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Hello my friends!! I have used LQR control strategy to control a 3 layer sandwich beam with one piezoelectric patch . I have plotted voltage response applied to actuator for 3 different thicknesses. My voltage responses have almost same amplitude with different trends. Does anyone know why this...

Hi dear friends! I have recently learnt eigenvalue problems and I'm a beginner! I calculated the eigenvalue of a system and the result was EV=12+2i . I have figured out that "12" is frequency and its unit is " rad/s " and "2" is damping parameter but I don't know what its unit is! Can anyone...

Hi all!! Does anyone know about the Piston theory ?! I want to know what the " First Order Quasi Steady Piston Theory " means ?! Especially, What does " Quasi Steady " refer to ?!

Actually, that wasn't my idea to design a AL/C-Epoxy/AL !! Having a composite course and its assignment, force me to that!! I derived the equation of motion of this beam ( Vibration analysis !!) and now I want to validate or my results with a one-layer AL beam!! How does it possible?!

Hi dear friends, I have modeled and derived equations for a 3 layer sandwich panel ( upper & Lower layers are Aluminium and the core is Carbon/ Epoxy ). I want to validate my results with a one layer panel which is made up of Aluminium. Is it correct to replace Aluminium properties with...

Hello everyone! I am trying to calculate the transient 1D heat equation in mathematica. I am trying to use BTCS method for solving it! I have finish my code, but it works only in t=0 and for the rests, it gives me an error ! Is anyone familiar with Mathematica software ? I need your help...

Hi guys! I am a beginner in Control field !! I have a system which is observable but not controllable! What does it mean ?! It means that I can not control my sytem with any of controlling method ?!

In fact, I have a uniform beam with piezo actuator/sensor film and I want to control it based on LQR controller method. For gaining accurate results and convergence, I have to use at least 4 mode shapes in my numerical method. As a result, as I increase my mode shape in my code, the number of...

Hi guys!! Does anyone know anything about LQR method? I have a problem in my code to gain a correct k-gains!!

I want to plot the displacements vs. time!! I do not know how to plot it in NASTRAN !! I tried OUTPUT ( XYPLOT ), but it didn't work at all!! Does anyone know how to do that?![sad]

I want to plot the displacements vs. time!! I do not know how to plot it in NASTRAN !! I tried OUTPUT ( XYPLOT ), but it didn't work at all!! Does anyone know how to do that?![sad]

Dear everyone, I use OUTPUT (XYOUT) to plot the data. The format of output file is .plt . Does anyone know how I can change the output file format from .plt to something else ?! Thank you !![glasses]

Dear everyone, I use OUTPUT (XYOUT) to plot the data. The format of output file is .plt . Does anyone know how I can change the output file format from .plt to something else ?! Thank you !![glasses]

Thank you anyway dear almpunk !! [wink]

I got it dear almpunk !! Thank you so much !! [glasses] You know what is going on !?! I want to model a SHELL as a beam and then use it in PATRAN to calculate FLUTTER analysis. I modeled the shell and validate the 10 first Natural Frequencies with another code in an other software. but when I...

Thank you almpunk !!It was really useful. [glasses] Is it necessary to use MPC in my shell properties to make it a real beam ? For example some mode shapes[ i.e, torsional mode shapes] appear in shell properties which never happen in beam properties. I tried some MPCs, but I still had torsional...

Hi everyone!! I want to model a beam structure using shell properties in PATRAN. I want to know if it is possible to do that. If yes, how could I do that???!! Please someone help me! Thank you in advance![glasses]

Hi everyone!! I want to model a beam structure using shell properties in PATRAN. I want to know if it is possible to do that. If yes, how could I do that???!! Please someone help me! Thank you in advance![glasses]

Hi everyone!! I want to model a beam structure using shell properties in PATRAN. I want to know if it is possible to do that. If yes, how could I do that???!! Please someone help me! Thank you in advance![glasses]