Questions tagged [modeling]
Use this tag for questions about numerical or analytical modeling and simulation of engineered systems.
159
questions
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20 views
Optimal control of the gradient type PDE
I recently encountered the following optimal control problem.
The purpose of the system is to find the parameter $x$ at which the maximum or minimum of the function $f$ a is reached. $x$ is unknown to ...
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2answers
47 views
Trouble with an actuator on a Robotics SolidWorks design. Any ideas why?
I am in the process of developing a robotics design on SolidWorks.
The goal of this design is to tilt a platform using 2 actuators.
My design utilizes 2 indirect actuators that are separately powered ...
2
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0answers
20 views
Is there any formula to model the effective Young's Modulus of a fluid-filled spherical shell?
I am creating composites of a host epoxy and filler particles which are thin-walled fluid-filled shells. Using the Halpin-Tsai equations, for example, I can predict the bulk composite Young's modulus ...
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1answer
17 views
Thermal Capacitance - Convention for Modeling of Electrical Equivalent
As an EE, I am very comfortable with the mapping of thermal quantities to their electrical equivalents. However, understanding how thermal capacitances should be connected is driving me crazy.
this ...
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1answer
24 views
differential drive vehicle in screen coords
differential drive vehicle in world frame
what would change in the kinematic model of the differential drive vehicle if i wanted to simulate it
using pygame module in python ( pygame or opencv or any ...
2
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0answers
25 views
Problem in the inverse kinematic model of a car like vehicle?
I'm a electrical engineering student and i am building a simulation of a car like vehicle .
As I understand it:
The input for the forward kinematic model are the control
variables and the output is ...
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0answers
30 views
Are gas distribution networks tree-like?
I was wondering, if it is justified to say, that gas distribution network graphs (primarily in Europe) are typically tree-like. By gas distribution networks I mean municipal and regional distribution ...
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1answer
44 views
Deriving equation of motion of a 1 degree of freedom system
Before solving this system, note that the rigid bars $\mathrm{\overline{OA}}$ and $\mathrm{\overline{OB}}$ are rotating about point $\mathrm{O}$, not their respective CGs. To account for this two ...
3
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0answers
25 views
Solidworks Loft error (guide curve not intersecting with profiles)
I am trying to add 'finger grooves' to my model of a brake lever and want to use a loft to do so. I have created (to my knowledge) all required sketches for the loft but SW gives me an error when ...
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1answer
35 views
Autodesk Inventor Make Holes on Different Edges Based on One Line
I need to invent a construction based on standard square tubes with holes placed in certain distance from each other and from ends of the tubes:
I also need to imagine the tube with holes as a ...
1
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0answers
20 views
Setup Invention Process in Engineering CAD Software
I need to develop a collapsible metal construction. I have a few specific prerequisites. Generally speaking, it will be something like a big construction toy, but not be a toy. It has the specific ...
2
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2answers
29 views
Force Transmission in Flexible Tools such as this tool
In general, I want understand how the Power transmission in flexible tools works such as this flexible pick up tool in this link: https://www.youtube.com/watch?v=TLbCatz4Pnkv=q9AkmsTNLkY . ...
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0answers
29 views
Superimposing a Vector Field onto a Toroid in Matlab
I am a systems and control PhD student in Aerospace Engineering. Currently, I am trying to create a wind shear model of a toroidal thermal "bubble" in Matlab similar to the one in this paper (shown ...
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0answers
73 views
Pspice ac sweep problem
I want to run an AC sweep from 1 Hz - 10 MHz and calculate the output of the circuit (the voltage on RL), however spice shows that my voltage is 0 in a lot of parts that it shouldn't. I believe the ...
1
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1answer
39 views
Help understanding this dimension sheet
I am trying to currently model a few parts for my custom 3D Printer. I have found some flanged lead screw nuts i'm going to use, but i'm having a hard time reading the dimension sheet. Specifically, ...
0
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1answer
45 views
Calculate forces/ torques on a parallel spring array
I am stuck on the calculation of forces on a certain system involving parallel springs.
