64m钢桁架铁路桥内力分析.docx
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64m钢桁架铁路桥内力分析.docx
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64m钢桁架铁路桥内力分析
Ansys课程设计
一、任务说明书
以64m双线铁路栓焊下承桁梁为研究对象,利用ansys建模分析该钢桁桥在各种工况作用下的变形和强度,验证其设计的合理性。
该桥采用TBJ2-85铁路桥涵设计规范进行设计,铁路列车竖向活载为"中-活载",钢梁主体结构采用16Mnq,高强度螺栓采用20MnTiB(螺帽及垫圈用45号钢)。
该桥的设计轮廓图分别如图1、图2和图3所示。
图1上平纵联
图2主桁
图3下平纵联
二、概述
Ansys建模采用自底向上的实体建模,即先定义关键点,然后在关键点的基础上连接成线,之后在初步形成的图形上划分网格,生成节点和单元,并定义截面类型,即可得到有限元模型。
由于本人是通过文本命令流建模,出于单元编号的有序性考虑,本文没有选择先建立半桥模型然后对称映像成全桥模型,而是直接建立全桥模型。
模型的简化:
1.各杆件连接简化为刚接2.桥门架结构省略3.活载按中—活载平均后均布加载
文本命令流的主要顺序:
1.定义单元属性:
a.单元类型:
本文所有杆件均采用beam44。
对beam44的简要介绍:
单轴单元,具有抗拉、抗压、抗扭、抗弯能力;有六个自由度;允许节点偏离形心;仅适合处理线性问题。
而本设计只要求结构在静力荷载下的反应,线性单元就已满足要求。
允许节点偏离形心使我们可以在设置截面属性时就可解决实际结构各杆件连接处形心不重合问题,所以选用beam44非常合适。
B.材料属性:
刚材的属性为
,
,
。
C.截面属性:
共定义定义了13种横截面形式,为解决实际结构各杆件连接处形心不重合问题,我们假设各单元连接处形心重合,但定义的形心偏离实际形心,即自定义截面形心。
2.生成实体模型。
按点、线的顺序生成。
考虑到后处理时,分别对横梁、纵梁、桁架进行分析,所以点线编号也按此顺序进行。
3.划分单元。
本文中按1米的间隔划分单元,,一共得到了1410个单元、2704个节点。
划分单元的注意点:
定义梁截面的方向时,是在局部坐标系下定义的,通过定义第三个参考点k与I、J确定一个平面,即为x-z平面,I到J代表x轴,z轴的方向与k点相近,y轴由右手定则的出。
所以在划分单元时,对每个线都定义了参考点。
4.施加荷载
1.约束:
模型的位移约束均加在下弦杆的四个关键点上,其中一个空间固定铰支座、两个平面固定铰支座、一个活动铰支座。
2.荷载
本文定义了五种荷载工况,各荷载工况如下:
工况一:
恒载(通过y设置加速度9.8N/kg)
工况二:
恒载+全桥满布;
工况三:
恒载+同侧半桥满布;
工况四:
自恒载重+全桥单线;
工况五:
恒载+异侧半桥满布。
其中恒载包括自重和二恒,自重加速度为:
9.8N/㎏,二恒为枕木荷载:
2t/线/m。
根据“中-活载”得到的线均布荷载为:
本文实际加载时,活载按工况单独加载,并没有与恒载一起作用,得出数据后,再自己叠加。
三、Ansys模型的建立与求解
3.1有限元建模及网格划分(前处理)
3.1.1选择单元属性
/title,asimplebridge
/prep7
ET,1,BEAM44!
定义单元类型
mp,ex,1,210e9!
定义材料
mp,prxy,1,0.3
mp,dens,1,7850
SECTYPE,1,BEAM,HREC,rsc1,1!
