本文選題：抗震設(shè)計(jì)　切入點(diǎn)：非線性分析　出處：《浙江大學(xué)》2014年博士論文

【摘要】：抗震鋼結(jié)構(gòu)的構(gòu)件截面通常要求其具有一定的塑性轉(zhuǎn)動(dòng)能力,實(shí)際工程中采用對(duì)截面進(jìn)行分類,并對(duì)每一類截面的板件規(guī)定相應(yīng)的寬厚比限值來滿足結(jié)構(gòu)的延性需求。目前常用的截面分類方法主要基于承載力和對(duì)達(dá)到承載力以后的變形能力的定性描述進(jìn)行的,沒有給出板件延性與寬厚比的關(guān)系,缺乏截面分類的具體定量指標(biāo)。 本文先對(duì)五種邊界條件的均勻受壓矩形板進(jìn)行考慮幾何非線性、材料非線性、殘余應(yīng)力、初始幾何缺陷的非線性分析,得到各模型的壓力—壓縮變形曲線,并取承載力下降15%處的變形作為計(jì)算板件壓縮延性從的依據(jù)。參數(shù)分析發(fā)現(xiàn)：不同分布模式的殘余應(yīng)力和殘余應(yīng)力幅值對(duì)μ。沒有明顯的影響；初始幾何缺陷幅值增大,μc。會(huì)降低,但降低的幅度不大。μc隨板件長寬比a/b的增加沒有簡單的單調(diào)增加或遞減關(guān)系,μc最大值出現(xiàn)在a/b使屈曲半波數(shù)為1的范圍,當(dāng)a/b增大到使屈曲半波數(shù)大于1之后,μc的變化不大。對(duì)比不同邊界條件的μc,當(dāng)非加載邊約束越強(qiáng),μc越高。按照從和通用寬厚比兄的關(guān)系,擬合了不同邊界條件的μc。計(jì)算公式。經(jīng)過驗(yàn)證,這組公式可適用于不同屈服強(qiáng)度的鋼材。 對(duì)受彎和壓彎狀態(tài)下的四邊簡支矩形板以及受彎翼緣板進(jìn)行彎矩—曲率分析,采用曲率定義受彎板件的延性,壓彎板件的延性除了用曲率定義之外還采用了板件邊緣纖維壓應(yīng)變來定義延性。通過分析發(fā)現(xiàn)板件邊緣纖維壓應(yīng)變定義的μbc1不小于曲率定義的μbc2,且在純彎情況下μbc1=μbc2,在純壓情況下μbc2=0,μbc1=μc。相同寬厚比的情況下,翼緣板受彎時(shí)的延性要遠(yuǎn)遠(yuǎn)大于受壓時(shí)的延性。根據(jù)計(jì)算結(jié)果,擬合了受彎和壓彎狀態(tài)下的四邊簡支矩形板及受彎翼緣板的延性計(jì)算公式。 為研究板件間相互作用對(duì)截面延性的影響,對(duì)壓彎荷載作用下的工字形截面和箱形截面模型進(jìn)行非線性分析,得到各模型的彎矩—曲率曲線,采用曲率定義截面延性。研究發(fā)現(xiàn)當(dāng)軸壓比一定時(shí),固定翼緣或腹板的寬厚比,降低另一板件的寬厚比,截面延性會(huì)增加。另外截面高寬比和翼緣板與腹板的厚度比對(duì)截面延性也有很大的影響,在腹板寬厚比和翼緣寬厚比相同的情況下,不同高寬比或板件厚度比的截面延性并不相同。對(duì)軸壓比在0-0.8之間的工形截面和箱形截面延性系數(shù)進(jìn)行公式擬合,得到了截面延性系數(shù)與通用寬厚比λ的簡潔關(guān)系式。 最后嘗試提出了面向抗震設(shè)計(jì)的鋼構(gòu)件截面分類方法。其出發(fā)點(diǎn)是：以計(jì)算地震力的結(jié)構(gòu)影響系數(shù)的大小來確定截面的分類。先根據(jù)結(jié)構(gòu)延性與截面延性的關(guān)系,區(qū)分考慮和不考慮結(jié)構(gòu)的超強(qiáng)系數(shù),反推出對(duì)各類截面的延性要求。然后利用前面得到的截面延性系數(shù)計(jì)算公式,按照各類截面的延性需求,分別給出各類截面的板件寬厚比分界。其中工字形截面和箱形截面的寬厚比分界采用了翼緣寬厚比和腹板寬厚比的相關(guān)關(guān)系來進(jìn)行表示,并擬合了相關(guān)關(guān)系的計(jì)算式。
[Abstract]:The cross section of aseismatic steel structure usually requires a certain plastic rotation capacity , and the cross section is classified according to the actual engineering , and the corresponding wide - thickness specific limit value is specified for each type of cross - section plate to meet the ductility demand of the structure . The commonly used sectional classification method is mainly based on the bearing capacity and the qualitative description of the deformation capacity after the bearing capacity is reached , and the relation between the ductility and the aspect ratio of the plate is not given , and the specific quantitative index of the cross - section classification is lacking .

In this paper , the nonlinear analysis of geometric nonlinearity , material nonlinearity , residual stress and initial geometric imperfections are taken into account for the uniform compression rectangular plates with five boundary conditions . The deformation curves of the pressure - compression deformation curves of each model are obtained , and the deformation at 15 % of the bearing capacity is taken as the basis for calculating the compression ductility of the plate .
When a / b increases to a range where the number of buckling half waves is greater than 1 , 渭c is not large . When a / b increases to make the number of buckling half waves greater than 1 , the higher the 渭 c is . When a / b increases to make the number of buckling half waves greater than 1 , the higher the 渭 c is . By comparison with the general aspect ratio , the higher the 渭 c is . By verification , the formula can be applied to steels with different yield strength .

The ductility of the flexural plate is defined by curvature . The ductility of the flexural plate is defined by curvature , and the ductility of the bending plate is defined by the curvature definition . In the case of pure bending , 渭bc1 = 渭bc2 , the ductility of the flange plate is much larger than that of the compression . According to the calculation results , the formulas for calculating the ductility of the four - sided simple rectangular plate and the bent flange plate under the condition of bending and bending are fitted .

In order to study the influence of the interaction of the plates on the ductility of the cross section , the I - shaped cross section and the box - shaped cross section model under the action of bending load are analyzed non - linear to obtain the bending moment - curvature curve of each model .

In the end , the section classification method for seismic design is proposed . The starting point is to determine the classification of section by calculating the structure influence coefficient of seismic force . Firstly , according to the relationship between structural ductility and section ductility , the ductility requirements of various sections are given .

【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TU391;TU352.11

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