ANSYS中PLANE183模型在自重作用不收斂問(wèn)題解決

2017-04-24 by:CAE仿真在線來(lái)源:互聯(lián)網(wǎng)

1、問(wèn)題描述

簡(jiǎn)單的2D軸對(duì)稱土層,寬度為4000mm,深度為19700mm。簡(jiǎn)單約束條件。單元類型為PLANE183,泊松比為0.49。當(dāng)KEYOPTION為默認(rèn)值,該模型在自重作用下無(wú)法計(jì)算收斂。命令流詳見(jiàn)附件。

ANSYS中PLANE183模型在自重作用不收斂問(wèn)題解決ansys workbanch圖片1

2、幾種可能的解決方法

1)泊松比為0.49造成的?

0.49接近為不可壓縮材料,將其改為0.3后,仍然無(wú)法收斂;

2)單位劃分方式造成的?

模型原始單元?jiǎng)澐址绞綖樽杂傻娜切?后改為規(guī)則的矩形單位,仍然無(wú)法收斂;

3)將PLANE183的KEYOPTION(6)由0改為1,即可成功收斂。

ANSYS中PLANE183模型在自重作用不收斂問(wèn)題解決ansys workbanch圖片2

3、相關(guān)參考資料

ANSYS中PLANE183模型在自重作用不收斂問(wèn)題解決ansys圖片3

2關(guān)于DP材料的一個(gè)簡(jiǎn)單例子,計(jì)算不收斂的原因探討

問(wèn)題描述:一個(gè)正方形,左右兩邊及下邊界約束住相應(yīng)方向的位移,上邊界施加9e8pa的均布荷載,進(jìn)行求解。
只是為了學(xué)習(xí)DP準(zhǔn)則,所以材料參數(shù)沒(méi)有實(shí)際參照。
為什么總是不收斂?請(qǐng)高手指教!!!不勝感激!!

問(wèn)題基本解決,經(jīng)驗(yàn)證不是DP材料的問(wèn)題,主要原因在于單元問(wèn)題

3)PLANE183 DP本構(gòu) 接觸分析

[Details]
1) Keypoints
(0,0)-(100,0)-(100,20)-(100,50)-(100,60)-(45,50)-(0,50)-(0,60)

2) Plane183 element; D-P material
? Area1:
ü E(Young's modulus)=20e9
ü v(Poisson's ratio)=0.20
ü ρ=2000
ü γ(dilatancy angle)=18
ü θ(frictional angle)=36
ü C(cohension)=10e6
? Area2 and Area3:
ü E(Young's modulus)=30e9
ü v(Poisson's ratio)=0.25
ü ρ=2500
ü γ(dilatancy angle)=22
ü θ(frictional angle)=44
ü C(cohension)=20e6
3) Contacts
? Red line is for fault contact,frictional coefficient=0.3
? Green line is for interval contact,frictional coefficient=0.6
? Use no separation behavior of contact surface
? Normal penalty stiffness=0.1
? Others are using the defaults
4) Solution settings
? Open large displacement
? Use automatic time stepping
? Time at end of loadstep=10
? Time step size=1
? Min=0.1
? Max=10

命令流附件:

/PREP7
!---------element types & settings-----------
et,1,183 ! for soil
KEYOPT,1,1,0
KEYOPT,1,3,1
KEYOPT,1,6,1

!******************material properties*****************
MPTEMP,,,,,,,,
MPTEMP,1,0
MP,EX,1,10.4 !soil =500su,su取9920范圍內(nèi)的平均值(16+25.424)/2=20.7kpa。
MP,NUXY,1,0.49 !poisson's ratio
MPDATA,DENS,1,,1.6e-9

TB,DP,1,,,
TBMODIF,1,1,0.012
TBMODIF,1,2,13.1
TBMODIF,1,3,13.1

!TB,BISO,1,1 !bilinear isotropic material
!TBDATA,1,0.016 !yield stress in MPa,取自王棟的論文
!TBDATA,2,0.95

!------------geometry creation-------------------
RECTNG,0,4000,0,-19700, ! SOIL
CM,SOIL,AREA
!-------------soil meshing----------------
type,1
mat,1
real,1

CMSEL,S,SOIL
LSLA,S
LESIZE,ALL,200, , , , , , ,1

MSHAPE,0,2D
MSHKEY,1

AMESH,SOIL !變模型時(shí)參數(shù)需修改

!-----boundary conditions & loading-------
/SOL
LSEL,S,LOC,X,0
DL,ALL, ,SYMM !施加對(duì)稱約束
alls

LSEL,S,LOC,Y,-19700
DL,ALL,,UY !施加土底UY約束
alls

CMSEL,S,SOIL
LSLA,S
LSEL,R,LOC,X,3900,4100
DL,ALL,,UX !施加土邊界UX約束
alls

!--------------initial stress-------
/SOLU
TIME,1
ACEL,0,9800,0,

solve

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