| 1372 | |
| 1373 | |
| 1374 | void Inerter::addPDeltaStiff(Matrix &kLocal, const Vector &qBasic) |
| 1375 | { |
| 1376 | int dirID; |
| 1377 | double N = 0.0; |
| 1378 | |
| 1379 | // get axial force |
| 1380 | for (int i=0; i<numDIR; i++) { |
| 1381 | if (dir(i) == 0) |
| 1382 | N = qBasic(i); |
| 1383 | } |
| 1384 | |
| 1385 | if (N != 0.0) { |
| 1386 | for (int i=0; i<numDIR; i++) { |
| 1387 | dirID = dir(i); // direction 0 to 5; |
| 1388 | |
| 1389 | // switch on dimensionality of element |
| 1390 | switch (elemType) { |
| 1391 | case D2N4: |
| 1392 | if (dirID == 1) { |
| 1393 | double NoverL = N/L; |
| 1394 | NoverL *= 1.0-Mratio(2)-Mratio(3); |
| 1395 | kLocal(1,1) += NoverL; |
| 1396 | kLocal(1,3) -= NoverL; |
| 1397 | kLocal(3,1) -= NoverL; |
| 1398 | kLocal(3,3) += NoverL; |
| 1399 | } |
| 1400 | break; |
| 1401 | case D2N6: |
| 1402 | if (dirID == 1) { |
| 1403 | double NoverL = N/L; |
| 1404 | NoverL *= 1.0-Mratio(2)-Mratio(3); |
| 1405 | kLocal(1,1) += NoverL; |
| 1406 | kLocal(1,4) -= NoverL; |
| 1407 | kLocal(4,1) -= NoverL; |
| 1408 | kLocal(4,4) += NoverL; |
| 1409 | } |
| 1410 | else if (dirID == 2) { |
| 1411 | kLocal(2,1) -= Mratio(2)*N; |
| 1412 | kLocal(2,4) += Mratio(2)*N; |
| 1413 | kLocal(5,1) -= Mratio(3)*N; |
| 1414 | kLocal(5,4) += Mratio(3)*N; |
| 1415 | } |
| 1416 | break; |
| 1417 | case D3N6: |
| 1418 | if (dirID == 1) { |
| 1419 | double NoverL = N/L; |
| 1420 | NoverL *= 1.0-Mratio(2)-Mratio(3); |
| 1421 | kLocal(1,1) += NoverL; |
| 1422 | kLocal(1,4) -= NoverL; |
| 1423 | kLocal(4,1) -= NoverL; |
| 1424 | kLocal(4,4) += NoverL; |
| 1425 | } |
| 1426 | else if (dirID == 2) { |
| 1427 | double NoverL = N/L; |
| 1428 | NoverL *= 1.0-Mratio(0)-Mratio(1); |
| 1429 | kLocal(2,2) += NoverL; |
| 1430 | kLocal(2,5) -= NoverL; |
| 1431 | kLocal(5,2) -= NoverL; |