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1、高级非线性分析技术及技巧(三)作者:冒小萍 审校:汪永财适用版本:NX所有版本接着高级非线性分析技术及技巧(二)介绍。迭代过程中过量的位移会导致扭曲变形的网格(如图1所示),引起的原因和解决方法如下:(1)如果该现象发生在第一个迭代步并且存在刚体运动、且设 置了 MSTAB=1 (使用刚度矩阵稳定性),那么有可能是MSFAC值设 太小了(矩阵稳定因子)。尝试提升缺省值到1E-9,如图2所示。SOLUTICh TINE = 0PlC000E-O2 50_261CkfiE*10EOUATIOH NO.=0.12971E+00WMl&i 2.=9505053774STEP HU1BER =1( TI
2、M: STEP = O.IOOOOE-CeHRXIHLM RB5 DIAG EUENEHi CF TbE FACTDEE.ZEI ffiTRIX = MINIMLH HI第 ELfl CF Th FACT她 ZED MflTSIK =OUT-OT-HORH OFCCHVERGBJCE RATIOSOXVEECDCE wias0UT*-yCE L啊沉 AHCEUT-OF-HALHMCENORM OF IttREKNIALFOR DUT-F-BALJ*EFOR IHCROEHTALVECTDfi DALUULflTimEhERGYFURZE NOPEHTEISPtROTH- CFORCEEFEHL
3、VFCRCEDISP.FORCEBETARfiTlDEQi(EQ HAX E0 跳0 芷口 欧0CAWnM&enROTH.CITE命牌VRLUE娜LUEVHJUEVALUEEFfftE WITHCOHFfifiE WITHeiolsixSOLPCTOL 0.45E-03S S妣*1050LLni0H TIrt: 0.10CxC-2IKITIAL EhO!Qf。.找仙孰*046依响OaOE*01 Q.OOEHJO o.occxoRESTART FCR ftnCMRTIC-TIf-$TEFPING AFTER ITERfiTIOH 2TIHE &TEFo.ioooocE-oeIntegration
4、 Order t-DirectionUse Incompatible Modes (ICMODE)Stiffness Matrix StabiIizatiMatnx Stabilization Factor (MSFAQDefaultle-010ContactRestartOtherTranslationIterative Solver ,*Equilibriuin SchemeLDC SchemeTLA SchemeAnalysis ControkAnalysis Options)Time IntegrationSOL 701 Time Stepping(HOT USZOXHOT LEH)(
5、2)时间步太大或者载荷不依赖于时间。需要降低时间步且/或 创建依赖时间的载荷。(3) 单元扭曲也会发生在靠后的时间步,此时模型一部分已经 由于材料屈服或进入塑性阶段开始软化。如果增量位移超出指定值, 可以用MAXDISP参数让程序自动调整回来,如图3所示。ContactRestartOtherTranslationIterative SolverEquilibriumATS SchemeLDC SchemeTILA SchemeAnalysis ControlAnalysis OptionsTime IntegrationSQL 701 Time SteppingIntegration Ord
6、er t-Direction (TINT) Use Incompatible Modes (ICMODE) Stiffness Matrix Stabilization (IV1STAB) Matrix Stabilization Factor (MSFAC) Element Death Time Delay (DTDELAY Shell DOF Angle (SDOFANG)Shell Drilling Stiffness Factor (DRILLKF) u/p Formulation (UPFORM)Large Strain Formulation (ULFORM)Prescribed
7、Displacements Option (DISPQPT)Pre理I mdu ripiticn .p nAncgQMaximum Displacement Limit (MAXDISP)Elastic Beam Formulation Algorithm (BEAMALG)0DefaultUsedle-0100sec T 5deg T 0.0001Not UsedULH/SOL 601 and UU/SOL 70 Original ConfigurationAffected by Structural Deforn 0mm Current如果看到变形单元信息开始于解算方案的中部,请查找过度增
