hemispherical head 中文意思是什麼
hemispherical head
解釋
半球形封頭- hemispherical : adj. 半球的。
- head : n 1 頭，頭部，首。2 頭腦，才能；智力，想像力，理解力。3 前部，上部；頂端，尖突部；船長；（書頁等...
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Author thinks that the direction of the maximum plastic distortion along a constant radius around the crack tip may be considered as the direction of shear - mode fracture ( named pmax - criterion ) and the load when located shear band prongs the ligament in the front of crack tip is regarded as the limited load of shear - mode fracture. ( 3 ) the fad ( fracture assessment diagram ) of titled crack is proposed based on achievements of mesomechanics about i - ii complex ductile fracture of metal, and the titled crack is classified two kinds : void - mode fracture is assessed by fracture assessment curve, and shear - mode fracture by limited load. ( 4 ) using a fe program based on plantle - ressue theory to calculate some mesomechanical parameters, a flange joint structure of a high pressure vessel ( design pressure 31. 4mpa and the thickness of the hemispherical head is half of that of shell. ) is analyzed to determine whether the structure under operation pressure is safe or not, forecast the mode of potential invalidation and argue for the rationality of design of the structure
試件的整體斷裂為剪切型，但在試件芯部裂尖鈍化區中部出現了韌窩型啟裂並有一定的擴展，說明局部較高的應力三軸度也會使韌窩型機制得以發展，但是不改變試件整體的剪切型斷裂模式；對韌性斷裂的剪切模式的細觀機理做了一定的探討，並且提出了含裂紋構件剪切型斷裂的宏觀判據：認為裂紋前方的集中剪切帶中與裂紋尖端等半徑處最大有效塑性應變出現的方向可以作為裂紋剪切斷裂的方向（可簡稱為_ （ pmax ）準則） ，集中剪切滑移帶貫穿裂紋前方承載韌帶時的載荷可以作為極限載荷；本文運用金屬韌性斷裂細觀力學在一復合型韌性斷裂方面的研究成果，採用失效評定圖的形式，提出了傾斜裂紋的安全性評定方法的基本框架。 -
16mnr and 45 # steel are taken as examples. the obtained results have been applied to analyze the safety of operation pressure and rationality of design of a kind of engineering structure - a flange joint of hemispherical head to cylindrical shell. try to seek a sort of new method to assessment the capability of structure to load beyond the traditional method which regards stress and strain as main parameters
本文以45 ~ #調質鋼和壓力容器常用鋼材16mnr為研究對象，對金屬材料韌性斷裂的斷裂模式進行細觀機理上的研究，進而分析一種工程結構? ?採用與筒體厚度不同的半球形封頭的壓力容器的筒體連接結構? ?的靜載變形特點和破壞形式，嘗試在以應力應變為主要參數的傳統方法之外，尋求一種新的結構承載能力分析的方法。
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