Plastic buckling of multi-layered beams /
| Main Author: | |
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| Other Authors: | , , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
[College Station, Tex.] :
Iwamura,
1976.
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| Subjects: | |
| Online Access: | Link to ProQuest copy Link to OAKTrust copy |
| Abstract: | Previous experimental folding of single beams of Indiana limestone provides stress-strain curves ana evidence of buckling instability. These experimental results provide the general information needed to make incremental analyses using the finite element technique. The solutions of material and geometrical nonlinear beam problems /have been achieved. Computer simulation using elastic-plastic rheology yields a good approximation of the experimental results, for single beams. Therefore, it is assumed that the method for the single layer case can be extended to multiple layers of elastic-plastic material. Simulations are made with Young's modulus of 10⁵, 7.5 X 10⁴, and 5 X 10⁴ kg/cm², Poisson's ratio of 0.25, yield stress of 500 kg/cm², tangent modulus of 5 X 10⁴ kg/cm², and simply supported end-conditions. The plastic zone grows outward from the bottom center of the layer, (fold viewed as an anticline). At the crest of the fold the orientation of the maximum compressive stress changes from parallel to perpendicular to the beam with increased deformation. Two kinds of instability are defined; a geometrical instability and a material instability. For the geometrical instability, the deflection at the center of the beam grows considerably with a small increase in axial loads, but once the material stability occurs, a large deflection can take place under decreasing incremental axial load, and the beam becomes shorter. For large deflection the growth of the plastic zone and the orientation of principal stresses are nearly the same for both single and multiple layered folds. |
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| Item Description: | "Major subject: Geophysics." Vita. |
| Physical Description: | xiii, 145 leaves : illustrations ; 28 cm |
| Bibliography: | Includes bibliographical references (leaves 102-113). |