关于数值模拟的所有基础知识

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时间步是什么？

时间步长是指：比如说模拟10s，间隔时间段是0.1s，时间步是1,则0s对应的时间步为0，0.01对应的时间步为0.01s.

铁锤妹妹
请教edem默认的时间步是多少，如何能够保存指定时间步的h5文件
@铁锤妹妹

，像我这里的设置会生成20个h5文件，每个h5文件对应着保存间隔为0.05s保存的数据 ；另外时间步长一般取15%-25%，具体根据工况确定

收敛精度

ctrl+5





曲线

剪切弹性模量：$G=\frac{E}{2(1+\mu )}$
体积弹性模量：$K=\frac{E}{3(1-2\mu )}$

FLAC3D模拟的基础知识——添加显示，plot , axes, 等。
new
gen zone brick p0 0 0 0 p1 45 0 0 p2 0 1 0 p3 0 0 30 p4 45 1 0 p5 0 1 30 p6 45 0 30 p7 45 1 30 size 9 1 6
gen zone brick p0 45 0 0 p1 150 0 0 p2 45 1 0 p3 45 0 30 p4 150 1 0 p5 45 1 30 p6 150 0 30 p7 150 1 30 size 21 1 6 ratio 1.03 1 1
gen zone brick p0 45 0 30 p1 150 0 30 p2 45 1 30 p3 75 0 60 p4 150 1 30 p5 75 1 60 p6 150 0 60 p7 150 1 60 size 21 1 6 ratio 1.03 1 1
;attach face range x=44.9 45.1
;attach face range z=29.9 30.1
;′′?¨D?μ?êóí?2￠??ê?í???
;plot block group
plot create plot Trench-1
;plot add surface yellow
plot add axes
plot show
;================================================================
;éè??±???ì??t
fix x y z range z -0.1 0.1
fix x y range x -0.1 0.1
fix x y range x 149.9 150.1
fix y range y -0.1 0.1
fix y range y 0.9 1.1
;=================================================================
;?¨ò?2?á?2?êy
model mohr
property bulk=2.0e8 shear=1.0e8 coh=1e5 fric=35 tens=1e5
;=================================================================
;3?ê?ó|á|μ?éú3é
set gravity 0,0,-9.81
ini dens 2500
ini xdis=0 ydis=0 zdis=0
;=================================================================
history n=5
history unbal
history gp zdisp 45,0,30
history gp zvel 45,0,30
set mech force=100
solve
plot hist 1
plot hist 2
plot hist 3
;===========================================
;??ò?μè?μ??í? !
plot create plot Trench-2
plot add contour zdisp
plot add axes
plot show
;===========================================
;ó|á|μè?μ??í?
plot create plot Trench-3
plot add bcontour szz
plot add axes
plot show
;===========================================
;è?ò??ê??é?μ?μè?μ??í?
plot create plot GravV
;plot set plane origin=45,1,30 normal 1 1 1
plo set pla ori 1.5 1.5 1.5 norm 1 1 1
plot set rot 15 0 20
plot set center 75 25 30
plot add bound behind
plot add bcontour szz plane
plot add axes
plot show
;============================================
;?ù?èê?á?í?
plot create plot Trench-4
plot add grid vel red
plot add axes
plot show
show Trench-1
show Trench-2
show Trench-3
show Trench-4
;============================================
;?ó?a°2è??μêy
;×??¨ò???è???·¨
def SSR
;=====================================================
;?¨ò?óD1?2?êyò??°?-?·???1ì??t
ait1=0.02
k11=1.0
k12=2.5
ks=(k11+k12)/2
loop while (k12-k11)>ait1
coh1=1e5
fri1=(atan((tan(20*pi/180))/ks))*180/pi
dila1=35
ten1=1e5
grav0=-9.81
dens1=2500
K1=2.0e8
G1=1.0e8
;=====================================================
;???μ?êμ??1y3ì
command
model null
model elastic
pro bulk=2.0e8 shear=1.0e8 coh=1e5 fric=35 tens=1e5
fix x y z range z -0.1 0.1
fix x y range x -0.1 0.1
fix x y range x 149.9 150.1
fix y range y -0.1 0.1
fix y range y 0.9 1.1
set grav 0 0 grav0
solve step=10000
ini xdisp 0 ydisp 0 zdisp 0
ini xvel 0 yvel 0 zvel 0
model mohr
pro bulk=2.0e8 shear=1.0e8 coh=1e5 fric=35 tens=1e5
set mech ratio 9.8
solve step 30000
endcommand
;=====================================================
;?t·?·¨μ?êμ??1y3ì
if mech_ratio<1.0e-5
k11=ks
k12=k12
else
k12=ks
k11=k11
endif
ks=(k11+k12)/2
endloop
;=====================================================
;???á1?μ?±￡′?
fosfile0=‘fos’+’.sav’
command
save fosfile0
endcommand
end
;=====================================================
;3ìDò?′DD?°?á1???ê?
@SSR
pr ks

记录数据

hist add unbal
hist add gp xvel 3 4 4
hist add gp zdisp 0 0 8
;step 1500
solve
plot hist 1

