A PARAMETRIC STUDY OF VARIABLES THAT AFFECT FIBER MICROBUCKLING INITIATION IN COMPOSITE LAMINATES - EXPERIMENTS Academic Article uri icon

abstract

  • The objectives of this research are to investigate the effects of stacking se quence (orientation of plies adjacent to the 0 plies), free surfaces, fiber/matrix interfacial bond strength, initial fiber waviness, resin-rich regions, and nonlinear resin shear consti tutive behavior on fiber microbuckling initiation. Three thermoplastic composite material systems are used in this investigation. The materials are the commercial APC-2 (AS4/ PEEK), QUADRAX Interlaced Tape, and a poor interface experimental material, AU4U/ PEEK. Notched compression specimens are studied at 21C, 77 C, and 132C. Observa tions indicate that the notch radius controlled fiber microbuckling initiation, and thus compression strength, by dictating the unsupported fiber length at the notch. The numeri cal results from a companion paper [1] are compared qualitatively with these experimental results. The results show that increasing the test temperature, locating 0 plies at the free surface of the laminate, and degrading the fiber/matrix interfacial bond strength reduce the resistance to fiber microbuckling initiation in these notched laminates. The fiber micro buckling initiation strain is shown to be a constant, regardless of stacking sequence, for these notched laminates. Experimental results show that resin-rich regions also reduced the resistance to fiber microbuckling initiation.

published proceedings

  • JOURNAL OF COMPOSITE MATERIALS

author list (cited authors)

  • GUYNN, E. G., BRADLEY, W. L., & OCHOA, O. O.

citation count

  • 22

complete list of authors

  • GUYNN, EG||BRADLEY, WL||OCHOA, OO

publication date

  • November 1992