8、量 位移。下面的案例是设置MAXDISP=30.0的数据,从11步(time=1.95) 开始(模型已经屈服后),增量载荷导致过度位移。有两次已经达到 最大设置增量位移,程序自动调整回来。ITE=73.53E+043.95E+06IB2 57-TL.76E+D62 .2EE+07 4555-X -B.B5E+D6B.53E+02 BB-Z| 5-D3E+DD |4.3 9E-0LB B - Z 5.0EE-6T2.03E+D36.26E+05L.60E-020.00E+000-00E+00O.ODE+ODD?OOEOO4.E4E-03L,ODE+OO(2)3.Z4E-01ITE=BB.1BE+
9、Oa1.63E+D6IB2 57-X -L.64E+051.D2E+0769 50 6-Y-L.15E+062.6TE+02 BB-Z | L .58E+DD |1.45E-DLBB-J 2.52E-02Z.BDE+036.2EE+053.3SE-030.00E+000-00E+000.0DE+00 D.DOEh-DO4.6LE-D31. 0DE+00(2)1.17E-0LITE=g6. 62E+023.04E+05IB2 57-X1.2BE+051.B2E+D6LB257-T7.B6E+D51L.L6E+02BBT6.32E-02BB-Z1.7 3E-02B.77E+026.2EE+052.
10、69E-04O.DOE+OOO.DOE+DO0.0DE+00O.ODE+DO1.40E-03L.OOE+OO(2)1.62E-0LITE=LOL.EBE+fll3.02E+0469 5 09-Z3.02E+03L.BTE+05 1579-T 3.75E+042.46E-D193 93 9-T| T -N7E-D3 |2.EEE-02BB-Z1.4 5E-0 23.B5E+026.29E+057.71E-060.00E+00 O.OOE+OO0.0DE+00O.OOE+Op6.25E-04L.OOE+OO(2)4 .24E-02ITE=113.61E+00L.e2E+03 7BB4-T -3.E
11、6E+02L.DSE+04 929B2-X4 .21E+032.6TE+00 449B3-Z F:L .63E-g 1.7BE-D3BB-Z -2.E9E-0 4L.EOE+OL6.2BE+051.47E-060.00E+000.00E+000.0DE+00O.ODE+OD2.E6E-05L.OOE+OO(2)1.40E-OLITE=122. E4E-D12.77E+02 7BBB-T 2.0EE+022 .EBE+03 924L0-X -1.70E+03L.74E-02 7B3B-Z6.5EE-D5 7B39-M -3 .55E-D5L.05E+0L6.2BE+051.16E-D70.00E
12、+000.00E+00O.ODE+OD dTooe+oo1.6BE-D5L.OOE+OO(11-9.B3E-D2ITE= 12L.OOE+OO3.64E-02L.E6E-O2L.E9E+0216E42-Z7.45E+01B.62E+02E454 9-X4 .63E+025.BOE-023.5LE-D44.49E-05L6E42-X -1.40E-D55.3TE-016.29E+051-4BE-0E牛表行以的是修衣酸薛于切力学0 0E+00O-ODE+OO D.OOE+OOq.OOE+OD(11B.54E-07ITE=L4l.L5E-0a2.LaE+01L996D-Y-L.45E+012 .3T
13、E+02924L0-X -L.4TE+023.23E-04-5 .bJ_E-U55.42E-0 6L9963-X2.B4E-064.37E-DL6.29E+054.6TE-1D0.00E+00 O.DOE+DO0.0DE+00Q.ODE+OD6.95E-071. ODE+OO(11-3.L5E-04ITE=I T EL5A2. 41E-D5A T I 0 H3.69E+0042 79-X -2.44E+00TIME3.25E+0L 4279-T2 .29E+0LLOG2.04E-03-L.23E-D51.62E-06L996D-T a.47E-D72.34E-026.29E+059.B1E-12O.DOE+OOO.DOE+DO0.0DE+00O.ODE+DOa.73E-0BL.OOE+OO(111.7JE-02图4更多内容请参考高级非线性分析技术及技巧(四)。