Full-field analysis of notch effects of 3D carbon/carbon composites

Abstract

Carbon fiber reinforced carbon matrix composites (C/Cs), as important candidate aviation and aerospace materials , have good prospects for application in extreme environments. However, notch effects of C/Cs have not been studied adequately. In this work, the notch effects of 3D-C/C composites were investigated by the full-field measurement digital image correlation method. Six kinds of specimens with different notch patterns including one central hole, multi-holes, and double edge notches, were examined to analyze their mechanical properties. The tests were carried out on MTS 809 testing machine and the deformations of specimens were monitored by a CCD camera. Using the full-field measurement , both the local mechanical properties (stress concentration , shear damage, and fracture behavior) and the globe properties (notch sensitivity and tensile behavior) were studied. The results indicated that the fracture stress on the net cross section was constant and it was independent on the material heterogeneity, notch patterns, and notch depth.

A Statistical Mesoscale Approach to Model the Size Effect on the Tensile Strength of Notched Woven Composites

“…Experimental models [6][7][8][9] that model the tensile strength of open-hole specimens with empirical formulations based on the observed failures. Full-field strain analysis was employed in [10,11]; • Numerical models that describe the complexity of the problem, accounting for different damage models describing the interaction of failure modes (e.g., delamination, inplane cracking) [12][13][14][15][16][17][18][19][20] or advanced finite element methods [21,22];…”

Experimental and Numerical Analysis of Notched Composites Under Tension Loading

“…This effect is because of the crucial role delamination may play in the strength and failure mechanisms in open hole samples tested in tension. Qin et al [6] used Digital Image Correlation (DIC) method to study the notch effect with different patterns and localizations of carbon fiber reinforced carbon matrix composites. Using the full-field measurement, both the local mechanical properties (stress concentration, shear damage, and fracture behavior) and the globe properties (notch sensitivity and tensile behavior) were studied.…”