柱及殼結構之常溫潛變挫屈行為

Creep Buckling of Column and Shell Structures at Room Temperature

蘇庭鋒(Ting-Feng Su)

指導教授 ： 葉孟考

國立清華大學/工學院/動力機械工程學系/碩士(2006年)

摘要

本文主要在研究柱及殼結構在常溫下的潛變挫屈行為。在實驗方面，先以單軸拉伸實驗測量材料的常溫機械性質，並設計一組設備測量材料在不同應力作用下的潛變行為，再以應變硬化方程式(Strain-hardening equation)與修正型時間硬化方程式(Modified time-hardening equation)描述材料的潛變行為。在分析方面，以有限單元分析軟體ANSYS分析柱及殼結構之潛變挫屈變形行為及臨界時間。結果顯示，紅銅材料在常溫有明顯之暫態潛變行為，且受到的負載愈大，潛變行為愈明顯；以應變硬化方程式和修正型時間硬化方程式可以合理地描述紅銅之潛變行為；以ANSYS分析殼結構受側向壓力之結果與文獻記載相符；柱體受到的負載愈大則發生潛變挫屈的時間愈短；柱與殼結構之潛變挫屈行為對於幾何不完美十分敏感。

關鍵字

潛變挫屈 ； 有限單元分析 ； 臨界時間

並列摘要

The creep buckling behavior of column and shell structures at room temperature was investigated. In experiment, the mechanical properties of test structures were measured by tensile test. An experimental setup was designed to measure the material creep behavior at different stress levels. The material creep behavior is described by the strain-hardening equation and modified time-hardening equation. In analysis, the creep deformation and the corresponding critical time at creep buckling for column and shell structures were analyzed by finite element code ANSYS. The results showed that copper had apparent transient creep behavior, and copper deformed more for higher loading. The creep behavior of copper can be described well by the strain-hardening equation and modified time-hardening equation. The analytical results of critical time at creep buckling for columns became shorter as higher loading was applied. The creep buckling behavior of column and shell structures are very sensitive to geometry imperfection.

並列關鍵字

Creep buckling ； Finite element analysis ； Critical time

參考文獻

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