Questions tagged [modeling]
Use this tag for questions about numerical or analytical modeling and simulation of engineered systems.
132
questions
-1
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0answers
9 views
How to calculate the thermodynamics properties of the LiBr/H2O solution?
When modelling an absorption heat pump cycle one would need to calculate the state properties of absorbent, absorber, and the mixture of these two; in order to find out the cycle properties. Is there ...
2
votes
1answer
43 views
Modelling a refrigeration cycle in Excel
Is it possible to model a heat pump cycle without using tools like EES, but using Excel? I am considering to use Refprop application as an add-in in Excel, and model a heat pump cycle. Another ...
1
vote
0answers
12 views
Visualization/Verification software for interacting parts e.g. Gears etc
Not sure if there is any software that would model the movements of physical parts, or if even they can move with the given configurations ( software engineer background, no idea the lingo used here )....
1
vote
1answer
40 views
How to calculate initial concentration of first-order reaction in CSTR?
(This question comes from a Chemical Engineering background, but basic Math and Programming knowledge is also required. I hope it still falls in the scope of engineering.stackexchange.com If not, ...
1
vote
1answer
17 views
Overextending and cutting a coil spring
This is related to my recent question
Can I weaken a coil spring consisting of spring steel?. The answer here could create an additional answer there, but I do not expect that. The difference to that ...
0
votes
1answer
34 views
Modelling Soil in a Scale Model
I'm building a scale model for a proposed construction project.
Is it possible to simulate foundations operating in soil in a scale model? What do people typically use?
0
votes
0answers
26 views
Can Flowmaster be used to model an entire pipe run?
I just started using the Flowmaster program (ver 08.11.01.03 if relevant) to model a series of stormwater pipes which are almost certainly in a pressure flow situation based on a first round analysis ...
1
vote
3answers
52 views
Why do we get singularities in a solutions while modelling a physical systems?
I wonder why do we get some times singularities (position to be infinity or velocity to be infinity) in the solutions while modelling a real system and in spite of taking all real parameter values of ...
0
votes
0answers
62 views
Help with Engineering Mathematics, Struggling to determine coefficients using methods detailed in this research paper
I am struggling with a curve fitting calculation below. the part I am stuck with is arguably the simplest part, which is determining the coefficients $\\K_3$ and $\\K_4$. It seems like it should be ...
0
votes
1answer
21 views
ElectroMagnetic Pulling Force fdropoff with distance
I am looking make a quick and dirty test ring using an off the shelf electromagnet. My force needs are small, less than a pound but I need to do so in a non contact manner. I know these magnets are ...
0
votes
0answers
14 views
The steps in photogrammetry pipeline
I am interested in photogrammetry and wanted to see if I had a good overview of the steps of the photogrammetry pipeline and can anyone help me expand on these steps, provide resources on how they are ...
0
votes
1answer
16 views
How can I validate the validity of a model of a dynamical system?
I derived a non linear differential equation system for a mechanical system. However I doubt the correctness of it.
So I compared the model's dynamics with a VREP simulation. I did this by
by Euler ...
0
votes
1answer
35 views
Is it possible to have open loop with same input term as the output?
For example, i have this differential equation:
$$\dot{y} = 1.8 + 0.58u \sqrt{y}$$
Is it possible to model this system in open loop?? My understanding is that since the term $y$ is in the output ...
1
vote
1answer
57 views
FEA: What is the difference between a spider of RBE2s and multiple SPCs
I am not sure what the difference is between using a spider of RBE2s. and multiple SPCs across a face. I've heard that the spider is the more accurate method as multiple SPCs make the model overly ...
1
vote
0answers
33 views
Distance travelled at articulation point of turning vehicle
Problem outline:
I'm trying to figure out the distance travelled at the articulation point of a turning vehicle with 4 driven wheels (each wheel houses a motor and can all rotate at different RPMs). ...
0
votes
0answers
28 views
Why would a SMD (spring mass damper) model of steel break down?
Under what conditions would steel be able to be modelled as a 3D SMD model, and under what conditions would the model break down?
1
vote
1answer
84 views
FEA: Newton-Raphson algorithm for Dirichlet BC non-linear static analysis
I have a standard non-linear static problem to solve with FEA. I am applying displacement boundary conditions only, no external force. The equation to solve look like these:
$K(u)u=R(u)$ Eq(1)
The ...
