Endochronic Viscoplasticity with Fatigue Damage of Sn/3.5Ag/0.75Cu Solder Joints under Cyclic Mixed-Mode Loading
| Autor: | Hung-Yi Lin, 林紘毅 |
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| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 In this paper, experimental data of Ohguchi et. al. are used to extend the Endochronic cyclic viscoplasticity of eutectic Tin/Lead(60/40) solder alloy by Lee and Shieh to a Lead-free material of Sn/3.5Ag/0.75Cu; Employed the experimental stress-strain hysteresis loops of different strain rates, material parameters and material functions in the theory can be determined and the functional form of strain rate sensitivity can also be established. Park et. al. used cyclic mixed-mode loading tests on Sn/3.5Ag/0.75Cu solder joints and investigated their degree of cyclic damage. In the Endochronic theory, the accumulation of intrinsic time is proposed first to depend on the loading angle and then cubic symmetric material parameters and material functions are determined. Through previous experiment, relationships of axial and shear damage factor with cycle number can be established. Using Lemaitre’s strain equivalence principle in the endochronic constitutive equation with damage factor, force-displacement response under cyclic mixed-mode loading can be computed. The hysteresis loops computed under 20％、50％ and 70％ load drop are in very good agreement with data. These allow the discussion in the critical values of damage factor under different loading angles. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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