12 votes
Accepted

Which turbulence models are suitable for CFD analysis on a streamlined vehicle body?

The turbulence model can make a big difference in your simulation. There are many turbulence models around. It becomes a tough job to select one out of them. There is no perfect turbulence model. It ...
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  • 1,423
8 votes
Accepted

What filter is this?

It might be written that way because the transfer function of a second order system is written as: $$ h(s) = \frac{\omega_n^2}{s^2 + 2\zeta \omega_n s + \omega_n^2} $$ where $\zeta$ is the relative ...
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5 votes
Accepted

Where does weight mass conversion ratio '0.00259' come from in Nastran?

It's the inverse of the acceleration of gravity g in imperial units. $$ 1 g = 386.1 in/s^2 $$ $$ 1/g = 0.00259 s^2/in $$ You need that since: $$ weight = mass * g $$
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  • 176
5 votes
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What amplitude is used for a finite element modal analysis excitation?

The short answer is, there is no amplitude used. Even more important though, is the fact that the displacements and stresses shown in the results of a modal analysis cannot be used to say anything ...
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5 votes

What amplitude is used for a finite element modal analysis excitation?

The amplitudes of the modes from a vibration analysis are arbitrary. Often they are "mass-normalized" which is mathematically convenient for using them in a subsequent step in the analysis. There may ...
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  • 12.5k
5 votes

How to convert Joules(kinetic energy) plot chart into watts?

To convert a plot of J versus s to a plot of J/s vs s, take the derivative. Here is my quick-and-dirty answer after digitizing the data.
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4 votes
Accepted

How to simulate the contact between two distant parts in Ansys workbench?

Okay so I ended up having a play in ANSYS Mechanical Workbench. I did a mock up of your problem. Here's how I've been able to successfully model it. Note that a lot of my decisions are based on the ...
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  • 1,217
4 votes

Is there any aspect of an Explosion resulting from a nuclear weapon test that cannot be simulated using super computers?

The type of machine that runs the simulation (e.g. super computer, slide rule, pen and paper, etc.) is less important than the physical and mathematical models that describe the process being ...
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  • 2,989
4 votes

How much force can a pole in ground take before falling?

this is a typical engineering problem and has an equation approved by IBC numbered 18-1. $$d = 0.5 A{1 + [1 + (4.36h/A)]1/2}$$ The calculation process is I first calculate A =2.3* post load/(allowed ...
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  • 21.1k
3 votes
Accepted

Non-Clutch Vehicle Drivetrain - How Does it Work?

Conventional automatic transmissions have a torque converter which uses a viscous rather than a rigid coupling to connect input and output. This performs a similar function to a friction clutch but ...
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3 votes

Is there any aspect of an Explosion resulting from a nuclear weapon test that cannot be simulated using super computers?

The accuracy of a simulation depends more on how well your equations and assumptions model reality, than the resolution of the simulation (computing power, as Carlton has stated). More computing power ...
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  • 7,489
3 votes

How do I model a longitudinal tensile strain in a laminate composite using Abaqus software?

Without knowing more about your problem the first thing that you need to do is make sure that you are using the right geometry and elements. To use that representation you need to use: 2D geometry ...
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3 votes
Accepted

ANSYS Workbench/Mechanical: Automatically export chart?

There are several options for doing this: If there are only a few values to be saved per design point, you could use 'output parameters'. If there is a lot of data to be saved, the report generator ...
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  • 156
3 votes

How to implement a Monte Carlo Simulation for studying uncertainty in dynamic stiffness?

My advice would be to forget about the mathematical theory and start thinking about what the engineering means. It's hard to think of any situation where the stiffness of a sensibly designed structure ...
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  • 12.5k
3 votes

How to determine time taken for tyre to deflate using CFD analysis?

I don't think CFD is the right tool. You can use an orifice equation, say from ASME, to calculate flow rate from inner and outer pressure. This takes the form of: $$\dot{m}=\frac{EC_D}{\sqrt{1-\beta^4}...
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  • 451
2 votes
Accepted

How can I model or simulate motion caused by an internal vibrating motor?

@Narada is correct, but I their answer is a bit short on detail, so I will expand on it. Calculating Force First, you can calculate the force that the motor exerts on the containing object from the ...
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  • 1,167
2 votes

Which turbulence models are suitable for CFD analysis on a streamlined vehicle body?

I can't say that this will be the ideal answer, but it should get you started. As will be apparent, I not a true expert. The quality of these models will generally increase with their sophistication, ...
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  • 1,976
2 votes

SolidWorks circuit simulation?

CircuitWorks doesn't simulate the electronics; it just integrates between some common PCB design software formats and SolidWorks for mechanical information. For example, maximum component height, ...
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  • 318
2 votes

How can I save mass, inertia, joint location and part orientation data from any 3D-CAD program to a CAD file?

This sounds like the exact synopsis of my masters thesis. Theoretically a format that can contain this info exits. STEP could include this information, but since the exporter has some serious leeway ...
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  • 3,435
2 votes

Component-based simulation versus block-based simulation

Components have connections that can be either inputs or outputs, while blocks have defined inputs and defined outputs. With the components you can have bidirectional causality while if you want to ...
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  • 1,295
2 votes
Accepted

How much force can a pole in ground take before falling?

Depending on the kind of engineer you ask you will get many different options to approach this - your question is pretty open-ended. As a Geotechnical Engineer I'd say your pole can be looked at as a ...
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  • 36
2 votes

Automotive Radiator Simulation

Either your definition of "completely" is a bit unusual, or there's something wrong with those charts, because in those charts, 1.6 x the model does not completely match any of the six observations ...
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  • 3,701
2 votes

Simulation of motion, collision, friction and thermal expansion in 3D

This is a multi-physics analysis, there are some open source packages though i'm not familiar with them (OpenFOAM is open source CFD software, and COMSOL is example of an commercial multi-physics ...
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  • 632
2 votes
Accepted

LS DYNA Material Model 163, Modified Crushable Foam

While the yield stress is a well defined point in materials such as steel or other metals, that is not the case when we talk about foams. Here they are calling "yield stress" to the whole volumetric ...
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2 votes

How should the assignment to test software for a vehicle’s VCU be aproached?

I am not too familiar with the VCU, PV780, or PowerVision. Based on your description PV780 can be configured to be the Instrument Cluster Panel (ICP) for Engine Control Unit/Module (ECM) or ...
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2 votes

How can I validate the validity of a model of a dynamical system?

Verify your model against actual physical hardware. If you're sure of parts of the model, and unsure of others, then just verify the parts you're worried about. If the physical hardware is big and ...
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  • 2,228
2 votes
Accepted

Calculating final drive force from engine torque and tyre spin ratio

You need to convert the torque at the axle into force against the ground through the tire (Force = torque/radius). Then F=ma for the entire mass of the car (plus if you want to be precise the ...
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  • 4,820
2 votes
Accepted

Is a MSC Adams simulation with smaller steps always more reliable?

This is a common issue on all numerical methods (not just multibody problems), i.e. the tradeoff between the following three types of error: Round off error Discretization Truncation (sometimes the 2 ...
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  • 22.7k
2 votes

Simulation of RC circuit using Proteus

Try using a replacing a 9V VDC voltage source with a VAC voltage source. Pay attention to the frequency of the VAC voltage source. This should address the issue. With regard to determining the time ...
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2 votes

What meaning does the following sine wave have when it comes to amplitude?

It means that there is a positive offset of one. So your signal is $$ x(t) = 1 + 2 \cdot \sin(\omega t)$$ where: 1 is the offset 2 is the amplitude of your signal (not 4).
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  • 22.7k

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