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Euler Bernoulli beam with cubic spring and damper and internal resonance

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Bernoulli beam with 1:3 internal resonance

In this example, we consider a cantilever beam with a nonlinear support spring at its free end. The linear part of the stiffness of the support spring is tuned such that 1:3 internal resonance occurs between the first two bending modes.

We then extract the forced response curve for both periodic and quasi-periodic response using SSM reduction. In particular, both two- and three-dimensional invariant tori will be computed. Dynamical System Setup Numerical experiments show that a near 1:3 internal resonance occurs at . In the following computations, we set the number of beam elements to be 40. The bifurcations observed here are persistent when the number of elements is increased.

nElements = 40;
kLinear = 27;
kNonlinear = 60;
[M,C,K,fnl] = build_model(nElements,kLinear,kNonlinear);
order = 2;
DS = DynamicalSystem(order);
set(DS,'M',M,'C',C,'K',K,'fnl',fnl);
set(DS.Options,'Emax',10,'Nmax',10,'notation','multiindex','RayleighDamp',false)

Linear Modal analysis

[V,D,W] = DS.linear_spectral_analysis();
 The first 10 nonzero eigenvalues are given as 
   1.0e+02 *

  -0.0000 + 0.1560i
  -0.0000 - 0.1560i
  -0.0002 + 0.4658i
  -0.0002 - 0.4658i
  -0.0019 + 1.2377i
  -0.0019 - 1.2377i
  -0.0072 + 2.4119i
  -0.0072 - 2.4119i
  -0.0198 + 3.9821i
  -0.0198 - 3.9821i

Add forcing

Excitation of the form is applied such that only the first linear mode is activated if damping and nonlinear internal forces are removed.

[vs,om_nat] = eigs(K,M,2,'smallestabs');
om_nat = sqrt(diag(om_nat));
f_0 = (om_nat(1))^2*M*vs(:,1);
epsilon = 0.002;
kappas = [-1; 1];
coeffs = [f_0 f_0]/2;
DS.add_forcing(coeffs, kappas, epsilon);

SSM Computation

We now choose a master spectral subspace over which the SSM is constructed. Since the first two modepairs are in resnonance, both have to be included into the subspace. The constructed manifold will thus be 4-dimensional.

S = SSM(DS);
set(S.Options, 'reltol', 0.1,'notation','multiindex')

resonant_modes = [1 2 3 4];
mFreq  = [1 3];
order  = 7; % Approximation order
outdof = [2*round(nElements/2)-1; 2*nElements-1];
n = length(M);

Continuation of equilibria

SSM_isol2ep: continuation of equilibrium points Each equilibrium here corresponds to a periodic orbit of the full system.

freqRange  = [15.30 15.95];
set(S.FRCOptions, 'SampStyle','cocoBD');                       % sampling style
set(S.FRCOptions, 'nCycle',5000, 'initialSolver', 'fsolve');   % solver for initial solution
set(S.contOptions, 'h_min',1e-3,'h_max',0.01,'NSV',10,'bi_direct',true,'PtMX',100);  % continuation setting
set(S.FRCOptions, 'coordinates', 'cartesian');                 % two representations

isolid = ['isol-',num2str(nElements),'-',num2str(order),'c'];
startep = tic;
FRC = S.SSM_isol2ep(isolid,resonant_modes,order,mFreq,'freq',freqRange,outdof);
timings.epFRC = toc(startep);
The master subspace contains the following eigenvalues
 
lambda1 == - 0.00103059 + 15.6033i
 
lambda2 == (-0.00103059) - 15.6033i
 
lambda3 == - 0.0238945 + 46.5766i
 
lambda4 == (-0.0238945) - 46.5766i
 
(near) outer resonance detected for the following combinations of master eigenvalues
 They are in resonance with the following eigenvalues of the slave subspace 
 
0*lambda1 + 1*lambda2 + 3*lambda3 + 0*lambda4 == - 0.1886207 + 123.7738i
 
2*lambda1 + 0*lambda2 + 2*lambda3 + 0*lambda4 == - 0.1886207 + 123.7738i
 
0*lambda1 + 1*lambda2 + 4*lambda3 + 1*lambda4 == - 0.1886207 + 123.7738i
 .
 .
 .
 
 
sigma_out = 1920
(near) inner resonance detected for the following combination of master eigenvalues:
 
0*lambda1 + 2*lambda2 + 1*lambda3 + 0*lambda4 == lambda1
 
1*lambda1 + 0*lambda2 + 1*lambda3 + 1*lambda4 == lambda1
 
2*lambda1 + 1*lambda2 + 0*lambda3 + 0*lambda4 == lambda1
 
.
.
.

0*lambda1 + 1*lambda2 + 1*lambda3 + 1*lambda4 == lambda2
 
1*lambda1 + 2*lambda2 + 0*lambda3 + 0*lambda4 == lambda2
 
2*lambda1 + 0*lambda2 + 0*lambda3 + 1*lambda4 == lambda2
 
.
.
.

0*lambda1 + 0*lambda2 + 2*lambda3 + 1*lambda4 == lambda3
 
1*lambda1 + 1*lambda2 + 1*lambda3 + 0*lambda4 == lambda3
 
3*lambda1 + 0*lambda2 + 0*lambda3 + 0*lambda4 == lambda3
.
.
.

