Error in eigen analysis?

[rafetsisman]

Hi,

I have a 3D model of a 3x3 bay 3 storey building, and I am trying to determine its first natural period by using OpenSees. I have modeled beams and columns with mass density so I did not introduced nodal masses with mass command. All beam sections are the same and 0.25x0.50 in meters, and all column sections are the same and 0.4x0.4 in meters. Elastic modulus and shear modlus are the same for all beam and column elements. Here is the error/warning I have encountered:

ArpackSolver::Maximum number of iteration reached.

Here is my script:

wipe
model basic -ndm 3 -ndf 6
node 111 0 0 0
node 121 5 0 0
node 131 10 0 0
node 141 15 0 0
node 112 0 0 -5
node 122 5 0 -5
node 132 10 0 -5
node 142 15 0 -5
node 113 0 0 -10
node 123 5 0 -10
node 133 10 0 -10
node 143 15 0 -10
node 114 0 0 -15
node 124 5 0 -15
node 134 10 0 -15
node 144 15 0 -15
node 211 0 3 0
node 221 5 3 0
node 231 10 3 0
node 241 15 3 0
node 212 0 3 -5
node 222 5 3 -5
node 232 10 3 -5
node 242 15 3 -5
node 213 0 3 -10
node 223 5 3 -10
node 233 10 3 -10
node 243 15 3 -10
node 214 0 3 -15
node 224 5 3 -15
node 234 10 3 -15
node 244 15 3 -15
node 311 0 6 0
node 321 5 6 0
node 331 10 6 0
node 341 15 6 0
node 312 0 6 -5
node 322 5 6 -5
node 332 10 6 -5
node 342 15 6 -5
node 313 0 6 -10
node 323 5 6 -10
node 333 10 6 -10
node 343 15 6 -10
node 314 0 6 -15
node 324 5 6 -15
node 334 10 6 -15
node 344 15 6 -15
node 411 0 9 0
node 421 5 9 0
node 431 10 9 0
node 441 15 9 0
node 412 0 9 -5
node 422 5 9 -5
node 432 10 9 -5
node 442 15 9 -5
node 413 0 9 -10
node 423 5 9 -10
node 433 10 9 -10
node 443 15 9 -10
node 414 0 9 -15
node 424 5 9 -15
node 434 10 9 -15
node 444 15 9 -15
geomTransf Linear 1 0 1 0
geomTransf Linear 2 0 0 -1
element elasticBeamColumn 1 111 121 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 2 121 131 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 3 131 141 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 4 112 122 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 5 122 132 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 6 132 142 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 7 113 123 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 8 123 133 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 9 133 143 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 10 114 124 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 11 124 134 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 12 134 144 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 13 111 112 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 14 112 113 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 15 113 114 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 16 121 122 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 17 122 123 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 18 123 124 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 19 131 132 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 20 132 133 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 21 133 134 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 22 141 142 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 23 142 143 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 24 143 144 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 25 211 221 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 26 221 231 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 27 231 241 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 28 212 222 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 29 222 232 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 30 232 242 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 31 213 223 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 32 223 233 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 33 233 243 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 34 214 224 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 35 224 234 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 36 234 244 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 37 211 212 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 38 212 213 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 39 213 214 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 40 221 222 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 41 222 223 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 42 223 224 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 43 231 232 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 44 232 233 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 45 233 234 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 46 241 242 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 47 242 243 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 48 243 244 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 49 311 321 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 50 321 331 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 51 331 341 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 52 312 322 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 53 322 332 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 54 332 342 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 55 313 323 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 56 323 333 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 57 333 343 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 58 314 324 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 59 324 334 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 60 334 344 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 61 311 312 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 62 312 313 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 63 313 314 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 64 321 322 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 65 322 323 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 66 323 324 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 67 331 332 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 68 332 333 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 69 333 334 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 70 341 342 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 71 342 343 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 72 343 344 1.250000e-01 30000000 12500000 3.255208e-03 2.604167e-03 6.510417e-04 1 -mass 3.125000e-01
