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1、结构可疝度分析与设计的编程实践摘要:结构可靠性设计方法的开展经历了多个阶段,20世纪40年代开展起来的可靠性方法是结构可靠性设计方法的一个里程碑。本文简要介绍了结构可靠度分析与设计的根本原理,并通过MATLAB语言进行编程实现了改良一次二阶矩方法、R-F方法、可靠度校准分析等,并给出了例题的结果。1.引言结构可靠性设计方法的开展经历了多个阶段,20世纪40年代开展起来的可靠性方法是结构可靠性设计方法的一个里程碑,可靠性方法用可靠度或可靠指标描述工程结构的平安性,目前己形成了一套完整的理论并在设计标准中得到应用。可靠性方法是传统设计方法的延伸,其目标是将工程结构的可靠性用设计变量的概率特征来反映
2、,这样设计得到的是一个具有明确概率值的结果。尽管由于问题的复杂性,目前这一概率值仍不能与结构或结构构件的真实失效概率等同起来,但在描述工程结构可靠性方面毕竟有了一个可定量和比照的尺度。从简单到复杂或精确程度的不同,先后提出的可靠度计算方法有一次二阶矩法、二次二阶矩法,蒙特卡洛法以及其他方法。一次二阶矩法又分为中心点法和验算点法,其中,验算点法是目前可靠度分析最常用的方法。2.结构可靠度分析的根本原理结构可靠度即使结构在规定的时间内和规定的条件下完成预定功能的概率称之为结构的可靠度。结构的可靠度是结构可靠性的度量。通常用结构可靠度指标户或者结构失效概率来表示。结构在规定的时间,在规定的条件,完成
3、预定功能的概率称为结构的可靠度。结构可靠度是结构可靠性的概率度量,它与结构失效概率之间的关系为号=(-/?)假设功能函数Z=g(X,XzX”),X,是与结构可靠度计算有关的随机变量,Z是随机变量,假定其概率密度函数为/;(Z),那么结构的平安概率为p,=p(z0)=L/z(z/z,结构的失效概率为P/=p(zW0)=J,力(z)dz。假设抗力的PDF和CDF为:人(力,外(),作用的PDF和CDF为:八,E(三)。那么ps=p(z0)=fR(r)fs(s)drds,0pf=p(z0)=fr)fs(s)drds。其中失效概率可分别表示为:z0或者表示为:pf=P(Z0)=fr)fss)drds=
4、JJs(s)O表示结构的可靠状态,Z0.0001n=n+l;beta(n)=-12895/(3000*alphal(n-l)+4000*alpha2(n-l)+75O*beta(nl)*alphal(n-l)*alpha2(n-l)-124.2*beta(n-l)*alpha3(nl)alphal(n)=-(3000+750*beta(nl)*alpha2(nl)sqrt(3OOO+75O*beta(nl)*alpha2(11-1)2+(4000+750*beta(n-l)*alphal(n-l)2+(-124.2)2)alpha2(n)=-(4000+750*beta(nl)*alphal(
5、nl)sqrt(3000+750*beta(11-l)*alpha2(11-1)2+(4000+750*beta(n-l)*alphal(n-l)2+(-124.2)2)alpha3(n)=124.2/sqrt(3000+750*beta(nl)*alpha2(nl)2+(4000+750*beta(nl)*alphal(n-l)2+(-124.2)2)endfori=3:1:nbeta;alphal(1);alpha2;alpha3(i);endP1425.3clearclcFr=2500;P=10000;miu.x=2500,10000;sigma_x=miu_x.*0.3,O.13;xl
6、三Fr,P;delta_l=l;%开始循环,直至误差到达允许范围,允许误差设为0.OOlepsiIong=O.OOl;i=0;whiledelta_lepsilongi=il;:X(l,D=Xl(I);X(2,i)=xl(2);x=x1;g=121.2*x(l)-3.25*x(2);dg=121.2,-3.25;beta_l=(g+sum(dg.*(miu-)/sqrt(sum(dg.*sigma_x).2);X(3,i)=beta.l;alpha_x=dg.*sigma_x/sqrt(sum(dg.*sigma_x).2);x1-miu_x+beta_l*sigma_x.*a1pha_x;d
