A Study of Stress Intensity Factors using Micro Fiber Composite Sensors

Oh, Dong-Jin; Kim, Myung-Hyun

Journal of KWJS 2011;29(3):76-81.
Published online July 7, 2011.

MFC 센서를 이용한 응력 확대 계수 측정에 관한 연구

A Study of Stress Intensity Factors using Micro Fiber Composite Sensors

Abstract

Recently, the structural failures due to fatigue occur frequently with the increase of size of ships and offshore structures. In this respect, the assessment of fatigue life and the residual strength are very important. Currently, the smart materials technology has demonstrated a variety of possibilities for a diagnosis of structural strength and structural health condition for large structures. The benefits and feature of the MFC sensor are more flexible, durable and reliable than conventional smart material. In this study, Micro Fiber Composite (MFC) sensor for the measurement of stress intensity factor (SIF) of two dimensional cracks induced in a structure is developed. Two MFC sensors are placed in the vicinity of the crack tip close to each other with the crack tip in between them. The SIFs of Mode Ⅰ(K_Ⅰ) as well as of Mode Ⅱ(K_Ⅱ) based on the piezoelectric constitutive law and fracture mechanics are calculated. In this study, the SIF values measured by MFC sensors are compared with the theoretical results and measured value.

Key Words: MFC sensor, Stress intensity factor(SIF), Fatigue crack growth, Piezoelectric