element elasticBeamColumn 73 111 211 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 74 112 212 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 75 113 213 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 76 114 214 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 77 121 221 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 78 122 222 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 79 123 223 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 80 124 224 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 81 131 231 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 82 132 232 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 83 133 233 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 84 134 234 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 85 141 241 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 86 142 242 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 87 143 243 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 88 144 244 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 89 211 311 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 90 212 312 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 91 213 313 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 92 214 314 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 93 221 321 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 94 222 322 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 95 223 323 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 96 224 324 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 97 231 331 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 98 232 332 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 99 233 333 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 100 234 334 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 101 241 341 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 102 242 342 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 103 243 343 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 104 244 344 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 105 311 411 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 106 312 412 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 107 313 413 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 108 314 414 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 109 321 421 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 110 322 422 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 111 323 423 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 112 324 424 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 113 331 431 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 114 332 432 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 115 333 433 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 116 334 434 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 117 341 441 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 118 342 442 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 119 343 443 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
element elasticBeamColumn 120 344 444 1.600000e-01 30000000 12500000 4.266667e-03 2.133333e-03 2.133333e-03 2 -mass 4.000000e-01
fix 111 1 1 1 1 1 1
fix 121 1 1 1 1 1 1
fix 131 1 1 1 1 1 1
fix 141 1 1 1 1 1 1
fix 112 1 1 1 1 1 1
fix 122 1 1 1 1 1 1
fix 132 1 1 1 1 1 1
fix 142 1 1 1 1 1 1
fix 113 1 1 1 1 1 1
fix 123 1 1 1 1 1 1
fix 133 1 1 1 1 1 1
fix 143 1 1 1 1 1 1
fix 114 1 1 1 1 1 1
fix 124 1 1 1 1 1 1
fix 134 1 1 1 1 1 1
fix 144 1 1 1 1 1 1
rigidDiaphragm 2 211 221 231 241 212 222 232 242 213 223 233 243 214 224 234 244
rigidDiaphragm 2 311 321 331 341 312 322 332 342 313 323 333 343 314 324 334 344
rigidDiaphragm 2 411 421 431 441 412 422 432 442 413 423 433 443 414 424 434 444
for { set k 1 } { $k <= 1 } { incr k } {
recorder Node -file [format "mode%i.out" $k] -node 111 121 131 141 112 122 132 142 113 123 133 143 114 124 134 144 211 221 231 241 212 222 232 242 213 223 233 243 214 224 234 244 311 321 331 341 312 322 332 342 313 323 333 343 314 324 334 344 411 421 431 441 412 422 432 442 413 423 433 443 414 424 434 444 -dof 1 2 3 "eigen $k"
}
set lambda [eigen 1 ]
set omega {}
set f {}
set T {}
set pi 3.141593
foreach lam $lambda {
lappend omega [expr sqrt($lam)]
lappend f [expr sqrt($lam)/(2*$pi)]
lappend T [expr (2*$pi)/sqrt($lam)]
}
set period "Periods.txt"
set Periods [open $period "w"]
foreach t $T {
puts $Periods " $t"
}
close $Periods
record

Any comments will be highly appreciated.

Rafet

[rafal]

Why don't you use 'Search' tool? You would find the answer quicker.

[rafetsisman]

Thank you rafal, actually I was not aware of that tool.

I have fixed the problem, but another issue emerged when tried to introduce SSI by using truss elements as springs. Here is the recent warning;

WARNING BandGenLinLapackSolver::solve() -LAPACK routine returned 28

I have modeled truss elements in 3 directions for each node at y=0 (ground level).

Any help?

[fmk]

you probably do not have enough constraints .. when you added the truss elements at the ground did you constrain ALL the ground nodes rotationally?

[rafetsisman]

At first I did not fix rotational DOFs, but now I have fixed that nodes in both translation and rotation. Now it is working, but I wonder is it appropriate to use truss elements and fix them rotationally?

[fmk]

i was simply pointing out why if you suddenly add trusses at the base of the model to do your SSI, your model was going to fail unless you constrained the rotational dof at the fixed node .. the modeling choices you make are up to you, though most doing SSI just use springs/trusses on the translational dof .. you could of course add springs for the rotational dof if you wanted.

[rafetsisman]

Thank you Mr. McKenna