显示边界条件

六个面，只有顶面没有被约束 怎么看约束呢？ 只需要点击list-zone-gp fixity即可 显示这个云图的命令是 plot add gpfix（只有约束，没有实体单元） 

施加波荷载，动态分析

边坡稳定性分析
2. Verification of FEM code for unreinforced slopes
2.1. General
With the exception of modifications for reinforced slopes, the
open-source FEM code (mrslope2d) described by Fenton and Griffiths [15] and available at ‘‘http://courses.engmath.dal.ca/rfem/”
was used in the current study. The deterministic slope stability
analysis part of the code (Program 6.4, [37] is based on the shear
strength reduction method. This program is for two-dimensional
slope stability analysis of unreinforced slopes with elasticperfectly plastic soils governed by the Mohr–Coulomb failure criterion. Eight-node quadrilateral elements are used. The bottom of the
slope foundation is fixed in both horizontal and vertical directions.
The vertical boundaries on both sides are fixed in the horizontal
direction. The gravity ‘‘turn-on method” is used in Program 6.4
(see [20])

The SVSlope software package [16] was used to carry out circular slip analyses (Bishop’s Simplified Method) together with the Floating Method option for probabilistic analyses.

2.1. General
With the exception of modifications for reinforced slopes, the
open-source FEM code (mrslope2d) described by Fenton and Griffiths [15] and available at ‘‘http://courses.engmath.dal.ca/rfem/”
was used in the current study.

FLAC3D地震分析

https://www.docin.com/p-433144744.html#:~:text=%E9%87%87%E7%94%A8flac3d,%E7%BA%A62.0m%2Fs%E3%80%82

北伊 2015-04-14 08:23

wanglunan 2015-04-15 11:28
北伊:那样就像你说的，太扯淡了。
应该是按照“solve age” 中的时间确定，而不是时步。时步与时间的关系不一定乘个系数就可以的，有的时候时步是变化的。 (2015-04-14 08:23)

solve age=t的意思是进行t个时间单位的动力计算，一般单位是s。这个解释对吗？

请问如果是静力问题是否可以用 solve age=t确定模拟时间？

FLAC3D动力分析，管道地震探测

 new title config dyn gen zon radcyl p0 0 0 4.5 p1 7.5 0 4.5 p2 0 0.1 4.5 p3 0 0 10 dim 2.5 2.5 2.5 2.5 ratio 1 1 1 1 size 10 1 16 20 group weiyan fill group kaiwa gen zon brick p0 0 0 3 p1 2.5 0 3 p2 0 0.1 3 p3 0 0 4.5 ratio 1 1 1 size 10 1 5 group kaiwa gen zon brick p0 2.5 0 3 p1 7.5 0 3 p2 2.5 0.1 3 p3 2.5 0 4.5 ratio 1 1 1 size 20 1 5 group bang gen zon brick p0 0 0 0 p1 7.5 0 0 p2 0 0.1 0 p3 0 0 3 ratio 1 1 1 size 30 1 9 group dibian plot block gro gen zone reflect normal -1 0 0 origin 0 0 0 ;模型 model elas prop shear 1e9 bulk 2e9 ini dens 2500 def cjl if dytime<=1e-3 cjl=1000*dytime else if dytime<=2e-3 cjl=-1000*dytime+2 else cjl=0 endif endif end ;设置初始应力边界条件 ;set grav 0 0 -10 fix x range x -7.49 -7.51 fix x range x 7.49 7.51 fix y fix z range z -0.1 0.1 apply nquiet range z=10 apply squiet range z=10 apply szz -1e5 hist cjl range z=10 x -1 1 hist gp zvel 0,0,10 set dyn time=0 hist dytime hist cjl set dyn dt 5e-7 set dyn damp local 0.15 ;局部阻尼 plot add hist -1 vs 2 plot show solve age 3e-2 

地震波数据下载
http://okok.org/redirect.php?tid=12824&goto=nextoldset

因此在对静水条件下的海底斜坡进行建模时，
－２４－

大连理工大学博士学位论文–朱斌



可以忽略水深的影响而以有效重度赋值土体进行计算。

 获取主应力 ```bash def getsig p_z=find_zone(18) s1=z_sig1(p_z) s2=z_sig2(p_z) s3=z_sig3(p_z) end getsig 

FLAC3D进行Table运算

new table 1 read '18s_acc.txt' plot create view table_calc_show def table_calc(int_in) inp = get_table(int_in) nitem = table_size(inp) loop nn(1,nitem) ii=out(nn) xtable(2,nn)=xtable(1,nn) ytable(2,nn)=ytable(1,nn)*10 endloop end @table_calc(1) plot add table 1 2 

FLAC3D 5.0查看有效应力

plot zcon szz effective

FLAC3D中保存屏幕输出的一种方法——写到文件中

set log on
set logfile ‘baocun.txt’
print @ks
set log off

记录输出的内容到文件中

海床地震动力响应

海床液化FLAC3D7.0
文章：Study on the influence of the seafloor soft soil layer on seismic ground motion Jingyan Lan