7、elta_l=sqrt(sum(xlx).2);end%循环完成,输出最后一次循环计算出的可靠指标和误差fprintf(二4fn,beta_l)fprintf(=%.8fn,delta_l)附件2:Homework2.2例3.5%RF2_2%g=R-G-Qmu_G=50;mu_Q-85;mu_R=250;Sigma_G=2.5;sigma_Q=17;sigma_R=25;Gstar_e=mu_G;Rstar_e=mu_R;Qstar_e=mu_Q;Qstar=O;Rstar=O;Gstar=O;i=0;whileabs(EGstar,Qstar,Rstar-Gstar_e,Qstar_e,Rs
8、tar_e)=le-3le-3le3Gstar=Gstar_e;Qstar=Qstar_e;Rstar=Rstar_e;mu_lnR=log(mu_R/sqrt(1+(sigma_R/mu_R)2);mu_R_e=Rstar*(l-log(Rstar)+mu_lnR);sigma_1nR=sqrt(log(l+(sigma_R/mu_R)2);sigma_R_e=Rstar*sigma_lnR;alpha=pi/(sqrt(6)*sigma_Q);u=mu_Q0.5772/alpha;F_Q=exp(-exp(-alpha*(Qstar-u);f_Q=alpha*exp(-alpha*(Qst
9、ar-u)-exp(-alpha*(QStaru);Sigma_Q_e=normpdf(norminv(F_Q)/f_Q;mu_Q_e=Qstar-norminv(F_Q)*sigma_Q_e;mu_G_e=mu_G;Sigma_G_e=sigma_G;%正态化后极限状态方程变为g=R_e-G_e-Q_ebeta=(Rstar-Gstar-Qstar+(mu_R_eRstar)-(mu_G_eGstar)-(mu_Q_c_Qstar)sqrt(sigma_R_e2+sigma_G_e2+sigma_Q_e2);a1pha_R_e=_sigma_R_e/sqrt(sigma_R_e2+sigma
10、_G_e2+sigma_Q_e2);a1pha_G_e=sigma_G_e/sqrt(sigma_R_e2+sigma_G_e2+sigma_Q_e2);a1pha_Q_e=sigma_Q_e/sqrt(sigma_R_e2+sigma_G_e2+sigma_Q_e2);Rstar_e=mu_R_e+a1pha_R_e*sigma_R_c*beta;Qstar_e=mu_Q_e+alpha_Q_e*sigma_Q_e*beta;Gstar_e-mu_G_e+alpha_G_e*sigma_G_e*beta;endbetaRstarGstarQstarP1235.9clearall;u_r=20
11、0;d_r=20;u_q=100;d_q=12;u_lnr=log(200/sqrt(1+0.12);d_lnr=sqrt(log(l0.12);r_star=u_r;q_star=u_q;ur_star=r_star*(llog(r_star)+u_lnr);dr_star=d_lnr*r_star;t=exp(0.1068*(qstar94.5955);f_qstar-0.1068*exp(-0.1068*(qstar94.5955)t);Fq_star=exp(t);nq=norminv(Fq_star);dq_star=normpdf(nq)/f_qstar;uq_star=q_sta
12、r-nq*dq_star;bate_l=(ur_staruq_star)/sqrt(dr_star2+dq_star2);cosr_star=-dr_star/sqrt(dr_star2+dq_star2);cosq_star=dq_star/sqrt(dr_star2+dq_star2);r_star=ur_star+cosr_star*bate_l*dr_star;q_star=uq_star+cosq_star*bate_l*dq_star;ur_star=r_star*(l-log(r_star)+u_lnr);dr_star=d_lnr*r_star;t=exp(-0.1068*(q
13、_star-94.5955);f_qstar=0.1068*exp(-0.1068*(q_star94.5955)t);Fq_star=exp(-t);nq=norminv(Fq_star);dq_star=normpdf(nq)/f_qstar;uq_star=q_starnq*dq_star;bate_2=(ur_staruq_star)/sqrt(dr_star2+dq_star2);whileabs(bate_2-bate_l)le4bate_l=bate_2;cosr_star=_dr_star/sqrt(dr_star2+dq_star2);cosq_star=dq_star/sq
