The objective of the present investigation is to determine the mode I stress-intensity factors along two symmetric surface cracks emanating from a centrally located hole in a rectangular plate (the so-called Round Robin Problem) using the domain integral method. In order to validate the present three-dimensional domain integral implementation, two comparisons were made with benchmark solutions. We first considered the problem of an elliptical crack embedded ...
Small cracks developing from rivet holes in lap joints of fuselage structure have been an issue of concern over the past decade. Stress-intensity factor solutions required to assess the structural integrity of such configurations are lacking. To address this need, the domain integral method was used in this research to obtain the mode I, normalized stress-intensity factor distributions for cracks emanating from a centrally located countersunk rivet hole in a ...
Since the nature of the fiber-matrix interface significantly affects the overall behavior of fiber composites, especially in planes normal to the fiber direction, characterization of interface properties in composites has received attention in the nondestructive evaluation community. In this paper we will compare finite element and analytical methods of inversion for determination of the interphase stiffnesses from the moduli of the composite. The effect of possible errors in measurement of ...
A nondestructive method to characterize the elastic moduli of fiber- matrix interphase in composites from ultrasonic measurements is described. The elastic moduli of the composite are determined from the measured angular dependence of ultrasonic phase velocities. An averaging method for determination of the composite transverse moduli is proposed to account for the composite orthotropy. The SiC fiber has complex structure with carbon core and SiC shell. The transverse elastic properties ...
In this paper we investigate the effect of an inelastic interface layer on the mechanical behavior of a transversely loaded fiber-reinforced composite. A simple linearly viscoelastic model is used to characterize the stiffness and viscosity of the interface separating the fiber and matrix phases. The mechanical response is obtained using the finite element method and calculations are carried out for a unit cell in a periodic array of hexagonally packed ...
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