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How to compare dynamic systems of different degree of abstraction?

I'm modelling a vehicle as a multibody system in Matlab/Simulink. My goals are: Have a realistic simulation model so I don't have to do prototype measurements all the time. Solve specific parameter estimation tasks and apply driver assistance…
Marius Oei
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Which one is preferable? Multiple layers of reinforcements or one layer of reinforcement?

For RC beams, which one is preferable to be designed for construction? Is it multiple layer of reinforcements or one single layer? and why? Eg. If the beam required 3T20, is it preferable one layer of 3T20 or multiple layers: 2T16+3t16? Thanks
L4Legit
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Is the viscosity solution of Hamilton-Jacobi equation of practical use in optimal control?

My understanding is, given an optimal control problem, one can show that the optimal cost satisfies a Hamilton-Jacobi PDE and use dynamic programming to figure out the optimal control. However, sometimes this PDE has no strong solution, and the deep…
Isley
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Minimal realization of a MISO system

Given the following system: $$\dot{x} = \begin{bmatrix}1 & 1 & 0 \\ 0 & 1 & 0 \\ 0 & 1 & 1 \end{bmatrix}x + \begin{bmatrix}0 & 1 \\ 1 & 0 \\ 0 & 1 \end{bmatrix} u$$ $$y = \begin{bmatrix}1 & 1 & 1 \end{bmatrix} x$$ I need to find the minimal…
Unnamed
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Quantifying and measuring friction under extreme conditions

I want to quantify friction between a bullet and barrel to test different friction-proofing coatings and treatments. Is there a controlled test I could do at low speeds in a lab between samples of treated copper and steel that would be theoretically…
feetwet
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Reason of Using exactly 5 Wheel Studs per Wheel

So today when I was taking a taxi and looked at the vehicles, I observed that the majority of the light vehicles (i.e. 16-person minibus/ 4-6 person cars) use 5 (or less frequently, 6) wheels studs for each wheel. Intuitively, 6 evenly distributed…
Mythomorphic
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Why does flow seperation cause low pressure zone?

I know that flow seperation occurs when the fluid adjacent to a body deviates from the contours of the body . This occurs because the pressure increases in the direction of flow and velocity decreases until it reaches zero , and then , the flow…
Eman.suradi
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How to reverse the direction of rotational movement on the same axis?

I want to make a "gearbox" that will transform input rotational movement to an output rotational movement with the same speed but in the different direction (clockwise / counterclockwise) on the same axis. How can this be done?
SIMEL
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What is the difference between FEA and CFD?

Many of us think FEA is used for structural problems and CFD is used for fluid dynamics problems. But I have read that the above statement is wrong. So please explain the exact usage of those two.Also please give the basic difference between them.
Pradeep Chada
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How much does the elasticity (Young's Modulus) of concrete and asphalt change with ambient temperature?

I'm assuming here that all materials will have a change in elasticity due to thermal expansion/contraction and a resultant reduction/increase in the strength of the bonds of the atoms leading to a varying young's modulus. But how significant is it…
Noobie
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Why use two tower cranes on one construction site?

I am fascinated by construction. My university is building a new facility, and they are using 2 tower cranes in the construction. Why would a contractor choose to use 2 cranes on one construction project? Is it simply a matter of saving time by…
waterloo
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How is it possible electromagnets keep a heavy maglev train levitating without forcing anything metallic to be flinged away?

I always wondered how it is possible to have electromagnets so strong that they keep a heavy maglev-train levitating without forcing anything metallic to be flinged away or to be pressed against the ceiling of the vehicle-cabin? And how come a…
t0bias
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Poisson ratio boundary condition

Let's say I have a large isotropic body in uniaxial tension, onto which a small rectangular piece of film is applied. Think of a strain gage on a big body, but the 'strain gage' is one single continuous isotropic layer. Let x- and y-direction be on…
JLo
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How to generate NACA 5 digit airfoil coordinates?

I want to generate NACA 63824 airfoil coordinates to use them in my bachelor thesis. I tried airfoil tools and java foil. But I can't generate 638xx series. Can you recommend me a program or a code that generates these airfoil coordinates?
papabiceps
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Why is high stagnation pressure important for propulsion?

In my propulsion notes I always see mention of the importance of minimizing stagnation pressure loss across the inlet shock of a ramjet/turbojet/turbofan. Could anyone explain further why this is the case, possibly with equations to explain certain…
InquisitiveInquirer
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