sectional bar 中文意思是什麼
sectional bar
解釋
型材-
Reasons : firstly, sectional dimension is so little that torsional stiffness of single - beam is n ' t enough. secondly, protective layer thickness is too thin to protect concrete reinforced bar and reduce durability. lastly, each main beam is joined by cross girder and the more rigid of cross girder the more entirety of bridge
橋梁局部損壞較嚴重，主要原因是主梁截面尺寸過小、肋板過于薄弱，造成單梁抗扭剛度不足；保護層厚度不夠導致鋼筋外露引起銹蝕，降低了橋梁的耐久性；各主梁採用橫隔梁連接成整體，橫隔梁的剛度越大，橋梁的整體性越好，但調查結果顯示，實際情況中並不能達到理想的整體剛度。 -
Support with binding bar, bolting and shotcrete for large cross - sectional chamber in fractured zone
破碎帶大斷面硐室綁筋錨噴支護 -
For shape optimization of truss structure, the design variables are separated into two kinds of bar sectional size and nodal position by multilevel decomposition optimization method
對于桁架結構形狀優化，應用層次分解優化方法，將設計變量分成桿件截面積和節點位置兩類變量。 -
The use of high strength concrete in building constructions has many advantages, such as reducing sectional size of component evidently, alleviating the structure self weight and retrenchment the use of reinforcing steel bar, thus the economic benefit is distinct but the brittleness of high strength concrete causes anxious about its use in the earthquake - resistant structure
應用高強混凝土可以顯著減小構件的截面尺寸，減輕結構自重和鋼筋用量，具有明顯優點，可獲得較高的經濟效益。但高強混凝土的脆性引起人們對其用於抗震結構的擔心，強度等級愈高，胞性愈大。 -
The bar sectional sizes are optimized to make the weight of the structure minimized under constraints of stress, displacement and local stability. at the second step, supposing the active displacement constraints of the first step keeping unchanged. a quadratic programming model that increases the structural rigidity is solved
求解時分為兩層，第一層在給定節點位置下對桿件截面進行優化，同時考慮了應力、局部穩定約束和位移約束的重量最輕；第二層假定截面層的有效位移約束作用不變，求解一個使桁架剛度增強的二次規劃問題，獲得既不違反約束，又使目標函數不上升的新的節點位置，再返回第一層。 -
Second, to solve the local stability problem of the bar under pressure, a function relationship between the sectional area and the inertia moment is established by using the similar transformation. accounting to the critical pressure stress, iterative formulas are derived which include big, middle and small flexible degree
其次，對于桁架結構中受壓桿件的失穩破壞，本文提出採用相似變換方法找到截面積與慣性矩的關系，根據壓桿的臨界應力分別導出大、中、小柔度的迭代公式，設計出壓桿的截面積。 -
The optimal model of truss structure is established, in which the cross sectional areas of bar are taken as design variables, the structure weight is taken as objective function. in the process, the reliability of structural displacement and bar stress and the fundamental frequency are taken as constraint functions. from the engineering practice, all the reliability constraints, which are implicit generally with the design variables, are equalized and transferred to the conventional explicit constraints
本文將主要考慮桁架結構的優化問題，首先建立數學模型，即以桁架的橫截面積為設計變量、以重量最小為優化目標，位移、應力等可靠性及基頻為約束條件；最後，從工程實際出發，對結構系統的可靠性隱形約束進行等價顯化處理，使之轉化為常規的橫截面積優化問題。
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