14、rt(dr_star2+dq_star2);r_star=ur_star+cosr_star*bate_l*dr_starq_star=uq_star+cosq_star*bate_l*dq_starur_star=r_star*(l-log(r_star)+u_lnr);dr_star=d_lnr*r_star;t=exp(0.1068*(q_star94.5955);f_qstar=0.1068*exp(0.1068*(q_star94.5955)-t);Fq_star=exp(-t);nq=norminv(Fq_star);dq_star=normpdf(nq)/f_qstaruq_st
15、ar=q_star-nq*dq_starbate_2=(ur_staruq_star)/sqrt(dr_star2+dq_star2)endpf=normcdf(bate_2)P1255.10%RF2222%g=R-Qmu_R-input(muR=);deta_R二input(detaR=);mu_Q-input(,muQ:);deta_Q-input(detaQ二);sigma_R=mu_R*deta_R;Sigma_Q=mu_Q*deta_Q;Rstar_e-mu_R;Qstar_e-mu_Q;Qstar-O;Rstar=O;whileabs(Qstar,Rstar-Qstar_e,Rst
16、ar_e)=0.0001,0.0001Qstar=Qstar_e;Rstar=Rstar_e;mu_lnR=log(mu_R/sqrt(l+(sigma_R/mu_R)2);mu_R_e=Rstar*(llog(Rstar)+mu_lnR);sigma_1nR-sqrt(log(l+(sigma_R/mu_R)2);sigma_R_e=Rstar*sigma_lnR;muQ-ezzmu-Q;Sigma_Q_e=sigma_Q;beta-(Rstar-Qstar+(mu_R_e-Rstar)-(mu_Q_e_Qstar)sqrt(sigma_R_e2+sigma_Q_e2);alpha_R_e=
17、-sigma_R_e/sqrt(sigma_R_e2+sigma_Q_e2+sigma_Q_e2);a1pha_Q_e=sigma_Q_e/sqrt(sigma_R_e2+sigma_Q_e2+sigma_Q_e2);Rstar_e=mu_R_e+alpha_R_e*sigma_R_e*beta;Qstar_e=mu_Q_e+a1pha_Q_e*sigma_Q_e*beta;endbetaRstarQstar输入:mu_R=150deta_R=0.02mu_Q=120deta_Q=00.07P1275.11clearall;uf=40;v_f=0.1;u_z=100;v_z=0.04;u_m=
18、2000;v_m=0.1;d_f=u_f*v_f;d_z=u_z*v_z;d_m=u_m*v_m;u_lnf=log(40/Sqrt(I+0.12);d_lnf=sqrt(log(l+0.12);f_star=u_f;z_star=u_z;m_star=u_m;uf_star=f_star*(llog(f_star)+u_lnf);df_star=d_lnf*f_star;t=exp(-6.4e3*(m_star1909.8);f_mstar=6.4e3*exp(-6.4e3*(m_star-1909.8)t);Fm_star=exp(-t);nq=norminv(Fm_star);dm_st
19、ar=normpdf(nq)/f_mstar;um_star=m_star-nq*dm_star;D-sqrt(f_star*d_z)2+(z_star*df_star)2+(dm_star)2);bate_l=(f_star*u_z+z_star*uf_star-f_star*z_star-um_star)/Dcos_f=z_star*df_star/D;cos_z=-f_star*d_z/D;cos_m-dm_star/D;f_star-uf_star+cos_f*bate_l*df_star;z_star=u_z+cos_z*bate_l*d_z;m_star-um_star+cos_m