0*lambda1 + 0*lambda2 + 1*lambda3 + 2*lambda4 == lambda4
 
0*lambda1 + 3*lambda2 + 0*lambda3 + 0*lambda4 == lambda4
 
1*lambda1 + 1*lambda2 + 0*lambda3 + 1*lambda4 == lambda4
.
.
.

sigma_in = 1920
Due to (near) outer resonance, the exisitence of the manifold is questionable and the underlying computation may suffer.
Attempting manifold computation
Manifold computation time at order 2 = 00:00:05
Estimated memory usage at order  2 = 1.76E-01 MB
Manifold computation time at order 3 = 00:00:00
Estimated memory usage at order  3 = 5.95E-01 MB
Manifold computation time at order 4 = 00:00:00
Estimated memory usage at order  4 = 9.22E-01 MB
Manifold computation time at order 5 = 00:00:00
Estimated memory usage at order  5 = 2.34E+00 MB
Manifold computation time at order 6 = 00:00:00
Estimated memory usage at order  6 = 3.51E+00 MB
Manifold computation time at order 7 = 00:00:00
Estimated memory usage at order  7 = 7.15E+00 MB

Equation solved.

fsolve completed because the vector of function values is near zero
as measured by the value of the function tolerance, and
the problem appears regular as measured by the gradient.


 Run='isol-40-7c.ep': Continue equilibria along primary branch.

    STEP   DAMPING               NORMS              COMPUTATION TIMES
  IT SIT     GAMMA     ||d||     ||f||     ||U||   F(x)  DF(x)  SOLVE
   0                          2.49e-13  2.21e+01    0.0    0.0    0.0

 STEP      TIME        ||U||  LABEL  TYPE            om         Rez1         Rez2         Imz1         Imz2          eps
    0  00:00:00   2.2066e+01      1  EP      1.5603e+01  -2.6828e-02  -1.0138e-02   2.9467e-03  -1.0906e-03   2.0000e-03
   10  00:00:01   2.2038e+01      2  SN      1.5583e+01  -2.2559e-02  -1.3565e-02   6.8869e-03  -7.9042e-03   2.0000e-03
   10  00:00:01   2.2038e+01      3  FP      1.5583e+01  -2.2559e-02  -1.3565e-02   6.8870e-03  -7.9042e-03   2.0000e-03
   10  00:00:01   2.2038e+01      4          1.5583e+01  -2.2552e-02  -1.3479e-02   6.9850e-03  -8.2648e-03   2.0000e-03
   20  00:00:01   2.2042e+01      5          1.5586e+01  -2.3687e-02  -8.8916e-03   8.1207e-03  -1.4535e-02   2.0000e-03
   27  00:00:02   2.2048e+01      6  HB      1.5590e+01  -2.6008e-02  -1.7629e-03   8.0273e-03  -1.6839e-02   2.0000e-03
   30  00:00:02   2.2050e+01      7          1.5592e+01  -2.7530e-02   2.2132e-03   7.5740e-03  -1.6290e-02   2.0000e-03
   36  00:00:02   2.2052e+01      8  FP      1.5593e+01  -2.9510e-02   6.3700e-03   6.6270e-03  -1.3980e-02   2.0000e-03
   36  00:00:02   2.2052e+01      9  SN      1.5593e+01  -2.9510e-02   6.3701e-03   6.6270e-03  -1.3980e-02   2.0000e-03
   40  00:00:02   2.2051e+01     10          1.5592e+01  -3.0646e-02   8.1248e-03   5.8682e-03  -1.1939e-02   2.0000e-03
   50  00:00:03   2.2043e+01     11          1.5587e+01  -3.2447e-02   9.4371e-03   4.0091e-03  -7.2101e-03   2.0000e-03
   51  00:00:03   2.2043e+01     12  HB      1.5587e+01  -3.2449e-02   9.4368e-03   4.0069e-03  -7.2048e-03   2.0000e-03
   60  00:00:03   2.1979e+01     13          1.5542e+01  -3.1578e-02   4.9750e-03   8.3728e-04  -1.0590e-03   2.0000e-03
   70  00:00:04   2.1879e+01     14          1.5471e+01  -2.7616e-02   1.8536e-03   1.9365e-04  -1.6927e-04   2.0000e-03
   80  00:00:04   2.1780e+01     15          1.5400e+01  -2.4185e-02   8.3302e-04   9.4228e-05  -4.8263e-05   2.0000e-03
   90  00:00:04   2.1680e+01     16          1.5330e+01  -2.1220e-02   4.1705e-04   6.2095e-05  -1.7790e-05   2.0000e-03
   95  00:00:05   2.1637e+01     17  EP      1.5300e+01  -2.0093e-02   3.1835e-04   5.3972e-05  -1.2219e-05   2.0000e-03

 STEP      TIME        ||U||  LABEL  TYPE            om         Rez1         Rez2         Imz1         Imz2          eps
    0  00:00:05   2.2066e+01     18  EP      1.5603e+01  -2.6828e-02  -1.0138e-02   2.9467e-03  -1.0906e-03   2.0000e-03
    9  00:00:05   2.2154e+01     19  HB      1.5665e+01  -3.2831e-02  -6.0116e-03   1.1299e-03  -2.1552e-04   2.0000e-03
   10  00:00:05   2.2166e+01     20          1.5673e+01  -3.3414e-02  -5.7526e-03   1.0513e-03  -1.8388e-04   2.0000e-03
   20  00:00:06   2.2265e+01     21          1.5744e+01  -3.7595e-02  -4.5542e-03   7.5339e-04  -4.9426e-05   2.0000e-03
   30  00:00:06   2.2365e+01     22          1.5815e+01  -4.1238e-02  -4.1216e-03   6.9093e-04   4.0189e-06   2.0000e-03
   37  00:00:06   2.2434e+01     23  HB      1.5863e+01  -4.3595e-02  -3.9979e-03   6.9177e-04   2.7121e-05   2.0000e-03
   40  00:00:06   2.2465e+01     24          1.5885e+01  -4.4654e-02  -3.9684e-03   6.9871e-04   3.5975e-05   2.0000e-03
   50  00:00:07   2.2557e+01     25  EP      1.5950e+01  -4.7662e-02  -3.9424e-03   7.3303e-04   5.8408e-05   2.0000e-03
   
the forcing frequency 1.5300e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5302e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5309e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
.
.
.

