Bridging fiber stress distributions during fatigue crack growth in SCS-6/Timetal{reg_sign}21S
- Univ. of Dayton Research Institute, Dayton, OH (United States)
- NM/MLLN, Wright Lab. Materials Directorate, Wright-Patterson Air Force Base, OH (United States)
This presentation discusses the results of an experimental and analytical investigation of bridging fiber stress distributions for cracks growing in a Timetal{reg_sign}21S metal matrix composite reinforced with silicon-carbide (SCS-6) fibers. The fatigue crack growth tests were conducted at room temperature using center-hole and center-cracked geometries. [0]{sub 4} and [0/90]{sub s} layups were tested at a frequency of 1.0 Hz. During the crack growth tests, crack opening displacement ranges were measured at different locations along the crack using a laser interferometric displacement gage (IDG) system. In addition, residual crack opening displacements (at zero applied load) were measured using a scanning electron microscope. A procedure was developed to generate the absolute crack opening displacement profiles at different crack lengths and stress levels using the measured residual and laser IDG displacement measurements. Using the weight function method, the bridging fiber stress distributions were determined by correlating the predicted and measured crack opening displacements. The results show that the shape of the absolute bridging stress distribution could be different from that of the bridging stress range distribution. The bridging fiber stress range is near-linear with non-zero stresses at the crack tip. The effect of crack length, applied stress level, geometry and layup on the magnitude and shape of the bridging stress distribution will be discussed. The deduced bridging stress distributions will also be compared with those predicted using available crack bridging models such as the fiber pressure and shear lag models.
- OSTI ID:
- 175286
- Report Number(s):
- CONF-950686-; TRN: 95:006111-0243
- Resource Relation:
- Conference: Joint applied mechanics and materials summer meeting, Los Angeles, CA (United States), 28-30 Jun 1995; Other Information: PBD: 1995; Related Information: Is Part Of AMD - MD `95: Summer conference; PB: 520 p.
- Country of Publication:
- United States
- Language:
- English
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