Polycarbonate와 Polyester Resin의 동적 균열전파속도와 동적 응력확대계수

이억섭; 한민구

Polymer(Korea), Vol.16, No.4, 389-398, July, 1992

Export Citation

Polycarbonate와 Polyester Resin의 동적 균열전파속도와 동적 응력확대계수

Dynamic Stress Intensity Factors and Dynamic Crack Propagation Velocities in Polycarbonate and Polyester Resin

이억섭, 한민구

초록

신소재로 알려져 있는 재료들 중 두가지 고분자재료들에 대한 동적 파괴특성을 동적 광탄성실험법과 동적 유한요소법을 이용하여 규명하였다. Thermoplastic재료인 Polycarbonate와 Thermoset재료인 Polyester Resin을 시편으로 사용하여 이들의 기계적인 성질, 시편의 기하학적인 형상이 이들 재료내에서 빠르게 전파하는 동적 균열의 전파속도와 동적 균열선단의 동적 응력확대계수와의 상호관계에 미치는 영향을 체계적으로 연구하였다. 이들 고분자재료의 동적 균열정지인성치는 시편의 기하학적인 형상이나 동적 균열전파개시에 의존함을 밝히고 이들 재료내에서의 동적균열전파속도의 최대값은 재료의 종류, 시편의 기하학적인 형상, 하중방법 등에 크게 의존됨을 확인하였다. 이들 고분자재료내에서의 동적 균열전파거동은 미소한 시간간격으로 보면 "전파-정지-전파-정지"의 과정이 계속적으로 진행되어 일어난다는 사실을 알 수 있었다. 또한 동적 응력확대 계수와 동적 균열전파속도의 관계는 전형적인 "Γ"형으로 나타남을 확인하였다.

Dynamic fracture characteristics of polycarbonate and polyester were investigated. The dynamic crack propagation velocities in these polymeric materials were measured by using both high speed camera system and silver paint grid method developed and justified in the INHA Fracture Mechanics Laboratory. The measured crack propagation velocities were fed into the INSAMCR code(a dynamic finite element code which has been developed in the INHA Fracture Mechanics Laboratory) to extract the dynamic stress intensity factors. It has been confirmed that both dynamic crack arrest toughness and the static crack arrest toughness depend on both the geometry and the dynamic crack propagation velocity of specimens. The maximum dynamic crack propagation velocity of polymeric materials was found to be dependent on the material property, geometry and the type of loading. The dynamic cracks in these polymers seemed to propagate in a successive manner, involving distinguished 'propagation-arrest-propagation-arrest' steps on the microsecond time scale. It was also found that the relationship between dynamic stress intensity factor and dynamic crack propagation velocites might be represented by the typical 'Γ' shape.

[References]

Andrews EH, "Fracture in Polymers," American Elsevier (1968)
Williams JG, "Stress Analysis of Polymers," Ellis Horwood Limited (1980)
이억섭, 한국정밀공학회지, 3, 40 (1986)
Lee OS, KSME J., 1(1), 65 (1987)
Lee OS, Williams JH, Mater. Evaluation, 49(3), 351 (1991)
Ramulu M, Experimental Mechanics, 4, 344 (1985)
Kobayashi AS, "Experimental Techniques in Fracture Mechanics," pp. 126~145, Society for Experimental Stress Analysis, Westport, Connecticut (1973)
Dally JW, Experimental Mechanics, 12, 441 (1978)
Kobayashi T, Dally JW, "Fast Fracture and Crack Arrest," ASTM STP 627, pp. 257~273, American society for Testing and Materials, Philadelphia (1977)
Shukla A, Nigam H, Eng. Fracture Mech., 25(1), 91 (1986)
Rosakis AJ, Eng. Fracture Mech., 13, 331 (1980)
Dally JW, Fourney WL, Irwin GR, Int. J. Fracture, 27, 159 (1985)
Atluri SN, Nishioka T, Int. J. Fracture, 27, 245 (1985)
Riley WF, Dally JW, Experimental Mech., 9, 27N (1969)
이억섭, 한민구, 대한기계학회논문집, 13(5), 947 (1989)

[1] Andrews EH, "Fracture in Polymers," American Elsevier (1968)

[2] Williams JG, "Stress Analysis of Polymers," Ellis Horwood Limited (1980)

[3] 이억섭, 한국정밀공학회지, 3, 40 (1986)

[4] Lee OS, KSME J., 1(1), 65 (1987)

[5] Lee OS, Williams JH, Mater. Evaluation, 49(3), 351 (1991)

[6] Ramulu M, Experimental Mechanics, 4, 344 (1985)

[7] Kobayashi AS, "Experimental Techniques in Fracture Mechanics," pp. 126~145, Society for Experimental Stress Analysis, Westport, Connecticut (1973)

[8] Dally JW, Experimental Mechanics, 12, 441 (1978)

[9] Kobayashi T, Dally JW, "Fast Fracture and Crack Arrest," ASTM STP 627, pp. 257~273, American society for Testing and Materials, Philadelphia (1977)

[10] Shukla A, Nigam H, Eng. Fracture Mech., 25(1), 91 (1986)

[11] Rosakis AJ, Eng. Fracture Mech., 13, 331 (1980)

[12] Dally JW, Fourney WL, Irwin GR, Int. J. Fracture, 27, 159 (1985)

[13] Atluri SN, Nishioka T, Int. J. Fracture, 27, 245 (1985)

[14] Riley WF, Dally JW, Experimental Mech., 9, 27N (1969)

[15] 이억섭, 한민구, 대한기계학회논문집, 13(5), 947 (1989)