• Geomechanics and Engineering
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• 제31권3호
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• pp.319-328
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• 2022

Ensuring the integrity of a country's infrastructure is necessary to protect surrounding communities in case of disaster. Embankment dam systems across the US are an essential component of infrastructure, referred to as lifeline structures. Embankment dams are crucial to the survival of life and if these structures were to fail, it is imperative that states be prepared. Southern California is particularly concerned with the stability of embankment dams due to the frequent seismic activity that occurs in the state. The purpose of this study was to create a numerical model of an existing embankment dam simulated under seismic loads using previously recorded data. The embankment dam that was studied in Los Angeles, California was outfitted with accelerometers provided by the California Strong Motion Instrumentation Program that have recorded strong motion data for decades and was processed by the Center for Engineering Strong Motion Data to be used in future engineering applications. The accelerometer data was then used to verify the numerical model that was created using finite element modeling software RS2. The results from this study showed Puddingstone Dam's simulated response was consistent with that experienced during previous earthquakes and therefore validated the predicted behavior from the numerical model. The study also identified areas of weakness and instability on the dam that posed the greatest risk for its failure. Following this study, the numerical model can now be used to predict the dam's response to future earthquakes, develop plans for its remediation, and for emergency response in case of disaster.

• 대한기계학회논문집A
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• 제25권3호
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• pp.353-361
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• 2001

Recently the boundary element method has been developed swiftly. The boundary element method is an efficient and accurate means for analysis of two dimensional elastic crack problems. This paper is concerned with the evaluation and the prediction of the stress intensity factor(SIF) for the crack emanating from the circular hole using boundary element method-neural network. The SIF of the crack emanating from the hole was calculated by using boundary element method. Neural network is used to evaluate and to predict SIF from the results of boundary element method. The organized neural network system (structure of four processing element) was learned with the accuracy 99%. The learned neural network system could be evaluated and predicted with the accuracy of 83.3% and 71.4% (in cases of SIF and virtual SIF). Thus the proposed boundary element method-neural network is very useful to estimate the SIF.

• 한국농공학회지
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• 제24권3호
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• pp.73-83
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• 1982

study aims to derive a rational method for the analysis of the farm silo supported on an elastic foundation in which it is assumed that the reaction pressure of the soil at a point is proportional to the deflection at that point. In order to investigate the effects of an elastic foundation on the behaviour of the structures on it, the analysis of the farm silo resting on an elastic foundation was compared with the solution that the ground support may be assumed uniform (which was obtained from part I of this paper). To calculate the deformation of an elastic foundation, Boussinesq's solution which allows an interaction of the various parts of ground was adopted. In this case, the foundation was treated as a superparametric element additionally. In the evaluation of an element stiffness matrix, Gauss quadrature' was used. In above numerical integration, 3-point rule for the farm silo wall and the footing was introduced and 2-point rule for the evaluation of a reaction between the footing and the elastic foundation was adopted. The stresses of a farm silo on an elastic foundation were smaller than those which the distribution of contact pressure between the footing and the soil is assumed uniformly. Since the differences of stresses were remarkable in PS structures than RC structures, it is desirable that designers take into account the effect of an elastic foundation for the case of PS structures. It can be noted that while the effect of an elastic foundation was more conspicuously observed in near of the ground, the value of stresses at far from the soil was little affected by an supported soil.

• 한국생산제조학회지
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• 제22권5호
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• pp.782-788
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• 2013

This study addresses the issue of safety of the splash guard of a computer numerical control (CNC) machine tool at the design stage. As an impact test for evaluating safety requirements such as strength under the safety regulation is an expensive and iterative task, it is necessary to develop a new method to minimize the task of the impact test for development of the machine tool. In this study, explicit finite element method was adopted for replacement of the impact test of the splash guard of a machine tool at the design stage. A finite element model was developed for implementing the impact test on an actual vertical CNC lathe and then produced the analysis including plastic strain and deformation to enable the safety of its splash guard to be determined. The analysis results demonstrated that the finite element method can be applied to safety evaluation for design of the splash guard of a CNC machine tool.

• 대한약침학회지
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• 제16권4호
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• pp.49-53
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• 2013

The purpose of this study was to report the effect of a combination of Sa-am five-element acupuncture and eight-principle pharmacopuncture (EPP) for the treatment of an essential tremor (ET). This study reviewed the medical records treated at OO Korean medical hospital for ET by using diverse types of acupuncture without herbal medicine, other types of physical therapy, and western medication related ET or Parkinson's disease and was performed after the approval of the institutional review board (IRB). The three cases that were finally selected were then extracted and reviewed. The three cases that were finally selected involved three women in their 70s to 80s. The evaluation of the progress was made by using the numeric rating scale. A combined treatment, the method of liver excess (肝乘格), from among Sa-am five-element acupuncture, and Hwangyeonhaedoktang EPP at CV23 and CV17, was applied to all cases. In all three cases, the ET was improved, and recurred ETs improved with the same treatment. The results suggest that the combined treatment of Sa-am five-element acupuncture and Hwangyeon-haedoktang EPP may be effective for treating an ET, even though this conclusion is based on only three cases.

