Biaxial fatigue properties of thin-walled composite tubesA testing method for obtaining fatigue and fracture data under biaxial loading and for negative R-ratios is described. Thin-walled tubes of 1-in. outer nominal diameter with a tapered grip section were tested in an Axial-Torsion Servohydraulic Testing Machine with a 463 Data Control Processor at frequencies below 10 Hz up to the 1-million cycle range. Room temperature, uniaxial constant amplitude fatigue data for high temperature cure graphite-epoxy material are presented at R = -0.4 for a (+, - 5 deg) fiber orientation. The fatigue curve is almost horizontal. Tests on (+, - 5 deg) 'SP-328' resulted in failures which predominantly originated in the grip section. Presently, a new specimen design is being tested intended to eliminate cracking in the grip section. Biaxial in-phase loading of (0/+, - 45) tubes of Fiberite graphite-epoxy resulted in much steeper fatigue curves than observed under uniaxial loading.
Document ID
19860033695
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Krempl, E. (Rensselaer Polytechnic Inst. Troy, NY, United States)
Elzey, D. M. (Rensselaer Polytechnic Inst. Troy, NY, United States)
Ayar, T. (Rensselaer Polytechnic Inst. Troy, NY, United States)
Loewy, R. G. (Rensselaer Polytechnic Institute, Troy, NY, United States)