Continuation of Saddle Node bifurcations

SSM_ep2SN: continuation of SN equilibrium points Continuation of saddle-node bifurcations of periodic orbits.

set(S.contOptions, 'h_min',1e-3,'h_max',0.1);              % continuation setting
epsRange = [1e-4 1e-2];
bd    = coco_bd_read([isolid,'.ep']);
omega = coco_bd_col(bd,'om');
SNlab = coco_bd_labs(bd,'SN');
if ~isempty(SNlab)
    % find the lab with smallest omega
    SNidx = coco_bd_idxs(bd,'SN');
    omSN  = omega(SNidx);
    [~,id]= max(omSN);
    SNlab = SNlab(id);
    SNid = ['SN-',num2str(nElements),'-',num2str(order),'c'];
    S.SSM_ep2SN(SNid,isolid,SNlab,{freqRange,epsRange},outdof);
end
 Run='SN-40-7c.ep': Continue saddle-node equilibria from label 9 of run isol-40-7c.

    STEP   DAMPING               NORMS              COMPUTATION TIMES
  IT SIT     GAMMA     ||d||     ||f||     ||U||   F(x)  DF(x)  SOLVE
   0                          7.53e-09  2.21e+01    0.0    0.0    0.0

 STEP      TIME        ||U||  LABEL  TYPE            om          eps         Rez1         Rez2         Imz1         Imz2
    0  00:00:00   2.2074e+01      1  EP      1.5593e+01   2.0000e-03  -2.9510e-02   6.3701e-03   6.6270e-03  -1.3980e-02
   10  00:00:00   2.2029e+01      2          1.5561e+01   9.9036e-04  -2.0600e-02  -1.8906e-03   5.6106e-03  -9.7657e-03
   14  00:00:01   2.2027e+01      3  FP      1.5559e+01   9.4686e-04  -1.9689e-02  -3.5754e-03   5.5115e-03  -8.9553e-03
   20  00:00:01   2.2033e+01      4          1.5564e+01   1.1144e-03  -1.9811e-02  -7.2148e-03   5.9151e-03  -8.1084e-03
   30  00:00:02   2.2091e+01      5          1.5604e+01   3.2354e-03  -2.5347e-02  -1.8662e-02   7.2287e-03  -8.2799e-03
   36  00:00:02   2.2210e+01      6  EP      1.5689e+01   1.0000e-02  -3.4522e-02  -3.3213e-02   6.8809e-03  -9.5720e-03

 STEP      TIME        ||U||  LABEL  TYPE            om          eps         Rez1         Rez2         Imz1         Imz2
    0  00:00:02   2.2074e+01      7  EP      1.5593e+01   2.0000e-03  -2.9510e-02   6.3701e-03   6.6270e-03  -1.3980e-02
   10  00:00:03   2.2211e+01      8          1.5689e+01   5.9424e-03  -4.7018e-02   2.0847e-02   6.1468e-03  -1.4555e-02
   15  00:00:03   2.2322e+01      9  EP      1.5768e+01   1.0000e-02  -5.8059e-02   2.8255e-02   5.5088e-03  -1.3193e-02
   
the forcing frequency 1.5689e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5673e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5654e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
.
.
.

Continuation of Hopf Bifurcations

SSM_ep2HB: continuation of HB equilibrium points Continuation of Hopf bifurcation of periodic orbits.

HBlab = coco_bd_labs(bd,'HB');
% find the lab with smallest omega
HBidx = coco_bd_idxs(bd,'HB');
omHB  = omega(HBidx);
[~,idx] = sort(omHB);
HBlab1 = HBlab(idx(end-1));
HBid1 = ['HB1-',num2str(nElements),'-',num2str(order),'c'];
S.SSM_ep2HB(HBid1,isolid,HBlab1,{freqRange,epsRange},outdof);
 Run='HB1-40-7c.ep': Continue Hopf equilibria from label 19 of run isol-40-7c.

    STEP   DAMPING               NORMS              COMPUTATION TIMES
  IT SIT     GAMMA     ||d||     ||f||     ||U||   F(x)  DF(x)  SOLVE
   0                          2.95e-09  2.22e+01    0.0    0.0    0.0

 STEP      TIME        ||U||  LABEL  TYPE            om          eps         Rez1         Rez2         Imz1         Imz2
    0  00:00:00   2.2177e+01      1  EP      1.5665e+01   2.0000e-03  -3.2831e-02  -6.0116e-03   1.1299e-03  -2.1552e-04
   10  00:00:01   2.2081e+01      2          1.5597e+01   5.2426e-04  -1.9854e-02  -1.8619e-03   5.6411e-04  -1.9735e-04
   20  00:00:01   2.2068e+01      3          1.5588e+01   3.7197e-04  -1.7116e-02  -1.2255e-03   4.3179e-04  -1.4786e-04
   21  00:00:01   2.2068e+01      4  FP      1.5588e+01   3.7136e-04  -1.7106e-02  -1.2227e-03   4.3124e-04  -1.4744e-04
   30  00:00:02   2.2089e+01      5          1.5603e+01   3.9645e-04  -1.8664e-02  -1.2761e-03   4.5826e-04  -1.0621e-04
   40  00:00:02   2.2170e+01      6          1.5660e+01   6.6994e-04  -2.5800e-02  -2.0332e-03   6.0108e-04  -5.1688e-05
   49  00:00:03   2.2585e+01      7  EP      1.5950e+01   2.7271e-03  -4.9693e-02  -4.6828e-03   6.8387e-04   3.8766e-05

 STEP      TIME        ||U||  LABEL  TYPE            om          eps         Rez1         Rez2         Imz1         Imz2
    0  00:00:03   2.2177e+01      8  EP      1.5665e+01   2.0000e-03  -3.2831e-02  -6.0116e-03   1.1299e-03  -2.1552e-04
    7  00:00:03   2.2401e+01      9  EP      1.5814e+01   1.0000e-02  -5.3016e-02  -1.7501e-02   1.7491e-03  -9.8030e-05
    
the forcing frequency 1.5950e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5926e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5878e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
.
.
.

