ELASTIC FEM ANALYSIS OF FIBER PUSH-OUT TEST FOR C C COMPOSITES/

To study mechanical properties of fiber, matrix and their interface in C/C composites, fiber push-out test has been carried out. Where, to d ecompose the deformation, measured from indenter displacement, into lo cal deformation is essential for mechanistic understandings. But up to now. there has been no systematic study on this effect. In this study , as the preliminary analysis of the push-out tests, those with a vari ety of groove width on specimen holder were performed and the elastic deformations of specimen were analyzed by a finite-element method (FEM ). Materials used were unidirectionally reinforced C/C composites. Fib er push-out tests were carried out by utilizing dynamic ultra micro in dentation test machine. For the cases of 20 and 100 mu m groove, plate aus which indicate the occurrence of fiber push-out could be seen in L oad-displacement curves (indentation curves) and there was a differenc e in the duration of plateau. On the other hand, for all the cases, an y difference could not be seen before plateaus. Now by using axis symm etrical FEM model, elastic deformation of CIC composites before push-o ut was calculated. From the results of calculation, the effect of groo ve width on indentation curves within elastic regime was considered to be little. But there was a large difference in the distribution of th e stress transverse to carbon fiber direction on fiber-matrix interfac e between 20 and 100 mu m, and this was considered to be the origin of the difference of the duration of plateau.