定义截面
SECOFFSET,CENT
SECDATA,0.62,0.46,0.016,0.016,0.020,0.020,0,0,0,0
SECTYPE,2,BEAM,I,vc2,1
SECOFFSET,user,0,0.23
SECDATA,0.42,0.42,0.46,0.016,0.012,0.01,0,0,0,0
SECTYPE,3,BEAM,I,lsc3,1
SECOFFSET,CENT
SECDATA,0.46,0.46,0.46,0.02,0.02,0.016,0,0,0,0
SECTYPE,4,BEAM,HREC,rcs4,1
SECOFFSET,CENT
SECDATA,0.46,0.46,0.012,0.012,0.012,0.012,0,0,0,0
SECTYPE,5,BEAM,I,lsc5,1
SECOFFSET,CENT
SECDATA,0.46,0.46,0.46,0.016,0.016,0.01,0,0,0,0
SECTYPE,6,BEAM,I,6,0
SECOFFSET,CENT
SECDATA,0.600,0.600,0.460,0.016,0.016,0.012,0,0,0,0
SECTYPE,7,BEAM,I,7,0
SECOFFSET,CENT
SECDATA,0.600,0.600,0.460,0.024,0.024,0.020,0,0,0,0
SECTYPE,8,BEAM,I,8,0
SECOFFSET,CENT
SECDATA,0.6,0.6,0.46,0.032,0.032,0.024,0,0,0,0
SECTYPE,9,BEAM,I,upp9,0
SECOFFSET,CENT
SECDATA,0.3,0.3,0.42,0.01,0.01,0.01,0,0,0,0
SECTYPE,10,BEAM,I,ups,0
SECOFFSET,CENT
SECDATA,0.23,0.23,0.42,0.01,0.01,0.01,0,0,0,0
SECTYPE,11,BEAM,I,dowp11,0
SECOFFSET,USER,0,1.67
SECDATA,0.38,0.27,1.97,0.032,0.032,0.016,0,0,0,0
SECTYPE,12,BEAM,I,does12,0
SECOFFSET,cent
SECDATA,0.23,0.23,0.42,0.01,0.01,0.01,0,0,0,0
SECTYPE,13,BEAM,I,longi13,0
SECOFFSET,user,0,1.67
SECDATA,0.24,0.24,1.29,0.016,0.016,0.01,0,0,0,0
3.1.2定义关键点、线
*do,j,1,9,1!
生成横梁关键点
k,j,(j-1)*8,0,0
*enddo
*do,j,1,9,1
k,j+9,(j-1)*8,0,-1.866
*enddo
*do,j,1,9
k,j+18,(j-1)*8,0,-3.866
*enddo
*do,j,1,9
k,j+27,(j-1)*8,0,-5.866
*enddo
*do,j,1,9
k,j+36,(j-1)*8,0,-7.866
*enddo
*do,j,1,9
k,j+45,(j-1)*8,0,-9.732
*enddo
*do,j,1,8!
生成纵梁线1~32
l,j+9,j+10
*enddo
*do,j,1,8
l,j+18,j+19
*enddo
*do,j,1,8
l,j+27,j+28
*enddo
*do,j,1,8
l,j+36,j+37
*enddo
*do,j1,1,9!
生成横梁线33~77
*do,j,1,5
l,j1+(j-1)*9,j1+j*9
*enddo
*enddo
*do,j,1,8!
生成下弦杆86~93
l,j,j+1
*enddo
*do,j,1,8
l,j+45,j+46
*enddo
*GET,dian1,kp,,NUM,MAX!
生成上弦杆dian55~61,x94~99
*do,j,1,7
k,dian1+j,j*8,11,0
*enddo
*do,j,1,6
l,dian1+j,dian1+j+1
*enddo
*do,j,1,7!
生成腹杆100~106
l,j+1,j+54
*enddo
*do,j,1,4!
生成腹杆107~114
l,j*2-1,j*2+53
l,j*2+53,j*2+1
*enddo
*GET,dian2,kp,,NUM,MAX!
生成上弦杆115~120
*do,j,1,7
k,dian2+j,j*8,11,-9.732
*enddo
*do,j,1,6
l,dian2+j,dian2+j+1
*enddo
*do,j,1,7!
生成腹杆121~127
l,j+46,j+61
*enddo
*do,j,1,4!
生成斜腹杆128~135
l,j*2+44,j*2+60
l,j*2+60,j*2+46
*enddo
*do,j,1,8!
生成下平联杆中点69~76
k,68+j,8*j-4,0,-4.866
*enddo
*do,j,1,8!
