Hello all,
I am trying to solve the eigenvalue problem for two connected cylinders with different material properties. First of all I tried to solve it in 2D space, here is my code:
structuralModel = createpde('structural','modal-planestrain');% circles
C1 = [1,0.5,-0.25,0.25]';C1 = [C1;zeros(10 - length(C1),1)];C2 = [1,0.5,-0.25,0.20]';C2 = [C2;zeros(10 - length(C2),1)];C3 = [1,0.5,-0.25,0.18]';C3 = [C3;zeros(10 - length(C3),1)];% geometry from edges
gm = [C1,C2,C3];sf = '(C1-C2)+(C2-C3)';ns = char('C1','C2','C3');ns = ns';g = decsg(gm,sf,ns);geometryFromEdges(structuralModel,g);% subplot(3,1,1)
pdegplot(structuralModel,'Facelabels','on','EdgeLabels','on') % ,'EdgeLabels','on',
axis equal% material properties
structuralProperties(structuralModel,'Face',1,'YoungsModulus',200E9,'PoissonsRatio',0.3,'MassDensity',2.7E-6);structuralProperties(structuralModel,'Face',2,'YoungsModulus',110E9,'PoissonsRatio',0.28,'MassDensity',8.7E-6);% mesh
const_h_max = 0.005;mesh = generateMesh(structuralModel,'Hmax',const_h_max);subplot(3,1,2)pdeplot(mesh)% solving
eigen = solve(structuralModel,'FrequencyRange',[20,100]*2*pi);
Error code:
Error using matlab.internal.math.lanczosFactorizations failed possibly because the problem is ill-posed.Error in pde.StructuralModel/solveStructuralEigenvalue (line 76)[v,l] = matlab.internal.math.lanczos(K,M,opts);Error in pde.StructuralModel/solve (line 347) R = solveStructuralEigenvalue(self,argsToPass{:});
1.Is there any possibility at all to do the modal analysis for two bodies (with different material properties)?
2.did I forget any boundary conditions?
Thanks in advance and best regards
Robert
Best Answer