Re: need your help
- To: mathgroup at smc.vnet.net
- Subject: [mg118361] Re: need your help
- From: Arezoo Sadrinezhad <as144 at zips.uakron.edu>
- Date: Sun, 24 Apr 2011 08:25:57 -0400 (EDT)
- References: <BANLkTinHsewBB465Pns344Y3sBLOf9DNnQ@mail.gmail.com>
Hello Mathematica Friends, I am stuck with this problem, where I use NDSolve[] to solve a partial differential equation. The error is: NDSolve::ndnum: Encountered non-numerical value for a derivative at t==0! The sample code is below. Please suggest me ways to solve this problem. Thank you. -- Best regards, Arezoo Sadrinezhad Ph.D. Student Department of Civil Engineering University of Akron Akron, Ohio 44325-3905 Email: as144 at zips.uakron.edu <mailto:as144 at zips.uakron.edu> This is my code: AC11=10; AC22=5; DC1111=25; DC2222=6.25; LB=-0.06; RB=0.1; StressIC[s11_,s22_]:=Limit[(1/((2Pi)*c*c))*Exp[-(1/2)*(((s11-0)/c)^2+((s22-0)/c)^2)],c->0.001]; Plot3D[StressIC[s11,s22],{s11,-0.1,0.1},{s22,-0.1,0.1},AxesLabel->{"sigma11","sigma22","P[s11,s22,0]"}] YieldStressDistribution=NormalDistribution[0.05,0.5*0.05]; CDF[YieldStressDistribution,h] Plot[CDF[YieldStressDistribution,h],{h,-0.2,0.2}] YF[s11_,s22_]=Abs[s11-s22]; cumuldist[s11_,s22_]=0.5*(1+Erf[28.2843*(-0.05+YF[s11,s22])]) Plot3D[cumuldist[s11,s22],{s11,-0.4,0.4},{s22,-0.25,0.25},PlotRange->All] AC11p[s11_,s22_]=AC11*(1-cumuldist[s11,s22]) AC22p[s11_,s22_]=AC22*(1-cumuldist[s11,s22]) DC1111p[s11_,s22_]=DC1111*(1-cumuldist[s11,s22]) DC2222p[s11_,s22_]=DC2222*(1-cumuldist[s11,s22]) ElasticPlasticEq={D[AC11p[s11,s22]*P[s11,s22,t],s11]+2*D[AC22p[s11,s22]*P[s11,s22,t],s22]+D[P[s11,s22,t],t]-D[DC1111p[s11,s22]*P[s11,s22,t]*t,{s11,2}]-2*D[DC2222p[s11,s22]*P[s11,s22,t]*t,{s22,2}]==0,P[s11,s22,0]==StressIC[s11,s22], AC11p[LB,s22]*P[LB,s22,t]-(D[DC1111p[s11,s22]*P[s11,s22,t]*t,s11]/. s11->LB)==0, AC11p[RB,s22]*P[RB,s22,t]-(D[DC1111p[s11,s22]*P[s11,s22,t]*t,s11]/. s11->RB)==0, 2*AC22p[s11,LB]*P[s11,LB,t]-2*(D[DC2222p[s11,s22]*P[s11,s22,t]*t,s22]/. s22->LB)==0, 2*AC22p[s11,RB]*P[s11,RB,t]-2*(D[DC2222p[s11,s22]*P[s11,s22,t]*t,s22]/. s22->RB)==0} Off[General::stop]; t=.; ElasticPlasticSol=NDSolve[ElasticPlasticEq,P[s11,s22,t],{s11,LB,RB},{s22,LB,RB},{t,0,0.03}, StepMonitor:>Print[t],SolveDelayed->True] I would be really grateful if you could help me! I really get stuck. > > On 04/23/11 18:01, Arezoo Sadrinezhad wrote: > >> Hello Mathematica Friends, >> >> I am stuck with this problem, where I use NDSolve[] to solve a partial >> differential equation. >> >> The error is: NDSolve::ndnum: Encountered non-numerical value for a >> derivative at t==0! >> >> The sample code is attached to this email. >> >> Please suggest me ways to solve this problem. Thank >> you. >> >> >> -- >> Best regards, >> >> Arezoo Sadrinezhad >> Ph.D. Student >> Department of Civil Engineering >> University of Akron >> Akron, Ohio 44325-3905 >> Email: as144 at zips.uakron.edu <mailto:as144 at zips.uakron.edu> >> > -- Best regards, Arezoo Sadrinezhad Ph.D. Student Department of Civil Engineering University of Akron Akron, Ohio 44325-3905 Email: as144 at zips.uakron.edu