生成下平联杆136~151
l,j,j+68
l,j+68,j+46
*enddo
*do,j,1,8!
生成下平联杆152~167
l,45+j,68+j
l,68+j,1+j
*enddo
*do,j,1,6!
生成上平联杆中点77~82
k,76+j,8*j+4,11,-4.866
*enddo
*do,j,1,6!
生成上平联杆168~179
l,j+54,j+76
l,j+76,j+62
*enddo
*do,j,1,6!
生成下平联杆180~191
l,61+j,76+j
l,76+j,55+j
*enddo
*do,j,1,7!
生成上平直杆192~198
l,54+j,61+j
*enddo
3.1.3分配单元属性、网格划分
*get,dian3,kp,,num,max!
mesh纵梁
k,dian3+1,0,-2,-1.866
lsel,s,line,,1,8
LATT,1,,1,,dian3+1,,13
LESIZE,ALL,1
LMESH,ALL
*get,dian3,kp,,num,max
k,dian3+1,0,-2,-3.866
lsel,s,line,,9,16
LATT,1,,1,,dian3+1,,13
LESIZE,ALL,1
LMESH,ALL
*get,dian3,kp,,num,max
k,dian3+1,0,-2,-5.866
lsel,s,line,,17,24
LATT,1,,1,,dian3+1,,13
LESIZE,ALL,1
LMESH,ALL
*get,dian3,kp,,num,max
k,dian3+1,0,-2,-7.866
lsel,s,line,,25,32
LATT,1,,1,,dian3+1,,13
LESIZE,ALL,1
LMESH,ALL
*do,j1,1,9!
mesh横梁线33~77
*get,dian3,kp,,num,max
k,dian3+1,8*(j1-1),-2,0
lsel,s,line,,28+j1*5,32+j1*5
LATT,1,,1,,dian3+1,,11
LESIZE,ALL,1
LMESH,ALL
*enddo
*get,dian3,kp,,num,max
k,dian3+1,-8,0,-11
lsel,s,line,,78!
mesh下弦杆
LATT,1,,1,,dian3+1,,6
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,79,80!
mesh下弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,81!
mesh下弦杆
LATT,1,,1,,dian3+1,,8
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,82!
mesh下弦杆
LATT,1,,1,,dian3+1,,8
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,83,84!
mesh下弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,85!
mesh下弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,86!
mesh下弦杆
LATT,1,,1,,dian3+1,,6
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,87,88!
mesh下弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,89!
mesh下弦杆
LATT,1,,1,,dian3+1,,8
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,90!
mesh下弦杆
LATT,1,,1,,dian3+1,,8
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,91,92!
mesh下弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,93!
mesh下弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
*get,dian3,kp,,num,max
k,dian3+1,-8,11,-11
lsel,s,line,,94,95!
mesh上弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,96,97!
mesh上弦杆
LATT,1,,1,,dian3+1,,8
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,98,99!
mesh上弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
k,dian3+1,-8,11,-11
lsel,s,line,,115,116!
mesh上弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,117,118!
mesh上弦杆
LATT,1,,1,,dian3+1,,8
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,119,120!
mesh上弦杆
LATT,1,,1,,dian3+1,,7
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,107!
mesh斜腹杆
LATT,1,,1,,62,,1
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,108!
mesh斜腹杆
LATT,1,,1,,62,,3
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,109!
mesh斜腹杆
LATT,1,,1,,64,,4
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,110!
mesh斜腹杆
LATT,1,,1,,64,,5
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,111!
mesh斜腹杆
LATT,1,,1,,66,,5
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,112!
mesh斜腹杆
LATT,1,,1,,66,,4
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,113!
mesh斜腹杆
LATT,1,,1,,68,,3
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,114!
mesh斜腹杆
LATT,1,,1,,68,,1
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,128!
mesh斜腹杆
LATT,1,,1,,55,,1
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,129!
mesh斜腹杆
LATT,1,,1,,55,,3
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,130!
mesh斜腹杆
LATT,1,,1,,57,,4
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,131!
mesh斜腹杆
LATT,1,,1,,57,,5
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,132!
mesh斜腹杆
LATT,1,,1,,59,,5
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,133!
