점토지반에 설치된 말뚝의 하중전이 특성

이승현,권오순,Lee,Seung Hyun,Kwon,Oh Soon 한국방재학회 2012 한국방재학회논문집 Vol.12 No.2

점토지반에 설치된 강관말뚝의 축방향 하중전이특성을 파악하기 위해 세 가지 하중전이법을 적용하고 해석을 수행하여 그 결과를 상호 비교하였다. 해석지반은 탄성계수와 비배수강도가 말뚝근입깊이에 대하여 일정한 경우와 비례하는 경우를 고려하였다. 해석을 통해 구한 t-z 곡선을 살펴볼 때 극한단위주면마찰력이 발현되는데 필요한 변위량은 일반적으로 알려진 5~10 mm보다 작은 값을 보였다. 해석을 통해 얻은 하중-침하곡선을 살펴볼 때 말뚝선단에 전이되는 하중은 말뚝머리하중에 비해 상당히 작았으나 말뚝에 있어 뚜렷한 극한지지력 발현과 관련하여 큰 역할을 함을 알 수 있었다. 말뚝의 하중-변위곡선에 있어서의 초기 강성은 말뚝머리 근처 지반의 특성값에 큰 영향을 받음을 알 수 있었다. In order to investigate axial load transfer characteristics of a steel pipe pile installed in clay, three kinds of load transfer curves were used for analysis and results of analysis were compared each other. Two kinds of clay were considered for analysis and one of which has constant distribution of elastic modulus and undrained shear strength with depth and the other has linear distribution of those with depth. t-z curves obtained from the analysis show that pile displacements needed to develop maximum skin load transfer are less than the generally known displacement of 5~10 mm. It can be seen from the results of analysis that the amount of load transferred to pile point was small whereas the load transferred to pile point has major effect on the development of ultimate pile load capacity. Initial stiffness of load carrying capacity of a pile was mainly affected by the soil properties near the upper portion of a pile.

진동 측정에 의한 석조문화재 복원 공사 전·후의 동특성 추정

최재성 ( Jae-sung Choi ),조철희 ( Cheol-hee Cho ) 한국구조물진단유지관리공학회 2021 한국구조물진단유지관리공학회 논문집 Vol.25 No.1

보물 제49호 나주 석당간은 성능 저하로 인해 해체 및 복원 공사가 이루어 졌다. 공사시 균열 부위가 보강되고 기울어짐이 개선되었다. 이러한 문화재들의 복원 공사 전 · 후의 강성 변화를 정량적으로 분석하고 데이터베이스로 구축하여 보강 효과에 대한 예측 또는 평가를 할 수 있는 과학적인 비파괴 검사 방법에 대한 연구가 필요하다. 복원 공사 전·후에 진동실험에 의해 측정된 고유진동수와 탄성계수 정보로부터 구조 시스템의 전체적인 강성을 추정할 수 있는 단순 식을 유도하였고, 활용성을 검토하였다. 제시된 방법으로 중요 문화재의 강성을 정기적으로 조사한다면 구조안전진단 필요 시점 또는 보수, 보강의 필요 시점을 추정하는 자료로 활용될 수 있을 것을 판단된다. Naju Seokdanggan, Treasure No. 49, was dismantled and reconstructed due to poor performance. During construction, the crack area was reinforced and the inclination was improved. It is necessary to analyze the stiffness changes before and after the reconstruction of these cultural properties, and to establish a database of related information. In addition, there is a need for research on a scientific non-destructive testing method capable of predicting or evaluating the reinforcing effect. In this study, a simple equation for estimating the overall stiffness of the structural system was derived from information on the elasticity coefficient and the natural frequency measured by vibration tests before and after reconstruction work, and the applicability of the equation was examined. If the stiffness of important cultural properties is regularly investigated by the suggested method, it is judged that it can be used as data to estimate the time when structural safety diagnosis is necessary or when repair or reinforcement is necessary.

TM 마운트용 고무 부품의 정적 및 동적 특성 연구

허신(Shin Hur),김완두(Wan Doo Kim),우창수(Chang Soo Woo),김완수(Wan Soo Kim),이성범(Seong Beom Lee) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The rubber specimens of transmission mount are tested to obtain the hyperelastic and viscoelastic properties by the static and dynamic test, respectively. The static tests are consisted of uniaxial and biaxial tension and pure shear test. Mooney-Rivlin constants are obtained from these test results. Also, the storage and loss moduli are obtained to know the viscoelastic characteristics by dynamic mechanical analyzer. From the static and dynamic test data, the mechanical performances of rubber mount such as static and dynamic stiffness are predicted with finite element analysis. Also, the dynamic tests of rubber mount subjected to static load are carried out to measure the support load and the dynamic stiffness. Finally, the predictions of FEA and the results of experiments are compared.

