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Simplified micromechanical equations for thermal residual stress analysis of coated fiber composites
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Naik, R. A. |
| Copyright Year | 1991 |
| Description | The fabrication of metal matrix composites poses unique problems to the materials engineer. The large thermal expansion coefficient (CTE) mismatch between the fiber and matrix leads to high tensile residual stresses at the fiber/matrix (F/M) interface which could lead to premature matrix cracking during cooldown. Fiber coatings could be used to reduce thermal residual stresses. A simple closed form analysis, based on a three phase composite cylinder model, was developed to calculate thermal residual stresses in a fiber/interphase/matrix system. Parametric studies showed that the tensile thermal residual stresses at the F/M interface were very sensitive to the CTE and thickness of the interphase layer. The modulus of the layer had only a moderate effect on tensile residual stresses. For a silicon carbide titanium aluminide composite, the tangential stresses were 20 to 30 pct. larger than the axial stresses, over a wide range of interphase layer properties, indicating a tendency to form radial matrix cracks during cooldown. Guidelines for the selection of appropriate material properties of the fiber coating were also derived in order to minimize thermal residual stresses in the matrix during fabrication. |
| File Size | 789088 |
| Page Count | 28 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19910023213 |
| Archival Resource Key | ark:/13960/t0ns5nv50 |
| Language | English |
| Publisher Date | 1991-09-01 |
| Access Restriction | Open |
| Subject Keyword | Structural Mechanics Axial Stress Stress Analysis Silicon Carbides Fiber Composites Coatings Aluminides Micromechanics Fabrication Thermal Expansion Tensile Stress Fiber-matrix Interfaces Titanium Metal Matrix Composites Thermal Stresses Residual Stress 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 |