1
vote
0answers
16 views
Modeling of a Wireless Channel with known BER
I have to model through software a wireless (my choice: 3g,4g, 802.11...) channel with given Bit Error Rate. I'm searching some distributions, I'm reading tons of papers but I can't find how to ...
1
vote
1answer
20 views
Drucker-Prager Model Parameters, a Proper Choice
My task is to write a code from scratch for 3D elastoplasticity, namely a DP model (see for example DeSouza Neto, et al., 2008, Chapter 8) having yield surface
$$ f(\mathbf{\sigma},c) = \sqrt{J_2(\...
-1
votes
2answers
38 views
What is the engineering way to describe a factory / manufacturing plant system in a formel and mathematical way
I am interested in mathematically describing as well as formalising a manufacturing plant so that other people in the engineering field understand how the system works. I am not from the engineering ...
0
votes
0answers
22 views
Source for learning Functional derivative , Gateaux derivative
I have started doing research in optimal control theory. My area of research is PDE constrained optimization.
I am facing significant difficulty in deriving the Gateaux Derivative of functionals ...
0
votes
0answers
27 views
Developing a model of rate of cooling of steel tube in air
I am trying to develop an equation to determine the cooling rate of a steel tube in air. I'm using Fourier's Law, Stefan-Boltzman Law, Newton's Law as well as the specific heat capacity equation. The ...
0
votes
2answers
75 views
Is there any device that can capture a picture into 3D model?
I am currently wondering is there any way or device that can transform a picture into 3D model automatically?
or a machine learning thing to learn from picture (2D) into 3D model?
3
votes
1answer
218 views
Torsional rigidity D vs torsional rigidity factor k vs torsion constant J
I have a physics background so apologize my ignorance.
I'm confused by the constants $D$, $\kappa$, and $J$ when it comes to torsion of beams. From what I understand $\kappa$ and $J$ are the same ...
1
vote
0answers
67 views
Am I estimating thrust of a ducted fan correctly?
I'm asking if I'm doing this correctly.
I've estimated the thrust of a ducted-fan model aircraft neglecting pressure changes across the duct as follows:
$$F = Q * \rho * (V_e - V_0)$$
$$= Q * rho * (...
1
vote
0answers
35 views
“Freeze”/Mold paper in a certain bent position [closed]
I have a piece of paper (lets says its a A4) and I bent it in a certain way (like a skateboard ramp, I'm holding the ends and the middle kind of falls forming this "ramp" model), but now I need a way ...
1
vote
0answers
70 views
Method to simulate a dipole antenna in salt water?
I am looking to simulate the radiation pattern of a 2.7Ghz half-wavelength dipole antenna immersed in salt water.
I've been using Altair FEKO software to try and accomplish this. I've tried two ...
2
votes
1answer
61 views
How are NPT hole features defined?
I'll be the first to admit that I have always been somewhat confused by best-practice dimensioning standards surrounding pipe threads. While there is a decent amount of literature available online, (...
2
votes
2answers
669 views
Viscoelasticity and Hyperelastic model, history and difference
Actually, I see some papers use viscoelasticity or hyperelastic model for the same materials. It seems to me that those models were invented in different eras, and the hyperelastic is a newer model ...
0
votes
1answer
55 views
How to get the surface area of trajectory [MSC Adams]?
I'm not sure if the upper question is clear enough to understand but here's what I've got:
I've made a model of excavator in Adams View and got trajectory of it's motion (boom, stick, bucket) using ...
0
votes
1answer
54 views
Parametric equations for fan blades
I'm looking for an explicit numerical example of a parametric surface (u, v) |-> (x(u, v), y(u, v), z(u, v)) that models a fan blade like that in the attached picture.
Googling results in NURBS/PDE ...
1
vote
2answers
436 views
Example of real-life problem solved with numerical methods? [closed]
I hope this is a suitable question to ask here.
Well, I'm taking Numerical Methods this semester (also called 'Numerical Analysis' in some places).
The term-assignment is to find a real-life problem ...
4
votes
1answer
79 views
Modelling gas desorption from a still solution (e.g. a beer)
The common way to model or estimate gas (e.g. CO2) desorption rate from a liquid solution is by using an equation similar to this one
$J_{CO_2} = -k_L a(H·C^G_{CO_2} - C^L_{CO_2})$
where $J_{CO_2}$ ...
