冷軋不鏽鋼帽型斷面腹板之皺曲強度

Abstract

本研究旨在探討冷軋不鏽鋼帽型斷面於試體內部雙翼(Interior Two-Flange, ITF)受集中荷載之腹板皺曲強度與行為，共進行12支採用不同不鏽鋼板厚度及不同支承墊寬度之試體，試體均採用SUS 304型沃斯田不鏽鋼製作。試驗完成後進一步進行有限元素驗證分析，並與實驗結果互相比對以驗證分析之可靠度。最後進行參數研究，以54組不同條件之模型分析探討各參數對腹板皺曲強度的影響。實驗結果顯示，不鏽鋼板厚度及支承墊寬度的增加能有效的提升試體腹板皺曲強度。實驗結果與規範計算值比較，發現北美洲規範(NAS)與美國土木工程協會(ASCE)規範於腹板皺曲強度的計算上吻合實驗結果，然而歐洲規範(EC3)則偏向保守。有限元素分析結果能有效模擬試驗結果與行為。參數研究發現除了增加不鏽鋼板厚度及支承墊寬度外，腹板平坦段高度的減少亦能提高腹板皺曲強度；此外，腹板皺曲強度受到腹板平坦段高度的影響程度會隨著支承墊寬度的減小而降低。

This study aims to investigate web crippling strength of single hat sections of stainless steel under the interior two-flange (ITF) loading condition. Twelve specimens, made of austenitic type 304 stainless steel, were designed to have different web thickness and support width. Finite element analysis was further performed to validate the analytic model by comparing the analysis results with test data. Furthermore, parametric study was conducted to study the effect of parameters on the web crippling strength. Test results demonstrated that increasing the thickness and support width resulted in increase of the web crippling strength. In addition, the comparison of the test results with various codes indicated the codes of North American Specification and American Society of Civil Engineering calculated well the web crippling strength except that Eurocode highly overestimated. Results of finite element analysis showed that either the web crippling strength or crippling behavior of the analysis agreed well with test results. Parametric study indicated that decreasing the flat height of the web can also increase the web crippling strength, in addition to the increase of the thickness and support width. Moreover, the effect of flat height of the web on the web crippling strength will be reduced when the support width decrease.