Investigation of a specific Hopf Bifurcation

Continuation of HB points with the other one as starting point

HBid2 = ['HB2-',num2str(nElements),'-',num2str(order),'c'];
S.SSM_ep2HB(HBid2,isolid,HBlab(idx(2)),{freqRange,epsRange},outdof);
 Run='HB2-40-7c.ep': Continue Hopf equilibria from label 6 of run isol-40-7c.

    STEP   DAMPING               NORMS              COMPUTATION TIMES
  IT SIT     GAMMA     ||d||     ||f||     ||U||   F(x)  DF(x)  SOLVE
   0                          5.25e-08  2.21e+01    0.0    0.0    0.0

 STEP      TIME        ||U||  LABEL  TYPE            om          eps         Rez1         Rez2         Imz1         Imz2
    0  00:00:00   2.2078e+01      1  EP      1.5590e+01   2.0000e-03  -2.6008e-02  -1.7629e-03   8.0273e-03  -1.6839e-02
   10  00:00:00   2.2054e+01      2          1.5575e+01   1.4241e-03  -2.5057e-02   2.3219e-03   6.3372e-03  -1.2466e-02
   20  00:00:01   2.2051e+01      3  FP      1.5573e+01   1.3727e-03  -2.5879e-02   4.6800e-03   5.4331e-03  -1.0510e-02
   20  00:00:01   2.2052e+01      4          1.5573e+01   1.3734e-03  -2.5905e-02   4.7219e-03   5.4177e-03  -1.0476e-02
   30  00:00:02   2.2069e+01      5          1.5581e+01   1.7778e-03  -3.0613e-02   8.5207e-03   4.2172e-03  -7.7110e-03
   40  00:00:02   2.2190e+01      6          1.5635e+01   4.2525e-03  -4.5196e-02   1.4560e-02   3.2436e-03  -5.4609e-03
   50  00:00:03   2.2345e+01      7          1.5682e+01   6.7451e-03  -5.4499e-02   1.8082e-02   2.9696e-03  -4.9282e-03
   60  00:00:04   2.2533e+01      8          1.5724e+01   9.1169e-03  -6.1379e-02   2.0852e-02   2.8586e-03  -4.7552e-03
   64  00:00:04   2.2615e+01      9  EP      1.5740e+01   1.0000e-02  -6.3625e-02   2.1820e-02   2.8394e-03  -4.7392e-03

 STEP      TIME        ||U||  LABEL  TYPE            om          eps         Rez1         Rez2         Imz1         Imz2
    0  00:00:04   2.2078e+01     10  EP      1.5590e+01   2.0000e-03  -2.6008e-02  -1.7629e-03   8.0273e-03  -1.6839e-02
   10  00:00:05   2.2212e+01     11          1.5657e+01   5.1508e-03  -3.4457e-02   4.1935e-03   9.3697e-03  -2.8826e-02
   20  00:00:05   2.2371e+01     12          1.5712e+01   7.9793e-03  -4.1785e-02   1.6229e-02   8.9527e-03  -3.1306e-02
   28  00:00:06   2.2507e+01     13  EP      1.5748e+01   1.0000e-02  -4.6462e-02   2.3175e-02   8.5302e-03  -3.0698e-02
   
the forcing frequency 1.5740e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5736e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5732e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
.
.
.

SSM_HB2po: continuation of periodic orbits from HB point

set(S.contOptions, 'h_max',0.3,'PtMX',100, 'bi_direct', false, 'NSV', 1,'NAdapt',5);                    % continuation setting
po1id = ['po1-',num2str(nElements),'-',num2str(order),'c'];
startpo = tic;
set(S.FRCOptions,'parSamps',15.75);
S.SSM_HB2po(po1id,isolid,HBlab1,'freq',freqRange,[outdof; outdof+n],'saveICs');
timings.po1FRC = toc(startpo);
 Run='po1-40-7c.po': Continue periodic orbits born from a HB point with label 19 of run isol-40-7c.

    STEP   DAMPING               NORMS              COMPUTATION TIMES
  IT SIT     GAMMA     ||d||     ||f||     ||U||   F(x)  DF(x)  SOLVE
   0                          3.05e-05  3.50e+01    0.0    0.0    0.0
   1   1  1.00e+00  1.55e-03  2.48e-06  3.50e+01    0.0    0.0    0.0
   2   1  1.00e+00  1.20e-03  1.49e-06  3.50e+01    0.0    0.0    0.0
   3   1  1.00e+00  7.68e-04  6.08e-07  3.50e+01    0.0    0.0    0.0
   4   1  1.00e+00  4.70e-04  2.27e-07  3.50e+01    0.0    0.0    0.0
   5   1  1.00e+00  2.47e-04  6.25e-08  3.50e+01    0.0    0.1    0.0
   6   1  1.00e+00  8.66e-05  7.71e-09  3.50e+01    0.0    0.1    0.0
   7   1  1.00e+00  1.14e-05  1.34e-10  3.50e+01    0.0    0.1    0.0
   8   1  1.00e+00  1.95e-07  3.88e-14  3.50e+01    0.0    0.1    0.0