20、*bate_l*dm_star;uf_star-f_star*(llog(f_star)+u_lnf);df_star=d_lnf*f_star;t=exp(6.4e3*(m_star-1909.8);f_mstar=6.4e-3*exp(-6.4e3*(m_star-1909.8)t);Fm_star=exp(-t);nq=norminv(Fm_star);dm_star=normpdf(nq)/f_mstar;um_star=m_star-nq*dm_star;D=sqrt(f_star*d_z)2+(z_star*df_star)*2+(dm_star)2);bate_2=(f_star
21、*u_z+z_star*uf_star-f_star*z_star-um_star)/Dwhileabs(bate_lbate_2)le4bate_l=bate_2;cos_f=z_star*df_star/D;cos_z=-f_star*d_z/D;cos_m=dm_star/D;f_star=uf_star+cos_f*bate_l*df_starz_star=u_z+cos_z*bate_l*d_zm_star-um_star+cos_m*bate_l*dm_staruf_star=f_star*(llog(f_star)+u_lnf);df_star=d_lnf*f_star;t=ex
22、p(-6.4e3*(m_star-1909.8);f_mstar=6.4e3*exp(-6.4e3*(m_star-1909.8)t);Fm_star=exp(-t);nq=norminv(Fm_star);dm_star=normpdf(nq)/f_mstar;um_star=m_star-nq*dm_star;D=Sqrt(f_star*d_z)2+(z_star*df_star)2+(dm_star)2);bate_2=(f_star*u_z+z_star*uf_star-f_star*z_star_um_star)/Dendpf=normcdf(-bate_2)P1425.4clear
23、all;u_y=12.5;d_y=12.5*0125;u_x=24;d_x=24*0.15;u_lny=log(12.5sqrt(l+0.1252);d_lny=sqrt(log(l+0.1252);y_star=u_y;x_star=u_x;uy_star=y_star*(llog(y_star)+u_lny);dy_star=d_lny*y_star;t=exp(-0.356*(x_star22.379);f_xstar-0.356*exp(0.356*(x_star22.379)t);Fx_star=exp(t);nq=norminv(Fx_star);dx_star-normpdf(n
24、q)f-xstar;ux_star=x_starnq*dx_star;bate_l=(3*uy_star-ux_star)/sqrt(3*dy_star)2+dx-star2);cosy_star=dy_star/sqrt(3*dy_star)2+dx_star2);cosx_star-dx_star/sqrt(3*dy_star)2+dx_star2);y_star=uy_star+cosy_star*bate_l*dy_star;x_star=ux_star+cosx_star*bate_l*dx_star;uy_star=y_star*(llog(y_star)+u_lny);dy_st
25、ar=d_lny*y_star;t=exp(0.356*(x_star22.379);f_xstar=0.356*exp(0.356*(x_star22.379)t);Fx_star=exp(t);nq=norminv(Fx_star);dx_star=normpdf(nq)/f_xstar;ux_star=x_starnq*dx_star;bate_2=(3*uy_star-ux_star)/sqrt(3*dy_star)2+dx-star2);whileabs(bate_2bate_l)le4bate_l=bate_2;cosy_star=dy_star/sqrt(3*dy_star)2+
26、dx_star2);cosx_star=dx_star/sqrt(3*dy_star)2+dx_star2);y_star=uy_star+cosy_star*bate_l*dy_starx_star=ux_star+cosx_star*bate_l*dx_staruy_star=y_star*(I-Iog(y_star)+u_lny);dy_star=d_lny*y_star;t=exp(-0.356*(x_star22.379);f_xstar=O.356*cxp(-0356*(x_star-22.379)t);Fx_star=exp(-t);nq=norminv(Fx_star);dx_
