薄壁箱梁剪力滯效應(yīng)分析

1、湖南大學(xué)土木工程學(xué)院高等橋梁結(jié)構(gòu)理論作業(yè)3一、題目采用有限元方法對(duì)教材P31頁(yè)算例進(jìn)行計(jì)算，具體分兩個(gè)工況進(jìn)行：（1）跨中截面腹板位置作用一對(duì)對(duì)稱集中豎向荷載，荷載大小為P/2=225.5KN；（2）跨中截面腹板位置作用一對(duì)反對(duì)稱集中豎向荷載，荷載大小為P/2=225.5KN。分別計(jì)算跨中截面、1/4跨位置截面上的正應(yīng)力和剪應(yīng)力分布，并繪制相應(yīng)的正應(yīng)力和剪應(yīng)力分布曲線。二、基本資料橋梁類型：預(yù)應(yīng)力混凝土等截面簡(jiǎn)支箱梁計(jì)算跨徑：L0=40m 混凝土：C40剪切模量：G=1.445×104MPa彈性模量：E=3.40×104MPa分析方法：ANSYS軟件命令流法三、ANSYS命

2、令流分析（1）工況一（對(duì)稱集中荷載）命令流finish/clear/title,the analysis of simply supported box-girder!*前處理模塊* /prep7!建立幾何模型k,1,0,0,0k,2,0,0,2.4k,3,0,0,7.1k,4,0,0,9.5k,5,0,-2.12,2.4k,6,0,-2.12,7.1kgen,2,all,40a,1,2,8,7a,2,3,9,8a,3,4,10,9a,6,5,11,12a,5,2,8,11a,3,6,12,9!定義單元屬性et,1,shell63r,1,0.22r,2,0.34r,3,0.30mp,ex,1,

3、3.40e10 !彈性模量mp,gyz,1,1.445e10 !剪切模量!賦予相應(yīng)的單元屬性和材料特性aatt,1,1,1,1aatt,1,1,1,2aatt,1,1,1,3aatt,1,2,1,4aatt,1,3,1,5aatt,1,3,1,6!網(wǎng)格劃分mshape,0,2d !采用四邊形網(wǎng)格mshkey,1 !采用映射網(wǎng)格esize,0.40amesh,allfinish!*求解模塊*/soluantype,static!在跨中腹板位置施加集中荷載allself,node(20,0,2.4),fy,-225500f,node(20,0,7.1),fy,-225500!邊界條件allseld

4、k,5,ux,uy,uz,rotydk,6,ux,uy,rotydk,11,uy,uz,rotydk,12,uy,rotysbctran !把實(shí)體單元模型的荷載和邊界條件，轉(zhuǎn)化到有限元幾何模型中solvefinish!*后處理模塊*/post1!查看梁的變形allselpldisp,2!查看跨中截面正應(yīng)力allsel nsel,s,loc,x,19.79,20.01esln,splnsol,s,x!路徑方法得到跨中截面正應(yīng)力分布曲線和數(shù)據(jù)path,zengyingli_a,2,50ppath,1,20,0,0ppath,2,20,0,9.5pdef,sx,s,xplpath,sxpath,ze

5、ngyingli_b,2,50ppath,1,20,0,0ppath,2,20,0,9.5pdef,sx,s,xprpath,sx!查看跨中截面剪應(yīng)力allsel nsel,s,loc,x,19.79,20.01esln,splnsol,s,xy!路徑方法得到跨中截面剪應(yīng)力分布曲線和數(shù)據(jù)path,jianyingli_a,2,50ppath,1,20,0,0ppath,2,20,0,9.5pdef,sxy,s,xyplpath,sxypath,jianyingli_b,2,50ppath,1,20,0,0ppath,2,20,0,9.5pdef,sxy,s,xyprpath,sxy!查看1/4

6、跨截面正應(yīng)力allsel nsel,s,loc,x,9.79,10.01esln,splnsol,s,x!路徑方法得到1/4跨正應(yīng)力分布曲線和數(shù)據(jù)path,zengyingli_a,2,50ppath,1,10,0,0ppath,2,10,0,9.5pdef,sx,s,xplpath,sxpath,zengyingli_b,2,50ppath,1,10,0,0ppath,2,10,0,9.5pdef,sx,s,xprpath,sx!查看1/4跨截面剪應(yīng)力allsel nsel,s,loc,x,9.79,10.01esln,splnsol,s,xy!路徑方法得到1/4跨截面剪應(yīng)力分布曲線和數(shù)據(jù)p

7、ath,jianyingli_a,2,50ppath,1,10,0,0ppath,2,10,0,9.5pdef,sxy,s,xyplpath,sxypath,jianyingli_b,2,50ppath,1,10,0,0ppath,2,10,0,9.5pdef,sxy,s,xyprpath,sxy根據(jù)以上命令流分析提取工況一情況下簡(jiǎn)支梁模型、正應(yīng)力分布、剪應(yīng)力分布如圖1-11-5所示。圖1-1 箱梁模型圖1-2 跨中截面正應(yīng)力分布圖圖1-3 跨中截面剪應(yīng)力分布圖圖1-4 1/4跨截面正應(yīng)力分布圖圖1-5 1/4跨截面剪應(yīng)力分布圖（2）工況二（反對(duì)稱集中荷載）命令流在工況一和工況二情況下，荷載作

8、用位置相同，只是荷載的作用方向不同，故在工況二條件下的ANSYS命令流與工況一類似，只需把荷載定義部分作以下修改即可（其余命令流不變）：!在跨中腹板位置施加集中荷載allself,node(20,0,2.4),fy,-225500f,node(20,0,7.1),fy,225500根據(jù)以上命令流分析提取工況一情況下簡(jiǎn)支梁模型、正應(yīng)力分布、剪應(yīng)力分布如圖2-12-5所示。圖2-1 箱梁模型圖2-2 跨中截面正應(yīng)力分布圖圖2-3 跨中截面剪應(yīng)力分布圖圖2-4 1/4跨截面正應(yīng)力分布圖 圖2-5 1/4跨截面剪應(yīng)力分布圖四、兩種工況對(duì)應(yīng)的正、剪應(yīng)力分布曲線（1）工況一（對(duì)稱集中荷載）應(yīng)力分布曲線 、 跨中截面正應(yīng)力分布 、 跨中截面剪應(yīng)力分布 、1/4跨截面正應(yīng)力分布： 、1/4跨截面剪應(yīng)力分布 （2）工況二（反對(duì)稱集中荷載）應(yīng)力分布曲線 、 跨中截面正應(yīng)力分布 、 跨中截