 STEP      TIME        ||U||  LABEL  TYPE            om    po.period          eps
    0  00:00:00   3.4959e+01      1  EP      1.5665e+01   1.9122e+01   2.0000e-03
    1  00:00:01   3.4959e+01      2          1.5665e+01   1.9122e+01   2.0000e-03
    2  00:00:01   3.4958e+01      3          1.5665e+01   1.9121e+01   2.0000e-03
    3  00:00:01   3.4957e+01      4          1.5665e+01   1.9120e+01   2.0000e-03
    4  00:00:01   3.4956e+01      5          1.5665e+01   1.9119e+01   2.0000e-03
    5  00:00:01   3.4954e+01      6          1.5665e+01   1.9117e+01   2.0000e-03
    6  00:00:01   3.4951e+01      7          1.5665e+01   1.9115e+01   2.0000e-03
    .
    .
    .
   77  00:00:11   3.3423e+01     78          1.5744e+01   1.7625e+01   2.0000e-03
   78  00:00:11   3.3281e+01     79          1.5749e+01   1.7485e+01   2.0000e-03
   79  00:00:11   3.3255e+01     80  PS      1.5750e+01   1.7460e+01   2.0000e-03
   79  00:00:11   3.3067e+01     81          1.5757e+01   1.7273e+01   2.0000e-03
   80  00:00:11   3.2855e+01     82          1.5766e+01   1.7062e+01   2.0000e-03
   81  00:00:12   3.2644e+01     83          1.5775e+01   1.6850e+01   2.0000e-03
   82  00:00:12   3.2436e+01     84          1.5785e+01   1.6639e+01   2.0000e-03
   83  00:00:12   3.2231e+01     85          1.5796e+01   1.6427e+01   2.0000e-03
   84  00:00:12   3.2028e+01     86          1.5808e+01   1.6216e+01   2.0000e-03
   85  00:00:12   3.1828e+01     87          1.5820e+01   1.6005e+01   2.0000e-03
   86  00:00:12   3.1630e+01     88          1.5834e+01   1.5794e+01   2.0000e-03
   87  00:00:12   3.1434e+01     89          1.5848e+01   1.5584e+01   2.0000e-03
   88  00:00:13   3.1241e+01     90          1.5861e+01   1.5374e+01   2.0000e-03
   89  00:00:13   3.1219e+01     91          1.5862e+01   1.5351e+01   2.0000e-03
   90  00:00:13   3.1214e+01     92          1.5863e+01   1.5346e+01   2.0000e-03
   91  00:00:13   3.1212e+01     93          1.5863e+01   1.5344e+01   2.0000e-03
   92  00:00:13   3.1212e+01     94          1.5863e+01   1.5343e+01   2.0000e-03
   93  00:00:14   3.1211e+01     95          1.5863e+01   1.5343e+01   2.0000e-03
   94  00:00:14   3.1211e+01     96          1.5863e+01   1.5343e+01   2.0000e-03
   95  00:00:14   3.1211e+01     97          1.5863e+01   1.5342e+01   2.0000e-03
   96  00:00:14   3.1211e+01     98          1.5863e+01   1.5342e+01   2.0000e-03
   97  00:00:14   3.1211e+01     99  FP      1.5863e+01   1.5342e+01   2.0000e-03
   97  00:00:14   3.1211e+01    100          1.5863e+01   1.5342e+01   2.0000e-03
   98  00:00:14   3.1211e+01    101  BP      1.5863e+01   1.5342e+01   2.0000e-03
   98  00:00:14   3.1211e+01    102          1.5863e+01   1.5342e+01   2.0000e-03
   99  00:00:14   3.1211e+01    103          1.5863e+01   1.5343e+01   2.0000e-03
  100  00:00:14   3.1211e+01    104  EP      1.5863e+01   1.5343e+01   2.0000e-03
  
Constructing torus in reduced dynamical system
 
Interpolation at (omega,epsilon) = (1.566497e+01,2.000000e-03)
Interpolation at (omega,epsilon) = (1.566498e+01,2.000000e-03)
Interpolation at (omega,epsilon) = (1.566499e+01,2.000000e-03)
.
.
.
Illustration of the construction of torus in reduced dynamical system
Visualization of torus at (omega,epsilon)=(1.573303e+01,2.000000e-03)

 FRCs from ='po1-40-7c.po': generating torus in physical domain.
the forcing frequency 1.5665e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5665e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5665e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
.
.
.

 

Continuation of periodic orbits from another HB point

HBlab2 = HBlab(idx(2));
po2id = ['po2-',num2str(nElements),'-',num2str(order),'c'];
set(S.contOptions, 'h_max',0.05, 'PtMX', 70, 'NSV', 2, 'bi_direct', false, 'NAdapt', 10);              % continuation setting
startpo = tic;
set(S.FRCOptions,'parSamps',[15.589, 15.5905]);
S.SSM_HB2po(po2id,isolid,HBlab2,'freq',freqRange,[outdof; outdof+n],'saveICs');
timings.po2FRC = toc(startpo);
 Run='po2-40-7c.po': Continue periodic orbits born from a HB point with label 6 of run isol-40-7c.

