matlab code for eigenvalue problem

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alireza amiri
alireza amiri 2017-10-1
回答: Hank 2017-11-2
i need to solve eigenvalue problem for wave propagation in functionally graded rod functionally graded material composed of 2 or more other material in this problem,this rod composed of two material i have all of Initial values but i cant wrote matlab code for it
The problem is as follows: A=[A11,A12,A13;A21,A22,A23;A31,A32,A33] P=[pm1;pm2;pm3] M=[Mj,0,0;0,Mj,0;0,0,Mj]
A*P=(c^2)*M*P c is the eigen value and pmi are eigen vector
A11=(1/kH)^l*((C11^(l)*I3^l+2)+((l+1)*C11^(l)*I2^l+1)+((lC12^(l)-C22^(l))*I1(m)^l)-n^2*C66^(l)*I1(m)^l-C55^(l)*I1(m)^l+2+C11^(l)*K2(m)^l+2+C12^(l)*K1(m)^l+1)
A12=(1/kH)^l*((i*n*(C12^(l)+C66^(l))*I2(m)^l+1)-(i*n*(C22^(l)+C66^(l)-l*C12^(l))*I1(m)^l)+(i*n*C12^(l)*K1(m)^l+1))
A13=(1/kH)^l*((-i*(C55^(l)+C13^(l))*I2(m)^l+2)-(i*((1+l)*C13^(l)-C23^(l))*I1(m)^l+1)-i*C13^(l)*K1(m)^l+2)
A21=(1/kH)^l*((i*n*(C12^(l)+C66^(l))*I2(m)^l+1)+(i*n*((1+l)*C66^(l)+C22^(l))*I1(m)^l)+(i*n*C66^(l)*K1(m)^l+1))
A22=(1/kH)^l*((C66^(l)*I3(m)^l+2)+((1+l)*C66^(l)*I2(m)^l+1)-((1+l)*C66^(l)*I1(m)^l)-(n^2*C22^(l)*I1(m)^l)-(C44^(l)*I1(m)^l+2)+(C66^(l)*K2(m)^l+2)-(C66^(l)*K1(m)^l+1))
A23=(1/kH)^l*(n*(C44^(l)+C23^(l))*I1(m)^l+1)
A31=(1/kH)^l*((-i(C13^(l)+C55^(l))*I2(m)^l+2)-i(((1+l)*C55^(l)+C23^(l))*I1(m)^l+1)-i*C55^(l)*K1(m)^l+2)
A32=(1/kH)^l*(n*(C44^(l)+C23^(l))*I1(m)^l+1)
A33=(1/kH)^l*((C55^(l)*I3(m)^l+2)-n^2*(C44^(l)*I1(m)^l)-(C33^(l)*I1(m)^l+2)+((1+l)*C55^(l)*I2(m)^l+1)+(C55^(l)*K2(m)^l+2))
Mj=ro^(l)*(1/kH)^l*I1(m)^l+2
I1(m)^l=KR1/2*((g(m+1)*I1(m+1)^l-1)+(I1(m)^l-1)+(g(m)*I1(m-1)^l-1))
I2(m)^l=KR1/2*sqrt(2m+1)*((sqrt(2m+1)*I1(m-1)^l)+(sqrt(2m-5)*I1(m-3)^l)+(sqrt(2m-9)*I1(m-5)^l)+...)
I3(m)^l=KR1/2*sqrt(2m+1)*((sqrt(2m+1)*I2(m-1)^l)+(sqrt(2m-5)*I2(m-3)^l)+(sqrt(2m-9)*I2(m-5)^l)+...)
K1(m)^l=Qj(KR1)*(KR1)^l*Qm(KR1)
K2(m)^l=KR1/2*sqrt(2m+1)*((sqrt(2m+1)*K1(m-1)^l)+(sqrt(2m-5)*K1(m-3)^l)+(sqrt(2m-9)*K1(m-5)^l)+...)
%l run from 0 to 3
Qm(q1)=sqrt((2m+1)/KR1*Pm*(2q1-KR1)/KR1) %Pm,mth Legendre polynomial Qm(KR1)=sqrt((2m+1)/KR1*Pm %Pm,mth Legendre polynomial
g(m)=m/(2m-1)*(2m+1) %m run from 0 to 8
Valid values:
C11^(0)=46.8419
C11^(1)=-9.4828
C11^(2)=0.8735
C11^(3)=-0.2319
C12^(0)=9.2556
C12^(1)=2.8590
C12^(2)=0.0797
C12^(3)=-0.1936
C44^(0)=18.7909
C44^(1)=-6.1663
C44^(2)=0.3938
C44^(3)=-0.0185
ro^(0)=-3.4260
ro^(1)=5.7960
ro^(2)=0
ro^(3)=0
C22=0
C13=0
C55=0
C66=0
C23=0
C33=0
R1=H=0.2m
0<q1<KR1
KR1=KH=0,1,2,3,...,20
n=0,1
i=sqrt(-1)

回答(1 个)

Hank
Hank 2017-11-2
Try simplifying the problem you're having instead of dumping equations. I went cross-eyed and I don't know what you want.

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