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FEM Analysis of the Effects of Geometric Parameters on the Superplastic Forming of Metal Matrix Composit

Tehrani, Mehdi | 2009

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39807 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Abedian, Ali
  7. Abstract:
  8. In aerospace applications, the weight of structures is considered as a major performance parameter. One of the most effective ways for weight reduction is then attributed to the structurally continuous manufacturing of mechanical components. In this way, not only the weight, but also the stress concentration, the cost, joints and fasteners applications, and the time of manufacturing are noticeably reduced. With this method, components with complicated shapes could be formed in a single manufacturing step. Special specification of whisker reinforced Metal Matrix Composites (MMC’s) has made these materials very attractive for the aerospace applications.That is why the superplastic forming of materials has been found a considerable attention. In recent years, some experimental attempts have been made to extend the borders of superplasticity science to promote superplastic characteristic of MMC’s. But, a few numerical studies would be found on the simulation of the superplastic process. In the present study it is tried to highlight the difficulties involves with the FEM modeling of superplasticity in MMC’s. An axisymmetric micromechanical finite element model as well as a 3D model has been developed to predict the superplastic behavior of MMC’s. In particular, in this study the superplasticity behavior of Al2024/SiCw is investigated as a typical MMC and the results obtained from the FE modeling are compared with some available experimental data. Some manufacturing defects, changing material properties with temperature, and also geometrical aspects such as Fiber’s overlapping ratio and debonding which are involved in plastic strain of the MMC are considered to improve the results of the modeling. The results of this simulation work are very promising and have shown a reasonable agreement with the experimental results available on the ISS tests and strain-rate-sensitivity data. Specially, the strain rate vs. applied stress diagrams obtained from the simulation and experiments show an acceptable correlation
  9. Keywords:
  10. Axisymmetric Model ; Three Dimensional Model ; Overlapping ; Superplasticity ; Metal Matrix Composite (MMC) ; Interface Debonding

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