在侧水压与顶部集中力作用下的柱子的地震反应谱分析,谱值为加速度反应谱,考虑X与Y向地震效应作用。已知地震影响系数a与周期T的关系: a(T)= 0.4853*(0.4444+2.2222*T) 0<T<=0.04 秒 0.4853*(0.10/T)^(-0.686) 0.04<T<=0.1 秒 0.4853 0.1<T<=1.2 秒 0.4853*(1.2/T)^1.5 1.2<T<=4 秒
以下是命令流程序
----------------------------------------------------------------------------------------------------
/filname,SPEC,1
/PREP7
!定义单元类型及材料特性 ET,1,45
MP,EX,1,2.8E10 MP,DENS,1,2.4E3 MP,NUXY,1,0.18
!建立模型 BLOCK,0,1,0,1,0,5
!网格剖分 ESIZE,0.5 VMESH,all
/VIEW,,-0.3,-1,1 EPLOT
FINISH
/SOLU
!施加底部约束 ASEL,,LOC,Z,0 DA,ALL,ALL ALLSEL
!施加自重荷载 ACEL,0,0,10
!进行模态求解
ANTYPE,MODAL MODOPT,LANB,30
SOLVE FINISH
!进行谱分析 /SOLU
ANTYPE,SPECTR
SPOPT,SPRS,30,YES
SVTYP,2 !加速度反应谱 SED,1,1 !X与Y向
FREQ,0.2500,0.2632,0.2778,0.2941,0.3125,0.3333,0.3571,0.3846,0.4167 FREQ,0.45,0.5000,0.5556,0.6250,0.7143,0.8333,1.1111,2.0000,10.0000 FREQ,25.0000,1000.0000
SV,0.05,0.0797,0.0861,0.0934,0.1018,0.1114,0.1228,0.1362,0.1522,0.1716 SV,0.05,0.1955,0.2255,0.22,0.3152,0.3851,0.4853,0.4853,0.4853,0.4853 SV,0.05,0.2588,0.2167
SOLVE
FINISH
!进行模态求解(模态扩展) /SOLU
ANTYPE,MODAL EXPASS,ON
MXPAND,30,,,YES,0.005 SOLVE FINISH
!进行谱分析(合并模态) /SOLU
ANTYPE,SPECTR SRSS,0.15,disp SOLVE FINISH
/POST1
SET,LIST !结果1 /INP,,mcom lcwrite,11
LCASE,11
PRRSOL, !结果2 SET,FIRST
PRRSOL, !结果3 SET,NEXT
PRRSOL, !结果4 SET,NEXT
PRRSOL, !结果5 SET,NEXT
PRRSOL, !结果6 FINISH
!静力分析
/SOLU
ANTYPE,STATIC
!施加水压荷载 NSEL,,LOC,Y,0 NSEL,R,LOC,Z,0,5
SFGRAD,PRES,0,Z,0,-10000 SF,ALL,PRES,50000
!施加集中荷载 NSEL,,LOC,Y,0 NSEL,R,LOC,z,5 F,ALL,FY,10000
ALLSEL EPLOT SOLVE FINISH /POST1 set,last lcwrite,12 Lcase,11
Lcoper,add,12 Lcwrite,13
LCASE,12
PRRSOL, !结果7 LCASE,13
PRRSOL, !结果8
FINISH
---------------------------------------------------------------------------------------------------
以下是计算的结果
--------------------------------------------------------------------------------------------------- 结果1:(Results Summary) 1 21.7 2 21.7 3 121.51
4 121.51
结果2:(单独谱分析反力LCASE,11) VALUE 2467.9 2290.1 18384.
结果3:(单独谱分析反力SET,FIRST)
VALUE 0.13334E+06-0.15785E+07-0.18819E-06
结果4:(单独谱分析反力SET,NEXT)
VALUE -0.15785E+07-0.13334E+06-0.418E-06
结果5:(单独谱分析反力SET,NEXT) VALUE -0.87805E+07 0.27008E+08 0.86846E-07
结果6:(单独谱分析反力SET,NEXT)
VALUE 0.27008E+08 0.87805E+07 0.79325E-06
结果7:(单独静力分析反力LCASE,12) VALUE 0.22901E-08-0.15500E+06 0.12000E+06
结果8:(谱分析与静力分析叠加反力LCASE,13) VALUE 2467.9 -0.15271E+06 0.13838E+06
---------------------------------------------------------------------------------------------------
以下是问题的讨论
---------------------------------------------------------------------------------------------------
1、模态提取数为30,即取前30阶振型数,但在谱分析时得到的是4阶,这4阶是什么意思?
2、在单独谱分析时,为何结果2、3、4、5、6会相差如此之大?(其应力和位移也是如此。) 3、在进行谱分析的合并模态步骤中,模态合并方法应该选用SRSS,0.15,DISP还是SRSS,0.15,ACEL(其对结果影响很大)?
4、在谱分析中,似乎应该将水压力折算成各节点处的附加质量MASS21,但对于非竖值方向(如本例为Y方向),MASS21单元如何加上去?
5、在选取(离散)频率和谱值时,似乎没有一定的标准,而其基本原则是须选取具有代表性的点。
6、模态分析中采用Subspace法与Block Lanczos法所得结果相差2%~4%左右,用后一种方法计算更快,但占用内存大50%左右。
7、在网格剖分时采用VMESH和VSWEEP两种方法,对静力分析结果没有影响,但对谱分析结果却有一定影响,何也? 8、有朋友说可以“做模态分析之前先做打开预应力的静力分析,然后再做打开预应力的模态分析,接着和以前一样”,但我试了试,得到的结果相差很大,不知何故,如果哪位朋友曾经作过这方面的例子,能否再试一下本例,以便进行比较!
因篇幅问题不能全部显示,请点此查看更多更全内容
Copyright © 2019- huatuo0.com 版权所有 湘ICP备2023021991号-1
违法及侵权请联系:TEL:199 1889 7713 E-MAIL:2724546146@qq.com
本站由北京市万商天勤律师事务所王兴未律师提供法律服务