| Summary: | 碩士 === 國立清華大學 === 動力機械工程學系 === 93 === Stress Intensity Factor (SIF) is a vital target of material intensity in evaluating. This work is in terms of the principle of composite material mechanics and linear fracture mechanics, writing the program to calculate the boundary conditions of the model and simulating there is a Mode-I crack in vertical fiber direction of the orthotropic composite material, which is utilizing ANSYS engineering analysis software to build the model. We suppose the stress intensity factor is 1 under macroscopic scale, and get dimensionless stress intensity factor in the crack tip in two different positions of two materials under relative microscopic scale. We discuss how the stress intensity factor is affected by Nonhomogeneous material under the diverse matrixes and fiber materials, such as elastic modulus ration、volume fraction ratio and Poisson’s ratio.
From the result of this work, we will know no matter the volume fraction, SIFs is smaller than one in fiber when crack tip is in the matrix. When elastic modulus ration raises, the difference increases, too. We observe clearly the change of elastic modulus ration affects slightly SIFs of crack tip in different analytic point of matrix, and concerns strongly in the fiber which is under major external force.
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