mesh斜腹杆
LATT,1,,1,,59,,4
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,134!
mesh斜腹杆
LATT,1,,1,,61,,3
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,135!
mesh斜腹杆
LATT,1,,1,,61,,1
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,100!
mesh直腹杆
LATT,1,,1,,62,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,101!
mesh直腹杆
LATT,1,,1,,63,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,102!
mesh直腹杆
LATT,1,,1,,64,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,103!
mesh直腹杆
LATT,1,,1,,65,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,104!
mesh直腹杆
LATT,1,,1,,66,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,105!
mesh直腹杆
LATT,1,,1,,67,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,106!
mesh直腹杆
LATT,1,,1,,68,,2
LESIZE,ALL,1
LMESH,ALL
!
lsel,s,line,,121!
mesh直腹杆
LATT,1,,1,,55,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,122!
mesh直腹杆
LATT,1,,1,,56,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,123!
mesh直腹杆
LATT,1,,1,,57,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,124!
mesh直腹杆
LATT,1,,1,,58,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,125!
mesh直腹杆
LATT,1,,1,,59,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,126!
mesh直腹杆
LATT,1,,1,,60,,2
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,127!
mesh直腹杆
LATT,1,,1,,61,,2
LESIZE,ALL,1
LMESH,ALL
allsel
*get,xian1,line,,num,max
*get,dian3,kp,,num,max
k,dian3+1,0,11,-11
lsel,s,line,,xian1-6,xian1!
mesh上平直杆
LATT,1,,1,,dian3+1,,9
LESIZE,ALL,1
LMESH,ALL
*do,j,1,6
lsel,s,line,,166+2*j,167+2*j,1!
mesh上平斜杆
LATT,1,,1,,55+j,,10
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,178+2*j,179+2*j,1!
mesh上平斜杆
LATT,1,,1,,54+j,,10
LESIZE,ALL,1
LMESH,ALL
*enddo
*do,j,1,8
lsel,s,line,,134+2*j,135+2*j,1!
mesh下平斜杆
LATT,1,,1,,1+j,,10
LESIZE,ALL,1
LMESH,ALL
lsel,s,line,,150+2*j,151+2*j,1!
mesh下平斜杆
LATT,1,,1,,j,,10
LESIZE,ALL,1
LMESH,ALL
*enddo
3.2施加载荷、位移边界条件及求解
3.2.1定义位移约束
dk,1,ux,0,,0,uy,uz!
定义约束
dk,46,uy,0,,0,ux
dk,9,uy,0,,0,uz
dk,54,uy,0,,0
finish
3.2.2工况一恒载作用下桥梁结构分析(一恒+二恒)
/SOLU
acel,0,9.8,0!
自重
esel,s,sec,,13!
二恒
sfbeam,all,1,pres,-9800
allsel
solve
finish
3.2.2活载(全桥满布)作用下桥梁结构分析
/prep7
esel,s,sec,,13
sfbeam,all,1,pres,-46718.75
allsel
/SOLU
Solve
!
说明:
各荷载加载都是对于仅有位移约束,无荷载的结构上进行的,即荷载加载命令流并不连续。
3.2.3活载(全桥单线)作用下桥梁结构分析
/prep7
esel,s,elem,,1,128
sfbeam,all,1,pres,-46718.75
allsel
/SOLU
Solve
3.2.4活载(半桥同侧满布)作用下桥梁结构分析
/prep7
esel,s,elem,,1,32
esel,a,elem,,65,96
esel,a,elem,,129,160
esel,a,elem,,193,224
sfbeam,all,1,pres,-46718.75
allsel
/SOLU
Solve
3.2.5活载(半桥异侧满布)作用下桥梁结构分析
/prep7
allsel
esel,s,elem,,1,32
esel,a,elem,,65,96
esel,a,elem,,161,192
esel,a,elem,,225,256
sfbeam,all,1,pres,-46718.75
allsel
/SOLU
Solve
3.3求解结果(后处理)
3.3.1后处理命令
3.3.1.1结构整体挠曲图
Post1/
PLDISP,2
3.3.1.2主梁角点应力图
/post1
esel,s,se
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