서지주요정보
압축 예하중을 받고 있는 점탄성 재료의 복소탄성계수 결정 = Determination of complex modulus of viscoelastic materials subject to compressive pre-loading
서명 / 저자 압축 예하중을 받고 있는 점탄성 재료의 복소탄성계수 결정 = Determination of complex modulus of viscoelastic materials subject to compressive pre-loading / 이정학.
저자명 이정학 ; Lee, Jeong-Hak
발행사항 [대전 : 한국과학기술원, 2001].
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8012503

소장위치/청구기호

학술문화관(문화관) 보존서고

DME 01041

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초록정보

Viscoelastic components employed for vibration isolation or shock absorption in automobiles, machines and buildings are often subject to a high level of static compression. From the dynamic design point of view, it is essential to predict complex stiffness of the viscoelastic components accurately and efficiently, which requires first of all information about the complex modulus of the viscoelastic materials under operational environmental conditions, especially under the static compression. Although several approximate formulas were developed to predict the dynamic properties of viscoelastic materials subject to heavy static deformation, most of the studies were concerned with static extension rather than compression under which most vibration or shock isolators actually operate. In this study, a procedure to estimate complex modulus of incompressible viscoelastic materials from stiffness measurements as functions of frequency under heavy compressive pre-strain is presented. Measurements of the complex modulus from two kinds of circular cylindrical specimens subject to static compression are conducted. As bonding of the specimen at its both ends is inevitable in compression test, it is necessary to compensate for the bonding effects in treating the experimental data. The bonging effect is computed in this study that concerns heavy static compression by applying a finite element code to the specimen. In order to represent the modulus as functions of pre-strain and frequency, two existing method are introduced and then, two new methods are investigated. Lianis proposes a formula that takes into account the coupling between the frequency and the static pre-strain effects is presented. This formula can predict the complex modulus successfully in the uni-axial deformation, but it is still a little complicated equation and has to be modified to be able to predict other deformational conditions. Morman proposes a formula that assumes that the complex modulus can be obtained by multiplication of the frequency effects at a reference pre-strain and the static modulus, but the formula is shown not so successful. The new procedure presented in this study is obtained by modification of the Morman’s formula. The Morman’s formula assumes that the trend of the dynamic modulus at a frequency versus static compression is same that of the static modulus. In reality, trend of the static modulus is different from that of the dynamic modulus. So, it is necessary to exploit the trend of dynamic modulus rather than the static modulus. In order to consider the trend of dynamic modulus, the relaxation modulus, which is a function of frequency, in the Morman’s equation is substituted by a function of frequency and pre-strain. After that, two methods are proposed in this study. One combines the frequency effects at a static compression and the static compression effects at a chosen frequency. Another takes into account the gradient of storage and loss modulus. Finally, experimental results were treated by these new methods and performance and practical limitation of the methods are comparatively discussed.

서지기타정보

서지기타정보
청구기호 {DME 01041
형태사항 xiii, 119 p. : 삽도 ; 26 cm
언어 한국어
일반주기 부록 : 1, Green-rivlin theory. - 2, 형상계수를 이용하여 양 끝단이 고정된 원통형 시편의 압축력 보정. - 3, 제한적인 주파수 및 시간 영역에서의 실험데이터를 이용한 상관관계 규명의 한계
저자명의 영문표기 : Jeong-Hak Lee
지도교수의 한글표기 : 김광준
지도교수의 영문표기 : Kwang-Joon Kim
수록잡지명 : "Characterization of complex modulus of viscoelastic materials subject to static compression". Mechanics of time dependent materials
학위논문 학위논문(박사) - 한국과학기술원 : 기계공학전공,
서지주기 참고문헌 : p. 116-119
주제 점탄성 재료의 복소탄성계수
압축 예하중
동강성계수
Complex Modulus of Viscoelastic Materials
Compressive Pre-Loading
Dynamic Stiffness
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