    STEP   DAMPING               NORMS              COMPUTATION TIMES
  IT SIT     GAMMA     ||d||     ||f||     ||U||   F(x)  DF(x)  SOLVE
   0                          3.78e-05  2.95e+01    0.0    0.0    0.0
   1   1  1.00e+00  6.42e-04  3.68e-07  2.95e+01    0.0    0.0    0.0
   2   2  5.00e-01  1.37e-03  5.82e-07  2.95e+01    0.0    0.0    0.0
   3   1  1.00e+00  9.75e-04  8.18e-07  2.95e+01    0.0    0.0    0.0
   4   1  1.00e+00  3.23e-04  8.99e-08  2.95e+01    0.0    0.0    0.0
   5   1  1.00e+00  6.79e-05  3.96e-09  2.95e+01    0.0    0.1    0.0
   6   1  1.00e+00  2.35e-06  4.76e-12  2.95e+01    0.0    0.1    0.0
   7   1  1.00e+00  3.57e-09  5.83e-16  2.95e+01    0.0    0.1    0.0

 STEP      TIME        ||U||  LABEL  TYPE            om    po.period          eps
    0  00:00:00   2.9541e+01      1  EP      1.5590e+01   1.3902e+01   2.0000e-03
    2  00:00:00   2.9539e+01      2          1.5590e+01   1.3900e+01   2.0000e-03
    4  00:00:01   2.9538e+01      3          1.5590e+01   1.3898e+01   2.0000e-03
    6  00:00:01   2.9535e+01      4          1.5590e+01   1.3896e+01   2.0000e-03
    8  00:00:01   2.9531e+01      5          1.5590e+01   1.3891e+01   2.0000e-03
   10  00:00:01   2.9522e+01      6          1.5590e+01   1.3881e+01   2.0000e-03
   12  00:00:02   2.9501e+01      7          1.5590e+01   1.3859e+01   2.0000e-03
   14  00:00:02   2.9449e+01      8  PS      1.5591e+01   1.3803e+01   2.0000e-03
   14  00:00:02   2.9448e+01      9          1.5591e+01   1.3802e+01   2.0000e-03
   16  00:00:02   2.9382e+01     10          1.5591e+01   1.3732e+01   2.0000e-03
   18  00:00:02   2.9317e+01     11          1.5591e+01   1.3662e+01   2.0000e-03
   20  00:00:03   2.9273e+01     12  FP      1.5591e+01   1.3614e+01   2.0000e-03
   20  00:00:03   2.9273e+01     13  SN      1.5591e+01   1.3614e+01   2.0000e-03
   20  00:00:03   2.9251e+01     14          1.5591e+01   1.3591e+01   2.0000e-03
   22  00:00:03   2.9186e+01     15          1.5591e+01   1.3521e+01   2.0000e-03
   24  00:00:04   2.9151e+01     16  TR      1.5591e+01   1.3483e+01   2.0000e-03
   24  00:00:04   2.9120e+01     17          1.5591e+01   1.3450e+01   2.0000e-03
   26  00:00:04   2.9069e+01     18  PS      1.5591e+01   1.3395e+01   2.0000e-03
   26  00:00:04   2.9055e+01     19          1.5590e+01   1.3380e+01   2.0000e-03
   28  00:00:04   2.8990e+01     20          1.5590e+01   1.3309e+01   2.0000e-03
   30  00:00:04   2.8925e+01     21          1.5590e+01   1.3238e+01   2.0000e-03
   32  00:00:05   2.8860e+01     22          1.5590e+01   1.3168e+01   2.0000e-03
   34  00:00:05   2.8796e+01     23          1.5590e+01   1.3097e+01   2.0000e-03
   36  00:00:05   2.8731e+01     24          1.5589e+01   1.3026e+01   2.0000e-03
   38  00:00:05   2.8667e+01     25          1.5589e+01   1.2956e+01   2.0000e-03
   39  00:00:05   2.8649e+01     26  PS      1.5589e+01   1.2936e+01   2.0000e-03
   40  00:00:05   2.8603e+01     27          1.5589e+01   1.2885e+01   2.0000e-03
   42  00:00:05   2.8539e+01     28          1.5589e+01   1.2815e+01   2.0000e-03
   44  00:00:05   2.8475e+01     29          1.5588e+01   1.2744e+01   2.0000e-03
   46  00:00:05   2.8412e+01     30          1.5588e+01   1.2673e+01   2.0000e-03
   48  00:00:06   2.8349e+01     31          1.5588e+01   1.2603e+01   2.0000e-03
   50  00:00:06   2.8286e+01     32          1.5588e+01   1.2532e+01   2.0000e-03
   52  00:00:06   2.8223e+01     33          1.5587e+01   1.2461e+01   2.0000e-03
   54  00:00:06   2.8160e+01     34          1.5587e+01   1.2391e+01   2.0000e-03
   56  00:00:06   2.8098e+01     35          1.5587e+01   1.2320e+01   2.0000e-03
   58  00:00:06   2.8036e+01     36          1.5587e+01   1.2250e+01   2.0000e-03
   60  00:00:07   2.7975e+01     37          1.5587e+01   1.2180e+01   2.0000e-03
   62  00:00:07   2.7971e+01     38          1.5587e+01   1.2175e+01   2.0000e-03
   64  00:00:07   2.7970e+01     39          1.5587e+01   1.2173e+01   2.0000e-03
   66  00:00:07   2.7969e+01     40  FP      1.5587e+01   1.2173e+01   2.0000e-03
   66  00:00:07   2.7969e+01     41          1.5587e+01   1.2173e+01   2.0000e-03
   67  00:00:08   2.7969e+01     42  BP      1.5587e+01   1.2173e+01   2.0000e-03
   68  00:00:08   2.7970e+01     43          1.5587e+01   1.2174e+01   2.0000e-03
   70  00:00:08   2.7971e+01     44  EP      1.5587e+01   1.2175e+01   2.0000e-03

Constructing torus in reduced dynamical system

Interpolation at (omega,epsilon) = (1.559009e+01,2.000000e-03)
Interpolation at (omega,epsilon) = (1.559010e+01,2.000000e-03)
Interpolation at (omega,epsilon) = (1.559011e+01,2.000000e-03)
.
.
.
Illustration of the construction of torus in reduced dynamical system
Visualization of torus at (omega,epsilon)=(1.559006e+01,2.000000e-03)

FRCs from ='po2-40-7c.po': generating torus in physical domain.
the forcing frequency 1.5590e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
.
.
.