The schematic of the system is as follows:
The lower plane is fixed and the upper plane movable. There is a ...
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0answers
6 views
Magnetization characteristics and static characteristics of SR motor from Ansys Maxwell. Part II
Continuing the topic:
Magnetization characteristics and static characteristics of SR motor from Ansys Maxwell
Are there any people in the community who are more or less familiar with Ansis Maxwell's ...
2
votes
1answer
122 views
linearizing a non linear state space equation
I have this 1-DOF helicopter simulator.
The motor's armature resistance is $R$, inductance $L$ and motor constant $K$ and reaction torque on the motor shaft is $Ļ$. $T$ is equal to $k_1w_2^2$ and $...
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0answers
35 views
Lagrangian of a piezoelectric material
I'm confused about the Lagrangian of a piezoelectric material. I've seen multiple sources which seem to contradict each other.
The way I personally approach the problem is the following ($\underline{...
2
votes
1answer
55 views
Modeling the torque of a real motor
I am trying to control a real inverted pendulum by means of a DC motor, for this I must model the torque of the motor, the work I've done in this direction is the following (which I believe is right):
...
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0answers
9 views
Increase in target emission rate (TER) when using a air source heat pump (ASHP) in standard assessment procedure (SAP) calculation
I am running a SAP calculation on a proposed building which will be utilising a 8.5 kW ASHP for space and water heating. I am also running a comparative analysis against a mains gas boiler to show the ...
2
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0answers
23 views
How does one calculate the principial component stresses in an ellipsoidal tank due to head pressure?
I have parameterized the following common bulkhead tank, which has cylindrical walls (easy enough) and ellipsoidal bulkheads. The upper tank is full of a fluid of density 800 kg/m^3 and the lower is ...
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0answers
23 views
Slow integration of system ODE under specific conditions in adsorption problem
I am trying to solve the system of ODEs below. I am applying the finite differences to z, so I get a system of ODE that I can solve with a solver like ode45.
The problem is that under the conditions ...
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0answers
22 views
Water distribution through N x Needle orifices
Consider a water distribution setup consisting of a feeder line blocked at one end but having 100 needle outlets all the same size. The feeder line cross sectional area is much greater than a needle ...
2
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0answers
17 views
Custom Models in Process Engineering
I'm using Aspen Custom Modeler to create a model to be used in Aspen Plus and Aspen Plus Dynamics, and I'm having trouble figuring out how to code the mass balance, energy balance, etc. I'm ...
3
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1answer
206 views
How to model Motor Windings in Solidworks?
I want to model a DC motor in order to eventually do some simulations (temperature/cooling related) and I'm wondering what is the best way to model the motor windings?
I've seen a few video's on how ...
2
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0answers
19 views
How do I correctly model this system of torsion springs?
I am currently designing a symmetric parallel mechanism that can be modeled as follows:
Here, $\tau^j$ denotes actuator moments and $k_i$ are torsion springs constants. For a specific point in the ...
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1answer
78 views
How to obtain plant parametric model of given system?
Consider the system:
$$ y(s)=b\frac{e^{āsĻ}}{s+a}u(s) $$
where a,b are unknown, constant parameters and $\ Ļ>0 $ is an unknown delay constant. How can I obtain a plant parametric model for this ...
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0answers
13 views
how to get more number variance compared as the csv output file of two model stl files in Cloudcompare
we are using the CloudCompare for comparing two mouth STL model for Final doctoral theses, like works done in this paper(pdf) shown blow:
and the instruction said here:
so i have tried to insert the ...
2
votes
1answer
127 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
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0answers
16 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
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1answer
110 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, ...
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1answer
21 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 ...
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1answer
43 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?
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0answers
39 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 ...
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3answers
53 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 ...
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0answers
68 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
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1answer
79 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
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1answer
22 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 ...
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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
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1answer
115 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 ...
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0answers
55 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
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0answers
29 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
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1answer
114 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 ...
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0answers
17 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
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1answer
28 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(\...
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2answers
45 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 ...
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0answers
29 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
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2answers
101 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
516 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 ...
