我做的是钢筋混凝土板的裂缝分析,中间的空心圆环表示为一根钢筋,通过对空间圆环施加温度载荷,模拟钢筋受到腐蚀后的膨胀,由于其膨胀,导致最终在钢筋表面产生裂缝.
下面是由在建模时所写的本分程序,
ALLSEL
Fini
/Clear
*DEL,ALL
/Filename,SlabCrk
/Title,CrkCorrSlab
!Definition of geometrical parameters
pi=3.1415926
d=12 !mm, Diameter, NO.19(19*0.125in)
r=0.5*d !mm, Radius
c=20 !mm,Thickness of Concrete Cover
ht=80 !mm
space=120 !mm
len_elm=4 !mm
area=len_elm*1 !mm2 !Affecting area for a single spring
corlayer=1 !mm
!Definition of material parameters
!Steel-bar
E_s=2e5 !N/mm2(MPa)
Nu_s=0.3 !Poisson ratio
Yield_s=335 !N/mm2(MPa)
!concrete
E_c=3.0e4/(1+2) !N/mm2(MPa), considering creep coef=2
Nu_c=0.2 !Poisson ratio
Uncomp_c=35 !N/mm2(MPa),
Unten_c=Uncomp_c/11 !N/mm2,
G_f=0.1 !N/mm2,G_f=100N/m
!Define Force-Deflection curve for Springs
w1=-0.1 !mm
f1=-Uncomp_c*area !N
w2=-1e-3
f2=-Uncomp_c*area
w3=0
f3=0
w4=1e-3
f4=Unten_c*area
W5=G_f/Unten_c
f5=0.3*Unten_c*area
w6=3.33*G_f/Unten_c
f6=1e-3*Unten_c*area
w7=20*3.33*G_f/Unten_c !2mm
f7=1e-3*Unten_c*area
!Definition of coefficients of expansion
co_exp=0.01
!Loading rate of temperature,T/year
T1=0
T2=0.5 !腐蚀发生后第一年温度荷载
/Prep7
!Concrete elements
et,1,42 !单元类型
KEYOPT,1,3,2
et,2,39 !单元类型
KEYOPT,2,3,0 !FOr vertical crk(disp along nodal x axes)
et,3,39 !单元类型
KEYOPT,3,3,2 !FOr horizontal crk(disp along nodal y axes)
R,1,w1,f1,w2,f2,w3,f3,w4,f4,
RMORE,w5,f5,w6,f6,w7,f7,
!Definiation of material behavior
!Concrete
mp,ex,1,E_c !砂浆材料线性参数,考虑徐变对弹模的影响,徐变系数取2
mp,prxy,1,Nu_c
!Steel-bar
!(1) Linear parameters
mp,ex,2,E_s
mp,prxy,2,nu_s
TREF,0
MPTEMP,1,T1,T2 !IN ACCENT ORDER
MPDATA,ALPX,2,1,0,co_exp ! SETTING THERMAL COEFFICIENT FOR RIGID BEAMS
MPDATA,ALPY,2,1,0,co_exp
MPDATA,ALPZ,2,1,0,co_exp
!--------------------------------------------------
!--------------------------------------------------
!生成实体模型
/device,vector,1
/pnum,area,1
BLC4,,,-(r+c),(r+c),
csys,4
CYL4,0,0,r,90,,180
asba,1,2
CYL4,0,0,r,90,r-corlayer,180
wpave,-(r+c),(r+c)
csys,0,
BLC4,,,r+c,ht-d-2*c
BLC4,,,-(0.5*space-c),ht-d-2*c
BLC4,,,-(0.5*space-c),-(r+c)
csys
WPCSYS,-1
wprota,45
wprota,,,90
asel,s,area,,1,3,2
asbw,all,,dele
allsel
csys
WPCSYS,-1,0
aglue,all
numcmp,all
nummrg,all
我只在钢筋表面处x轴及y轴建立弹簧单元combine39模拟水平及竖直裂缝,通过后处理分别得到x轴及y轴弹簧弹元的y方向及x方向的伸长信息,即为裂缝的宽度.
问题是在我列表显示y轴向弹簧单云伸长信息时,出现了两个弹簧单元伸长量为负值.
我估计是我在定义conmibe39实常数时可能出现了问题.我也查阅了相关文献,大多数文献中在建立钢筋混凝土模型,用combine39模拟钢筋与混凝土之间的粘结滑移时可根据Houde的粘结滑移公式定义其实常数.但与我讨论问题不想符合,请问该问题下我怎么定义实常数.还请群里的高手不吝赐教.
|