Continuation of Torus Bifurcations

SSM_po2TR: continuation of TR bifurcation periodic orbits
Continuation of quasi-periodic Hopf bifurcation of two-dimensional invairant
tori
bd    = coco_bd_read([po2id,'.po']);
TRlab = coco_bd_labs(bd,'TR');
assert(~isempty(TRlab), 'No TR periodic orbits are found');
set(S.contOptions, 'h_max',1, 'bi_direct', true, 'NAdapt', 0);              % continuation setting
TRid = ['TR-',num2str(nElements),'-',num2str(order),'c'];
S.SSM_po2TR(TRid,po2id,TRlab,{freqRange,epsRange},[outdof; outdof+n]);
 Run='TR-40-7c.po': Continue TR periodic orbits from label 16 of run po2-40-7c.

    STEP   DAMPING               NORMS              COMPUTATION TIMES
  IT SIT     GAMMA     ||d||     ||f||     ||U||   F(x)  DF(x)  SOLVE
   0                          3.25e-07  3.05e+01    0.0    0.0    0.0

 STEP      TIME        ||U||  LABEL  TYPE            om          eps    po.period
    0  00:00:00   3.0538e+01      1  EP      1.5591e+01   2.0000e-03   1.3483e+01
    2  00:00:00   3.0687e+01      2          1.5589e+01   1.9533e-03   1.3676e+01
    4  00:00:01   3.1227e+01      3          1.5585e+01   1.7994e-03   1.4366e+01
    6  00:00:02   3.1978e+01      4          1.5580e+01   1.6193e-03   1.5297e+01
    8  00:00:04   3.2513e+01      5          1.5577e+01   1.5084e-03   1.5956e+01
   10  00:00:04   3.2712e+01      6          1.5576e+01   1.4692e-03   1.6206e+01
   12  00:00:06   3.2781e+01      7          1.5576e+01   1.4557e-03   1.6295e+01
   14  00:00:07   3.2835e+01      8          1.5576e+01   1.4448e-03   1.6368e+01
   16  00:00:09   3.2840e+01      9          1.5575e+01   1.4438e-03   1.6374e+01
   18  00:00:11   3.2842e+01     10          1.5575e+01   1.4434e-03   1.6377e+01
   20  00:00:12   3.2844e+01     11          1.5575e+01   1.4428e-03   1.6381e+01
   22  00:00:13   3.2845e+01     12          1.5575e+01   1.4426e-03   1.6383e+01
   24  00:00:14   3.2847e+01     13          1.5575e+01   1.4424e-03   1.6384e+01
   26  00:00:14   3.2848e+01     14          1.5575e+01   1.4420e-03   1.6387e+01
   28  00:00:16   3.2850e+01     15          1.5575e+01   1.4417e-03   1.6388e+01
   30  00:00:16   3.2851e+01     16          1.5575e+01   1.4414e-03   1.6391e+01
   32  00:00:17   3.2854e+01     17          1.5575e+01   1.4407e-03   1.6395e+01
   34  00:00:19   3.2859e+01     18          1.5575e+01   1.4397e-03   1.6402e+01
   36  00:00:20   3.2862e+01     19          1.5575e+01   1.4392e-03   1.6405e+01
   38  00:00:21   3.2864e+01     20          1.5575e+01   1.4387e-03   1.6408e+01
   40  00:00:22   3.2868e+01     21          1.5575e+01   1.4379e-03   1.6414e+01
   42  00:00:23   3.2870e+01     22          1.5575e+01   1.4374e-03   1.6417e+01
   44  00:00:24   3.2873e+01     23          1.5575e+01   1.4367e-03   1.6422e+01
   46  00:00:25   3.2876e+01     24          1.5575e+01   1.4361e-03   1.6426e+01
   48  00:00:27   3.2877e+01     25          1.5575e+01   1.4359e-03   1.6428e+01
   50  00:00:27   3.2879e+01     26          1.5575e+01   1.4355e-03   1.6430e+01
   52  00:00:28   3.2880e+01     27          1.5575e+01   1.4352e-03   1.6432e+01
   54  00:00:29   3.2883e+01     28          1.5575e+01   1.4347e-03   1.6435e+01
   56  00:00:29   3.2889e+01     29          1.5575e+01   1.4334e-03   1.6445e+01
   58  00:00:31   3.2890e+01     30          1.5575e+01   1.4331e-03   1.6447e+01
   60  00:00:32   3.2892e+01     31          1.5575e+01   1.4327e-03   1.6449e+01
   62  00:00:33   3.2894e+01     32          1.5575e+01   1.4322e-03   1.6453e+01
   64  00:00:34   3.2895e+01     33          1.5575e+01   1.4319e-03   1.6455e+01
   66  00:00:35   3.2896e+01     34          1.5575e+01   1.4316e-03   1.6456e+01
   68  00:00:36   3.2898e+01     35          1.5575e+01   1.4314e-03   1.6458e+01
   70  00:00:37   3.2899e+01     36  EP      1.5575e+01   1.4311e-03   1.6460e+01

