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itmkurs_lab1

PURPOSE ^

Script to computer exercises 1

SYNOPSIS ^

This is a script file.

DESCRIPTION ^

 ITMKURS_LAB1 Script to computer exercises 1
  
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %Analysis of Load Data
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  A Stochastic Load Process
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 %Measured data

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

001 %ITMKURS_LAB1 Script to computer exercises 1
002 % 
003 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
004 %
005 %%Analysis of Load Data
006 %
007 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
008 % A Stochastic Load Process
009 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
010 %
011 %%Measured data
012 %
013 
014 load deep.dat
015 x = deep;
016 plot(x(:,1),x(:,2))
017 plot(x(1:1000,1),x(1:1000,2))
018 
019 
020 T=x(end,1)-x(1,1);
021 
022 whos
023 
024 
025 tp = dat2tp(x);
026 plot(x(:,1),x(:,2),tp(:,1),tp(:,2),'.-')
027 axis([0 100 -20 20])
028 
029 tp1 = dat2tp(x,1);
030 plot(x(:,1),x(:,2),tp(:,1),tp(:,2),tp1(:,1),tp1(:,2))
031 axis([0 100 -20 20])
032 
033 
034 lc = tp2lc(tp);
035 lc(:,2)=lc(:,2)/T;
036 plot(lc(:,1),lc(:,2))
037 semilogx(lc(:,2),lc(:,1))
038 
039 
040 m=mean(x(:,2));
041 f0 = interp1(lc(:,1),lc(:,2),m,'linear');
042 f0
043 
044 
045 
046 extr0=length(tp)/2/T;
047 alfa=f0/extr0
048 
049 %
050 %%Gaussian process as a model for the deep water data
051 %
052 
053 
054 wnormplot(x(:,2))
055 
056 
057 
058 S = dat2spec(deep);
059 wspecplot(S);
060 
061 S
062 plot(S.w,S.S)
063 
064 
065 
066 lam = spec2mom(S,4); L0=lam(1); L2=lam(2); L4=lam(3);
067 
068 
069 f0=1/(2*pi)*sqrt(L2/L0)
070 ux = -20:0.1:20;
071 ricex = f0*exp(-ux.*ux./(2*L0));
072 plot(lc(:,1),lc(:,2),'-',ux,ricex,'--')
073 semilogx(lc(:,2),lc(:,1),'-',ricex,ux,'--')
074 
075   
076 
077 
078 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
079 % Cycle counts
080 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
081 %---------------------
082 %Cycle Counts
083 %---------------------
084 
085 proc = x(1:500,:);
086 democc
087 
088 RFC = tp2rfc(tp);
089 mM = tp2mm(tp);
090 
091 
092 subplot(1,2,1), ccplot(RFC)
093 subplot(1,2,2), ccplot(mM)
094 
095 
096 ampRFC = cc2amp(RFC);
097 ampmM = cc2amp(mM);
098 subplot(1,2,1), hist(ampRFC)
099 subplot(1,2,2), hist(ampmM)
100 
101 
102 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
103 % SN-data
104 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
105 %
106 %%Calculation of damage intensity}
107 %
108 
109 beta=3.2; gam=5.5E-10;
110 d_beta=cc2dam(RFC,beta)/T;
111 time_fail=1/gam/d_beta/3600 %in hours of the specific storm
112 
113 
114 %
115 %%Additional exercises, Optional
116 %
117 
118 load SN
119 
120 plot(N,s,'o')
121 axis([0 14e5 5 35 ])
122 loglog(N,s,'o')
123 
124 
125 wnormplot(reshape(log(N),8,5))
126 
127 
128 [e0,beta0,s20] = snplot(s,N,12)
129 [e0,beta0,s20] = snplot(s,N,14)
130 e0    = 5.5361e-10
131 beta0 = 3.2286
132 s20   = 0.0604
133 
134 %
135 %%Calculation of the 95\% quantile for the fatigue life time
136 %
137 %%Fatigue life distribution under variable random load
138 %
139 
140 D0 = e0*cumsum((RFC(:,2)-RFC(:,1)).^beta0);
141 plot(D0)
142 
143       
144 beta = 3:0.1:8;
145 DRFC = cc2dam(RFC,beta);
146 dRFC = DRFC/T
147 plot(beta,dRFC)
148 
149 
150 help ftf
151 [t0,F0] = ftf(e0,cc2dam(RFC,beta0)/T,s20,0.5,1);
152 
153 [t1,F1] = ftf(e0,cc2dam(RFC,beta0)/T,s20,0,1);
154 [t2,F2] = ftf(e0,cc2dam(RFC,beta0)/T,s20,5,1);
155 plot(t0,F0,t1,F1,t2,F2)
156 
157 
158 taRFC = exp(-1.96*sqrt(0.06))/e0./dRFC;
159 DmM = cc2dam(mM,beta);
160 dmM = DmM/T
161 tamM = exp(-1.96*sqrt(0.06))/e0./dmM;
162 plot(beta,taRFC,beta,tamM,'r')
163 
164 %
165 %%Crack growth data}  %%%%%%%%%%%%%
166 %
167 
168 
169 
170 
171 clear
172 load virkler
173 
174 plot(v(:,2),v(:,1))
175 
176 
177 plot(v(:,2:69),v(:,1),'b-')
178 
179 
180 
181 N = alevel(v,15);
182 
183 plot(N,ones(1,length(N)),'o')
184 
185 a = nlevel(v,2e5);
186 plot(a,ones(1,length(a)),'o')
187 
188 
189

Mathematical Statistics
Centre for Mathematical Sciences
Lund University with Lund Institute of Technology

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