Recent content by swraman

Hi, Im trying to build a resonant circuit with a ~low frequency resonance (<1kHz). I am using a Gyrator (https://en.wikipedia.org/wiki/Gyrator#Application:_a_simulated_inductor) as the inductor. Im using: RL = 100ohm R = 27kohm C = 1uF I put another 1uF capacitor in front of Zin, to form a...

Good to hear. The "support type" (constraints or BCs) is very critical in FEA. When I was learning, my constraints were the cause of most of my mistakes. It helps to think of things in terms of nodes instead of physical shapes (that is, as a series of triangles instead of a circle).

Im not familiar with ANSYS, but are those arrows your BCs (the supports)? It looks like you have "BCs" at the centerpoints between the edge nodes...Is that the case? Also, are the BCs on the upper right hand side of the upper right half the same as the BCs on the lower left (asking because the...

Typically companies like LMS are small and you'd need to contact them directly. They should have application engineers who are themselves well versed in the software and its applications. They may ask you to pay for a service contract though.

Ah...Thats what I am looking for. Thanks. Only problem is this is to be used in a control loop, so time is of a concern.

I am dealing with a 3x4 complex matrix M that relates a vector d to another vetor c. That is: c = [M]*d d is 4x1 and c is 3x1. I want to introduce a new line (constraint) into M, say d(1) = d(2). However, I would like to only apply the constraint to the real or only the imaginary parts. Is...

That is what I was thinking, but lsim (and many of matlabs transfer function methods) only works for transfer functions with more poles than zeros.

Is there any way to then determine the input necessary for an arbitrary desired output, if the output is not some function easily described in the laplace domain? ie. when our desired output is some arbitrary time waveform, can we use the inverse transfer function P2/P1 to determine the...

Hello, I have a laplace domain system transfer function. I know I can use (say Matlab's lsim()) to simulate the output for any arbitrary input. Is there any way (numerically in Matlab or analytically) to determine the input necessary for a desired output time signal?

The largest forces would be at the inner circle, wouldn't they? An infinitesimal area at the inner circle has a mass of (m = rho * t * (r2-r1) * dTheta) that is trying to escape due to its inertial, with the radial force of (F = .5 * (wr)^2 * rho * t * dTheta * dr) By reasonable, I mean that...

So, I am watching this show about airline crashes and apparently, a A380 has gone down because the speed limiter on a spinning engine rotor broke, and the part spun so fast its ultimate yield strength was reached and the material shatterted. Thats got to be one really fast spinning rotor! But...

I just added eqn (2) to show how similar the Laplace transform is to the Fourier transform (which has a well defined Discrete cousin in the DFT). I know there's nothing new about it. The thinking was: If (4) is the discretized version of (3), why can we not generate another function that is a...

Hi, I have an idea which when tested looks like its clearly flawed. I am hoping someone can tell me where my procedure is flawed, or point me to some other theory that has already done something similar. The first two are the laplace transform. The third line is the Fourier Transform. The...

MIT and Berkeley also have lots of engineering lecture/courses for free online: http://ocw.mit.edu/index.htm http://webcast.berkeley.edu/

I am wondering why the FRF method does not produce accurate results. I am assuming that my original Laplace domain created in step 1 produces the exact result. 500Hz was randomly chosen as my nyquist frequency for this little experiment; it is well above the 10Hz resonance of my system. I had...