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Implementation of thermal residual stresses in the analysis of fiber bridged matrix crack growth in titanium matrix composites
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Johnson, W. Steven Bakuckas Jr., John G. |
| Copyright Year | 1994 |
| Description | In this research, thermal residual stresses were incorporated in an analysis of fiber-bridged matrix cracks in unidirectional and cross-ply titanium matrix composites (TMC) containing center holes or center notches. Two TMC were investigated, namely, SCS-6/Timelal-21S laminates. Experimentally, matrix crack initiation and growth were monitored during tension-tension fatigue tests conducted at room temperature and at an elevated temperature of 200 C. Analytically, thermal residual stresses were included in a fiber bridging (FB) model. The local R-ratio and stress-intensity factor in the matrix due to thermal and mechanical loadings were calculated and used to evaluate the matrix crack growth behavior in the two materials studied. The frictional shear stress term, tau, assumed in this model was used as a curve-fitting parameter to matrix crack growth data. The scatter band in the values of tau used to fit the matrix crack growth data was significantly reduced when thermal residual stresses were included in the fiber bridging analysis. For a given material system, lay-up and temperature, a single value of tau was sufficient to analyze the crack growth data. It was revealed in this study that thermal residual stresses are an important factor overlooked in the original FB models. |
| File Size | 1567578 |
| Page Count | 46 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19940023155 |
| Archival Resource Key | ark:/13960/t3033s25m |
| Language | English |
| Publisher Date | 1994-02-01 |
| Access Restriction | Open |
| Subject Keyword | Composite Materials Stress Concentration Fracture Mechanics Friction Factor Laminates Crack Propagation Micromechanics Fatigue Tests Crack Bridging Stress Intensity Factors Titanium Shear Stress Metal Matrix Composites Thermal Stresses Residual Stress Crack Initiation Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
