结构可靠度作业及答案

;,为对数正态分布;,为正态分布;,为极值I型分布。试用蒙特卡洛法计算该结构构件的可靠度。Р程序:Рclear;clc;РmuX=[2234.32;949.59;1521.9;496.1];РsigmaX =[0.1;0.1;0.109;0.292];РsLn1=sqrt(log(1+sigmaX(1)/muX(1)^2));РmLn1=log(muX(1))-sLn1*2/2;РsLn2=sqrt(log(1+sigmaX(2)/muX(2)^2));РmLn2=log(muX(2))-sLn2*2/2;РnS=1e6;?Рig=ones(nS,1);Рx1 = lognrnd(mLn1,sLn1,1,nS);Рx2 = lognrnd(mLn2,sLn2,1,nS);Рx3 = normrnd(muX(3),sigmaX(3),1,nS);Рsyms x alpha k; РEVIpdf = 'alpha*exp(-alpha*(x-k)-exp(-alpha*(x-k)))';РEVIcdf = 'exp(-exp(-alpha*(x-k)))';Рalpha=1.2825/sigmaX(4); Рk=muX(4)-0.5772/alpha; РEVIpdfStar = eval(vpa(subs(EVIpdf,x,muX(4)))); РEVIcdfStar = eval(vpa(subs(EVIcdf,x,muX(4)))); РaEv = normpdf(norminv(EVIcdfStar))/EVIpdfStar;РuEv = muX(4)-norminv(EVIcdfStar)*sigmaX(4);Рx4 = evrnd(uEv,aEv,1,nS);Рg=x1+x2-x3-x4; РnR=sum(ig(g>=0)); РPr=nR/nS Р结果:РPr=1