타이어 트레드 강성에 따른 충격 하쉬니스에 관한 연구

김병삼,이태근 한국기계기술학회 2014 한국기계기술학회지 Vol.16 No.3

The improvement of car driving comfort is requested according to development of automobile manufacturing technology. Therefore, many experts have been studying automotive vibration of normally driving cars to improve automotive driving comfort. Vibration characteristics of a tire play an important role to judge a ride comfort ability and sound quality for a vehicle. A lots of study on the ride and the noise to reduce the vibration in the 20∼100Hz frequency range was being carried out for years. The tire impact due to the bump is the main factor of the vibration in the 20∼100Hz. This vibration is related to the harshness which perceive the displeasure or noise. In this study, we investigated the characteristics of the impact harshness due to the stiffness of the tire tread part according to change the tread compound.

타이어 트레드 강성에 따른 충격 하쉬니스에 관한 연구

김병삼,이태근 한국기계기술학회 2014 한국기계기술학회지 Vol.16 No.3

짐벌 마운트 플레이트 장착용 진동 감쇠 고무의 동특성 실험에 대한 연구

박헌서(Hunsuh Park),곽동기(Dong-Gi Kwag) 항공우주시스템공학회 2023 항공우주시스템공학회 학술대회 발표집 Vol.2023 No.05

에그-박스 코어 형상 변화에 따른 등가 전단 탄성계수

이상연(SangYoun Lee),윤수진(SuJin Yun),박동창(DongChang Park),황기영(KiYoung Hwang) 한국추진공학회 2012 한국추진공학회 학술대회논문집 Vol.2012 No.11

본 논문은 에그-박스 코어 형상 변화에 따른 등가 전단 탄성계수에 대해 다루고 있다. 코어의 등가 전단 탄성계수를 얻는 방법으로 유한요소해석, 수치 해석, 실험기법이 있다. 본 연구에서는 에그-박스코어의 등가 전단 탄성계수를 예측하기 위하여 유한요소해석을 사용하였다. 에그-박스 코어의 피치 길이와 두께 변화에 따른 등가 전단 탄성계수 변화를 확인할 수 있었다. This paper deals with the equivalent shear modulus according to the shape of Egg-Box core. There are three approaches to obtain the equivalent shear modulus of core: a finite element analysis, an analytical study and an empirical method. In this study, A finite element analysis is used to predict the equivalent shear modulus of the Egg-Box core. As a result of the present work, the equivalent shear modulus of Egg-Box core according to the variation of pitch length and thickness can be obtained.

점탄성 제진 요소의 복소동강성계수 산출을 위한 상용유한요소 코드 이용시 복소탄성계수의 정하중 의존성 반영 방법

김광준(Kim, Kwang-Joon),신윤호(Shin, Yun-Ho) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.4

Little attention has been paid to static-strain-dependence of dynamic complex modulus of viscolelastic materials in computational analysisso far. Current commercial Finite Element Method (FEM) codes do not take such characteristics into consideration in constitutive equations of viscoelastic materials. Recent experimental observations that static-strain-dependence of dynamic complex modulus of viscolelastic materials, especially filled rubbers, are significant, however, require that solutions somehow are necessary. In this study, a simple technique of using a commercial FEM code, ABAQUS, is introduced, which seems to be far more cost/time saving than development of a new software with such capabilities. A static-strain-dependent correction factor is used to reflect the influence of static-strains in Merman model, which is currently the base of the ABAQUS. The proposed technique is applied to viscoelastic components of rather complicated shape to predict the dynamic stiffness under static-strain and the predictions are compared with experimental results.

콘크리트궤도의 하부구조 특성이 궤도강성에 미치는 영향

백인혁,이성혁,신응수,박대욱 한국철도학회 2019 한국철도학회논문집 Vol.22 No.8

The optimum track stiffness required to maintain track performance is known as the most important parameterthat determines properties of roadbed, such as the stiffness of the track substructure. Considering that no criteria exist fortrack stiffness for each type of track, it is very important to study the proper track stiffness of each track structure. In thisstudy, full-scale static and dynamic load tests were carried out to investigate the effect of track substructure characteristicson track stiffness and track modulus in slab track systems under the same upper roadbed condition. The test results indicatethat the track modulus is smaller than the proposed value when the reinforced roadbed thickness is below the designstandard. Therefore, it is necessary to reestablish design standards of track stiffness in terms of track maintenance.

에그-박스 코어의 등가 전단 탄성계수

이상연(SangYoun Lee),윤수진(SuJin Yun),박동창(DongChang Park),윤현걸(HyunGull Yoon) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.11

이 논문은 에그-박스 코어의 등간 전단 탄성계수에 대해 다루고 있다. 코어의 등가 전단 탄성계수를 얻는 방법으로 유한요소해석, 수치 해석, 실험이 있다. 이번 연구에서는 에그-박스 코어의 등가 전단 탄성계수를 평가하기 위하여 3점 굽힘 시험을 수행하였으며, 그 결과로부터 상온에서의 에그-박스코어의 등가 전단 탄성계수를 획득하였다. 이 결과를 유한요소해석으로부터 얻어진 결과와 비교하였다. This paper deals with the equivalent shear modulus of the egg-box core. There are three approaches to obtain the equivalent shear modulus of core: a finite element analysis, an analytical study, and an empirical method. In this study, an 3-point bending test is used to evaluate the equivalent shear modulus of the Egg-Box core. As a result of the present work, the equivalent shear modulus of egg-box core at room temperature can be obtained. And this result is compared with the result of finite element analysis.