• 공학교육연구
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• 제18권3호
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• pp.24-32
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• 2015

The purpose of this research is to consider theoretical points of view on a preceding research related to an engineering design and abstract the definition of engineering design ability, its subdivision and element on the basis of experts' recognition. To achieve this goal, various literature researches were carried out by examining domestic and foreign articles in journals, lots of dissertations, and books related to engineering design through theoretical consideration. And to secure the validity on the definition of engineering design ability, its subdivision and element through the theoretical study, a feasibility evaluation method by the experts was applied. And the feasibility evaluation of the experts was conducted through 2 stages. The major conclusions of this study are as follows. Firstly, based on the experts' recognition on the definition of engineering design ability, its subdivision and element, which were revised through the 1st feasibility evaluation and then utilized in the 2st one, the validity was confirmed, and the subdivisions of the engineering design ability were divided into 5 and the elements of the subdivision ability were 33. Secondly, the engineering design ability was defined as "the one to design a realizable product with consumers' demand fully satisfying, based on a knowledge application ability, thinking ability, communication ability, problem-solving ability, and teamwork ability to solve engineering problems." Thirdly, the subdivisions of the engineering design ability were divided as a knowledge application ability, thinking ability, communication ability, problem-solving ability, and teamwork ability.

• 비파괴검사학회지
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• 제20권2호
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• pp.130-137
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• 2000

대표적인 비파괴 평가 기술들 중의 하나인 초음파응용 기술은 각종 구조물에 존재하는 내부결함에 의한 산란신호를 통해 건전성을 평가하는 기법이므로 결함의 신뢰성 높은 정량적 평가를 위해서는 결함으로부터의 초음파 산란신호특성에 대한 기본적 이해가 필수적이며 따라서 이를 위한 모델링 수치해석 연구가 요구된다. 모델링 기법들은 비파괴 평가기술에 있어서 중요한 역할을 하고 있고 많은 모델링 기법들이 결함의 탄성파 산란문제를 해석하기 위하여 사용되어 오고 있다. 본 연구에서는 다양한 수치기법들 중 탄성파 산란문제 해석에 있어 많은 장점을 가지고 있는 동탄성 경계요소법에 대하여 자세히 소개하고, 응용 예로서 경계요소법을 이용한 기공결함의 수평횡파 산란장 해석과 표면균열의 표면파 산란장 해석을 소개한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.61-64
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• 2006

A common form of construction for apartment buildings consists of walls and coupling element. But, the structural behavior of coupling element are very complex and affected by the properties of coupling element. The propose of this paper is to evaluation the behavior of coupling element in wall-dominant system. An 1/2 scale three specimens was constructed and under cyclic loads. The specimen was consisted of opening walls and coupling element as well as floor slabs. From the result of this study, in coupling slabs, the stresses were not uniform across the width. And the effective width of coupling slabs was found smaller than the that of predicted from previous studies.

• 대한기계학회논문집A
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• 제24권6호
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• pp.1547-1556
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• 2000

In this paper, an evaluation method of fracture toughness to apply interfacial fracture mechanics was investigated in adhesively bonded double-cantilever beam (DCB) joints. Four types of adhesively bonded DCB joints with an interface crack were prepared for analyses of the stress intensity factors using boundary element method(BEM) and the fracture toughness test. From the results of BEM analysis and fracture toughness experiments, it is found that the stress intensity factor, K1 is a parameter driving the fracture of adhesively bonded joints. Also, the evaluation method of fracture toughness by separated stress intensity factors of mixed mode cracks was proposed and the influences of mode components for its fracture toughness are investigated in adhesively bonded DCB joints.

• Architectural research
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• 제10권2호
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• pp.37-42
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• 2008

This study is to get the proper evaluation of the residual property of reinforced concrete beam exposed to fire. This study focused on the strength resistance and analytical evaluation of RC members exposed high temperature. And this study is the basis analytical research to conduct the other studies. To analysis by the finite element method, the Total-RC program was used to analysis it and the Total-Temp program was also used to analysis the temperature distributions at the section. All of results were compared with the pre-existing experimental data of simple supported beam. Using it, the parameters influencing the structural capacity of the high temperature-damaged RC members and residual strength estimation are investigated. The temperature distribution and the structural capacity at the section are calculated in this step. An application of this method is compared with the heating test result and residual property test for simple supported beam which is subjected to ISO 834 test fire. The results of this study are as follows; 1) The loads-displacement relationship of RC beam, considering initial thermal stress of cross section and heat transfer analysis are estimated comparing analytical value with pre-existing experimental results. 2) by the heating time (0, 1, 2 hours), the results of analysis with parameters show that the load capacity exposing at fire is affected.