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Use of Residual Vectors in SuperElement creation
Hello, after reading this thread Link I have a question about the use of residual vectors in superelements generation. Can the use of residual vectors replace the need of including too many high frequency modes during the condensation run? What I mean is: let's assume I have a structure which... -
Solving ODE with Coulomb friction
Hi, I would like to solve an ODE rapresenting a SDOF spring-mass-damper system with Coulomb friction. The system is subjected to base acceleration ÿ, therefore the equation of motion is the following mü + cú + ku = -mÿ - µdN sign(ú) where µd is the dynamic friction coefficient, N the normal...- Rhei
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- Replies: 0
- Forum: MathWorks, Inc.: MATLAB
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Logarithmic sine sweep: how to compute cycles?
Hi, I am running a transient simulation in Nastran. The structure undergoes a sine-sweep base acceleration and I need to compute the number of cycles the structure will se during the whole simulation. How do I do that knowing the sweep rate (R [oct/min]), the total duraton (T [s]) and the...- Rhei
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- Replies: 2
- Forum: Spacecraft engineering
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Link friction to damping
Hi, is it possible to retrieve a relationship between friction and damping? I run a non-linear transient solution (Nastran SOL 129) of a model in which I modelled the friction effect using CGAP elements. What I see is that, because of the dissipation, the response at resonance has a lower...- Rhei
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- Replies: 0
- Forum: Finite Element Analysis (FEA) engineering
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SOL 129 set up
Hi, I am running a non-linear transient analysis using SOL 129 and I was wondering, how can I be reasonably sure I have chosen the right DT value in the TSPENL card? My excitation is a sine-sweep in the range 5-40 Hz and I am now using a DT = 5.E-4. I would say this is enough since it means I...
