https://scholars.lib.ntu.edu.tw/handle/123456789/169469
標題: | 降伏厚面開關機制之理論實驗與應用(2/2) | 作者: | 洪宏基 | 關鍵字: | switching mechanism;two alternative phases;complementary trio;yield thick-surface;transcritical bifurcation;elastoplasticity;friction | 公開日期: | 2005 | 出版社: | 臺北市:國立臺灣大學土木工程學系暨研究所 | 摘要: | The project was proposed to study mechenisms of switching, with the aim of applying to switching between plastic and elastic phases in the problem of elastoplastic constitutive modeling and switching between sliding and sticking in the problem of vibration control by friction. The focus is on the switching mechanism associated with a yield thick-surface, but other feasible approaches such as multiple complementary trios and transcritical bifurcation are also explored. In particular, a variety of aspects of so-called complementary trios and variants are investigated. In order to deal with the problems that the models with a conventional yield surface tend to predict a loop of stress-strain curve which is over square in reverse loading and whose back stress is over oscillatory in cyclic loading, we generalize a complementary trio to multiple complementary trios, furthermore to a continuum of complementary trios. When associated with a yield surface a complementary trio acts as a switching mechanism of single yield surface. By analogous association, the multiple complementary trios thus act as a multiple yield surface switching mechanism, and the complementary trio continuum a distributed yield surface switching mechanism. Alternatively, we may thicken the yield surface so that the plastic-phase constitutive equations can develop their capabilities in more ample space in stress space. To remedy the loss of consistency condition due to the thickening, the yield thick-surface must be associated with a switching mechanism different from that associated with the conventional zero-thickness yield surface. Referring to the state and output equations in control dynamical system theory, we obtain a general system of equations for elastoplatic evolution and state, which embrace most ingredients of elastoplasticity such as elastic relations, elastic-plastic decomposition, plastic flow, hardeningsoftening, etc. The significance of doing so is that the constitutive theory of elastoplasticity thus has a clear relation with the theories of control dynamic systems and nonlinear ordinary differential equations. On the basis of the latter we can deepen our research on plasticity. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/2889 | 其他識別: | 932211E002016 | Rights: | 國立臺灣大學土木工程學系暨研究所 |
顯示於: | 土木工程學系 |
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932211E002016.pdf | 3.89 MB | Adobe PDF | 檢視/開啟 |
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