1
vote
4answers
100 views
Git, Mercurial, others — what's the best system for an engineering team new to version control?
I recently started working with a new team doing detailed energy modeling for all flavors of building projects -- commercial, industrial, residential, new construction, renovations, additions. As the ...
2
votes
0answers
56 views
How to join two beams rigidly?
Hi I am making a beam model using Abaqus. There are two beams created. I wanted to join two beams rigidly in the connection to transfer moments between beams. However, I do not know what connector or ...
1
vote
3answers
181 views
How do you read a blower/compressor curve with multi-curves for inlet guide vanes?
I am trying to apply an existing blower curve in a hydraulic model for a single stage blower with variable inlet diffuser vanes. The variety of curves shown on the plot does not seem to make sense to ...
0
votes
1answer
132 views
How to make datum planes on a cone in Creo?
I am trying to make this
I was able to make the base feature but I am facing problems with the secondary features. So could anyone shed some light on how to make the datum planes on cones.
I made ...
0
votes
1answer
82 views
How does the superposition principle relate to Bernoulli-Euler and Timoshenko beam theory? [closed]
I have a shaft with a bearing in each end, and a large eccentric mass covering the entire "free length" of the shaft.
The attachment of the eccentric mass is done using heat shrinking.
Without ...
1
vote
1answer
69 views
Predicting frequencies, decays, levels, and phases of modes of a circular membrane (drum head)?
I have been working on some acoustic synthesis software for modelling several acoustic instruments. I am using the principle of modal synthesis, where every mode of vibration is individually ...
0
votes
1answer
43 views
Modeling the stiffness of a membrane
I'm trying to model, in MATLAB, a membrane in 2D which has an initial triangle-like shape.
This membrane has pressure acting on it from the inside. There are also some pulling forces in random ...
0
votes
1answer
159 views
What is the advantage of successive linearization?
In this link, two methods have been referred for linearization.
1- offline linearization
2- online linearization
However, I do not understand what is the role of "successive linearization" in the ...
3
votes
2answers
35 views
How to estimate the time cost of interrupting a task and picking it up again later
In terms of personal productivity (single machine scheduling) when a task is interrupted before being done in order to switch to a different task, it incurres a 'tear down' time cost - putting tools, ...
0
votes
1answer
44 views
Thermal Modeling
I have an electronic assembly and part of what it does is to measure and report temperature. The electronics are housed is a plastic enclosure, and there is a small fan blowing out of the enclosure. ...
1
vote
1answer
33 views
simplified acceleration and max speed calculations for a game? [closed]
Are there any simplified formulas that could be used to generate plausible airplane, spaceplane/SSTO, and spacecraft performance specs for a game given some basic vehicle and contextual attributes? By ...
1
vote
1answer
51 views
Explain each of the values output by HEC-RAS
I am looking at a Flood Risk Assessment that uses HEC-RAS to model the predicted levels of flooding on a piece of land. As shown in the attached image, the report lists a number of variables with ...
1
vote
0answers
19 views
How to find the maximum misalignment from vibration?
Consider the system in the (drawn in Paint) image. Assume that there is an input acceleration at the ground defined by a PSD. This acceleration can be in any axis. Points A and B are initially aligned ...
4
votes
1answer
172 views
Questions regarding Cornering Stiffness for RC Car
I am a bachelor's level student tasked with modeling the vehicle dynamics of an RC Car that will be made to drive autonomously. I lack prior experience or particularly specific education with vehicle ...
1
vote
2answers
126 views
Failure of N.R.T.L method to model Phenol / Methylcyclohexane / Toluene system in AspenPlus. Why?
I have an extractive distillation column set up in AspenPlus. Methylcyclohexane (MCH) is expected to come out from the top (in the distillate stream) and the bottoms stream is mostly Toluene/Phenol, ...
1
vote
1answer
232 views
Energy consumption of a boiler
I have a question that maybe will be very easy for you.
I am working on a district heating model using Dymola, and now I have to incorporate a boiler into my model, such as this one.
I was asked to ...
5
votes
1answer
93 views
Would a partial space elevator work? [closed]
Background
The normal space elevator (that reaches from the Earth's surface to a counterweight beyond geostationary) needs a material that's strength/weight ratio is better than any material we have ...