27、star=normpdf(nq)/f_xstar;ux_star=x_star_nq*dx_star;bate_2=(3*uy_star-ux_star)/sqrt(3*dy_star)2+dx_star2)endpf=normcdf(-bate_2)附件3:Homework3例题6.7clear;clc;symsmu_Rmu_Qmu_Rkmu_Qkdelta三O.1,O.12;beta_T=3.O;dgHE,Tj;k=l;mu_k=muRk,muQk;sigma_k=delta.*mu_k;alpha_l=5,2;alpha_2=4,4;i=O;whileabs(alpha_2(1)-alp
28、ha_l(1)0.OOli=i+l;alpha_2=alpha_l;mu_R二k*mu_Q;mu=mu_R,mu_Q;sigma=delta,*mu;%计算余弦G=dg.*sigma;alpha=-Gsqrt(sum(G.2);alpha-l=subs(alpha,mu_Q,1);X(l,i)=alpha,l(l)i)=alpha_l;断十算设计点的坐标值r=mu_k+alpha_l.*beta_T.*sigma_k;rl=subs(r(1),mu_Rk,1),subs(r(2),mu_Qk,1);k=rl(2)rl(l);endfprintf(,alpha_R=%.4f11,alpha_l(
29、1)fprintf(,alpha_Q=%.4f11,alpha_l(2)例题6.3clearclcsymsRkmu_Rmu_NG=50;sigma_NG=3.5;mu_NL=70;sigma_NL=20;mu_R=1.33*Rk;sigma_R=O.17*mu_R;%此处没赋值V_R=017;%变异系数p二O.02;R_gk=O.31;R_ak三O.01;beta_T=3.2;dg=l,-l,-lj%Z=R-N_G-N_L%初始化alpha_l=5,2;alpha_2=4,4;X=mu_NG+mu_NL,mu_NG,mu_NL;i=0;whileabs(alpha_2(1)-alpha_l(1
30、)0.OOli三i+l;X(i)=x(l);Xi)=x(2);X(3,i)-x(3);alpha_2=alpha_l;sigma_nR=x(l)*sqrt(log(l+0.172);a=pi(sqrt(6)*sigma_NL);u=mu_NL0.5772/a;Fq=exp(exp(a*(x(3)u);f_q=a*(exp(a*(x(3)-U)-CXP(a*(x(3)u);sigma_nNL二(l/f_q)*normpdf(norminv(F_q);mu_nNL二x(3)-sigma_nNL*norminv(F_q);sigma=sigma_nR,sigma_NG,sigma_nNL;mu=1,
31、mu_NG,mu_nNL;%计算奈弦G三dg*sigma;alpha_l=Gsqrt(sum(G.2);X(4,i)三alpha-l(D;X(5,i)=alpha_l(2);%计算设仆点的坐标值r=mu+alpha_L*beta_T.*sigma;xl二r(2)+r(3),r(2),r(3);x=xl;end%计算最后的R值R三x(l);%确定mu_Rmu_nR=R-sigma_nR*beta_T*alpha_l(1);mu_R=sqrt(1+VR2)*exp(mu_nR/R-1+Iog(R);%痂定R_KR_K=mu_R/1.33;%确定A_gkA_gk=R_K/(R_ak/R_gk*l/p
32、+l)*R_gk)7.参考文献1中华人民共和国国家标准.工程结构可靠性设计统一标准(GB50153-2023),北京:中国建筑工业出版社,2023.2中华人民共和国国家标准.建筑结构可靠度设计统一标准(GB50068-2001),北京:中国建筑工业出版社,200L3张明著.结构可靠度分析一方法与程序.北京:科学出版社,2023年.4李国强等编著.工程结构荷载与可靠度设计原理(第三版).北京:中国建筑工业出版社,2005.5贡金鑫,魏巍巍工程结构可靠性设计原理.北京:机械工业出版社,2007.6Nowak,A.S.,andK.R.Collins(2000).ReliabilityofStructures.McGraw-Hill,NewYork,NY.张川导读,重庆:重庆大学出版社,2005年3月.