wi}$ is proposed for the traditional walking load model.

• Computers and Concrete
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• 제18권3호
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• pp.389-404
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• 2016

In this study, effects of impact loads on reinforced concrete (RC) plates are examined analytically. During examination of RC plates, they were exposed to impact loading with two different support conditions in three different sizes. RC plates in different support conditions were analyzed with Concrete Damage Plasticity Model (CDP) and reinforcing steel was modeled with Classical Metal Plasticity Model (CMP) by ABAQUS finite element software. After the analysis it is found that impact loads, displacements, energy absorption capacities and damage patterns are changed due to support conditions and plate sizes. Results that are obtained from RC plate experiments in literature under impact loads are found to be similar with the results of numerical analysis with CDP material models.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.394-402
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• 2009

To investigate the heavy-weight impact noise of apartment houses, numerical analysis was performed. The analysis acoustic pressure consider acoustic mode by finite element method. The variables considered effecting on the acoustic pressure are the Acoustic mode, acoustic damping, and the impulse load. The heavy-weight impact noise is a changeable value in the room. Since the most part of the frequency component of heavy-weight impact noise has low frequency. The noise in low frequency is related to the vibration of structure, the reflection of acoustic wave caused by wall and the standing wave called by acoustic mode. The prediction by the numerical analysis was verified with test result of the heavy weight-impact noise at apartment houses.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.403-404
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• 2010

본 논문에서는 큰 시험체 크기와 많은 충격에너지를 필요로 하는 섬유보강 시멘트 복합재료의 충격 실험을 수행하기 위한 새로운 종류의 충격시험 장비를 제안하였다. 제안한 충격시험장치는 위치에너지나 운동에너지를 사용하는 기존 충격시험와 달리 선형변형에너지를 사용하고, 기존의 다른 충격시험장비와 비교하여 크기가 훨씬 작고 경제적이며 안전하다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.111-114
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• 2003

Thermosets are highly cross-linked polymers with a three-dimensional molecular structure. The network structure gives rise to mechanical properties, however, one major drawback of thermosets, which also results from their network structure, is their poor resistance to impact and to crack initiation. In this study, to solve this problem, the reactive thermoplastics such as amine terminated polyetherimide (ATPEI), ATPEI-CTBN-ATPEI(ABA) triblock copolymer, CTBN-ATPEI(AB) diblock copolymer, and carboxyl group modified ATPEI was synthesized, after that blended with epoxy resin, and the carbon fiber reinforced composites were fabricated. The impact load, energy, and delamination were investigated by using drop weight impact test and C-scan test. As a results, the ABA/epoxy blend system showed good impact properties.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.91-94
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• 2003

Laminated composites are liable to fatal damage under impact load due to the fact that they have no reinforcement in the thickness direction. To overcome the inherent weakness, three dimensional (3D) textile reinforcements have drawn much interests. In this paper, impact performance of 2D and 3D textile composites has been characterized. For 2D composites, fiber bundle size and fiber pattern have been varied. For 3D composites, orthogonal woven preforms of different density and type of through-thickness fibers have been studied. To assess the damage after the impact loading, specimens were subjected to C-scan nondestuctive inspection. Compression after impact (CAI) were also conducted in order to evaluate residual compressive strength.

• International Journal of Safety
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• 제4권1호
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• pp.1-7
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• 2005

The direction of the applied load and displacement rate on the femur during falls may be an important factors in the etiology of hip fractures. Nonetheless, previous studies did not consider these two factors simultaneously for falling condition. Therefore, in the present study, an impact test system is developed to simulate the falling condition and the influence of impact angle on the deformation pattern changes of proximal femur is investigated. The results showed that a slight variation in impact angle quite affects deformation pattern of the proximal femur. Along with bone mineral density and trabaecular morphology, the impact angle can be another important factor affecting the structural capacity of the proximal femur.