 STEP      TIME        ||U||  LABEL  TYPE            om          eps    po.period
    0  00:00:37   3.0538e+01     37  EP      1.5591e+01   2.0000e-03   1.3483e+01
    2  00:00:38   3.0439e+01     38          1.5592e+01   2.0324e-03   1.3354e+01
    4  00:00:38   3.0307e+01     39          1.5593e+01   2.0774e-03   1.3179e+01
    6  00:00:39   2.9836e+01     40          1.5597e+01   2.2542e-03   1.2544e+01
    8  00:00:40   2.8879e+01     41          1.5609e+01   2.7208e-03   1.1186e+01
   10  00:00:41   2.8311e+01     42          1.5618e+01   3.0970e-03   1.0326e+01
   12  00:00:42   2.7707e+01     43          1.5630e+01   3.6162e-03   9.3710e+00
   14  00:00:42   2.6858e+01     44          1.5652e+01   4.6459e-03   7.9764e+00
   16  00:00:43   2.6233e+01     45          1.5674e+01   5.7115e-03   6.9515e+00
   18  00:00:44   2.5731e+01     46          1.5697e+01   6.8408e-03   6.1454e+00
   20  00:00:44   2.5257e+01     47          1.5724e+01   8.2929e-03   5.3803e+00
   22  00:00:45   2.4872e+01     48  EP      1.5754e+01   1.0000e-02   4.7271e+00

Constructing torus in reduced dynamical system
 
Interpolation at (omega,epsilon) = (1.557513e+01,1.431095e-03)
Interpolation at (omega,epsilon) = (1.557514e+01,1.431408e-03)
Interpolation at (omega,epsilon) = (1.557515e+01,1.431643e-03)
Interpolation at (omega,epsilon) = (1.557516e+01,1.431905e-03)
.
.
.
 
Illustration of the construction of torus in reduced dynamical system
Visualization of torus at (omega,epsilon)=(1.575373e+01,1.000000e-02)

FRCs from ='TR-40-7c.po': generating torus in physical domain.

the forcing frequency 1.5575e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5576e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5577e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
the forcing frequency 1.5580e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01
.
.
.

SSM_TR2tor: continuation of tori from TR point Continuation of three-dimensional invariant tori

TRlab = 1; %
set(S.contOptions, 'h_max',100,'PtMX',50,'bi_direct',false,'NSV', 5);              % continuation setting
set(S.FRCOptions,"torNumSegs",15); %2*15+1=31 segments
torid = ['tor-',num2str(nElements),'-',num2str(order),'c'];
starttor = tic;
S.SSM_TR2tor(torid,TRid,TRlab,'freq',freqRange,[outdof; outdof+n],'saveICs');
timings.torFRC = toc(starttor);
 Run='tor-40-7c.tor': Continue tori born from TR point with label 1 of run TR-40-7c.

    STEP   DAMPING               NORMS              COMPUTATION TIMES
  IT SIT     GAMMA     ||d||     ||f||     ||U||   F(x)  DF(x)  SOLVE
   0                          3.84e-06  1.16e+02    0.0    0.0    0.0
   1   1  1.00e+00  2.11e-05  2.17e-10  1.16e+02    0.1    0.2    0.1
   2   1  1.00e+00  1.82e-05  8.24e-11  1.16e+02    0.1    0.5    0.1
   3   1  1.00e+00  1.19e-08  2.79e-15  1.16e+02    0.1    0.7    0.1

 STEP      TIME        ||U||  LABEL  TYPE            om       varrho          om1          om2          eps
    0  00:00:02   1.1586e+02      1  EP      1.5591e+01   5.0343e-03   2.3459e-03   4.6599e-01   2.0000e-03
    2  00:00:19   1.1586e+02      2  BP      1.5591e+01   5.0337e-03   2.3457e-03   4.6599e-01   2.0000e-03
    5  00:00:24   1.1586e+02      3          1.5591e+01   5.0252e-03   2.3417e-03   4.6599e-01   2.0000e-03
   10  00:00:33   1.1586e+02      4          1.5591e+01   4.9948e-03   2.3275e-03   4.6599e-01   2.0000e-03
   15  00:00:42   1.1586e+02      5          1.5591e+01   4.9435e-03   2.3036e-03   4.6598e-01   2.0000e-03
   20  00:00:53   1.1586e+02      6          1.5591e+01   4.8695e-03   2.2690e-03   4.6597e-01   2.0000e-03
   25  00:01:03   1.1586e+02      7          1.5591e+01   4.7748e-03   2.2248e-03   4.6594e-01   2.0000e-03
   30  00:01:15   1.1586e+02      8          1.5591e+01   4.6759e-03   2.1787e-03   4.6594e-01   2.0000e-03
   35  00:01:24   1.1587e+02      9          1.5591e+01   4.5589e-03   2.1240e-03   4.6590e-01   2.0000e-03
   40  00:01:36   1.1587e+02     10          1.5591e+01   4.4384e-03   2.0677e-03   4.6588e-01   2.0000e-03
   45  00:01:47   1.1587e+02     11          1.5591e+01   4.3157e-03   2.0105e-03   4.6585e-01   2.0000e-03
   50  00:02:02   1.1587e+02     12  EP      1.5591e+01   4.2020e-03   1.9573e-03   4.6581e-01   2.0000e-03
 
Constructing 3D torus in reduced dynamical system
 
Interpolation at frequency 1.559067e+01
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FRCs from ='tor-40-7c.tor': generating torus in physical domain.
the forcing frequency 1.5591e+01 is nearly resonant with the eigenvalue -1.0306e-03 + i1.5603e+01