1. Training Manual 001419 15 Aug 2000 3.4-1 Mode Superposition method allows non- proportional damping Block Lanczos solver enhancements Full harmonic analysis allows prestress effects 3.4 Dynamics Enhancements

2. Training Manual 001419 15 Aug 2000 3.4-2 Non-proportional damping available with mode superposition method at 5.7 –Modal analysis carried out using Q-R damped eigensolver –Allows all types of damping including element damping –Extremely fast compared to full method Dynamics Enhancements Q-R Damp & Mode Superposition Alpha damping valid Only applicable in a full or reduced harmonic Beta damping valid Material damping valid Element damping valid at 5.7 Frequency dependent damping valid

3. Training Manual 001419 15 Aug 2000 3.4-3 Applications Models where a “spring-damper” component needs to be represented by a single stiffness and damping constant. For example: –components of an automobile suspension system –dashpot mechanism on a door –simplified bearings on a rotor shaft –dampers used in a nuclear piping assembly Dynamics Enhancements … Q-R Damp & Mode Superposition

4. Training Manual 001419 15 Aug 2000 3.4-4 Procedure Modal analysis –MODOPT, qrdamp –Define damping* ALPHAD; BETAD; MP,DAMP (as before) New: element damping is also allowed, via COMBIN7, COMBIN14, COMBIN37, COMBIN40, CONT178 etc. Mode superposition –Transient analysis: TRNOPT,msup –Harmonic analysis: HROPT,msup *All damping must be specified in the modal analysis step Dynamics Enhancements … Q-R Damp & Mode Superposition

5. Training Manual 001419 15 Aug 2000 3.4-5 Limitations: –Damping specified during mode superposition is ignored. –QR damping does not support DMPRAT and MDAMP. –Gap conditions (GP) are not supported. Dynamics Enhancements … Q-R Damp & Mode Superposition

6. Training Manual 001419 15 Aug 2000 3.4-6 Elements: SOLID92 and COMBIN40 DOFs: 5531 Damping: Rayleigh, material, and element FY = 200 FZ = 1000 COMBIN40 SOLID92’s Dynamics Enhancements … Q-R Damp & Mode Superposition Benchmark Results

7. Training Manual 001419 15 Aug 2000 3.4-7 Dynamics Enhancements … Q-R Damp & Mode Superposition

8. Training Manual 001419 15 Aug 2000 3.4-8 Dynamics Enhancements Block Lanczos Enhancements Improved memory management –Automatic supplemental memory allocation –Intelligent choice of workspace –Minimum memory mode –Example: 1.4 million DOF problem, 10 modes, Compaq Alpha platform (1 cpu) –Required only 870 MB (-m 870) of memory. (5.6 required -m 2580) –8093 cpu sec, 11723 wall-clock sec