Questions tagged [modeling]
Use this tag for questions about numerical or analytical modeling and simulation of engineered systems.
166
questions
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12 views
Find orientation of reference nodes in Abaqus
I am constructing a simplified model of a pontoon-supported floating bridge in Abaqus. I have chosen to represent the pontoons as one-noded user-elements defined from the mass and stiffness matrix for ...
2
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2answers
75 views
When can the thermal and mechanical energies of a fluid control volume be considered separately?
For a fixed control volume of a fluid, the conservation of energy equation is typically written as something like
$$\dot{Q} - \dot{W} = \frac{\text{d}}{\text{d}t}\iiint_{CV} \left( \hat{u} + \frac12 V^...
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0answers
30 views
Are there examples of spring-mass-damper system that exhibit increasing growth in an unstable way
Simply, are there examples of spring-mass-damper systems that exhibit unbounded behavior or at least increasing behavior for a period of time. I am trying to do some vibrations research, but I am ...
2
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0answers
11 views
How are circular dependencies dealt with inside MBSE?
How are circular dependencies (best) managed inside of MBSE environments? Let's say I have two properties that are linked to each other / they are linked to properties that affect each other.
How is ...
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0answers
11 views
What is the order of execution in system models?
I'm learning SysML/MBSE right now. In what order is a model "executed", that is: in what order are dependencies between properties reconciled?
For instance, if I have one component/subsystem ...
0
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1answer
42 views
How to model this real-world system to define transfer function for stability?
The system shown is an off-axis drive system that rotates the platform to 60° via a substantially-sized NEMA 34 stepper motor. The axial force required by the stepper/ballscrew assembly has already ...
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0answers
15 views
Magnetomotive forces acting on assembly
Apologies if this is the wrong place to pose this question, or if it is poorly formulated, I would appreciate any help, even if that is pointing me to a place where I can learn more about solving ...
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0answers
36 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
57 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
22 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 ...
1
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1answer
18 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 ...
1
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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 ...
0
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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 ...
-1
votes
1answer
48 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
37 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 ...
1
vote
1answer
39 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
21 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
votes
2answers
30 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 . ...
1
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0answers
32 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 ...
0
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0answers
104 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
vote
1answer
44 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
57 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
10 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
133 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 $τ$. $T$ is equal to $k_1w_2^2$ and $...
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0answers
44 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
58 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
10 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
votes
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 ...
1
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0answers
24 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 ...
1
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0answers
23 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 ...
1
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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 ...
2
votes
1answer
282 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 ...
1
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0answers
21 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 ...
-1
votes
1answer
89 views
How to obtain plant parametric model of given system?
Consider the system:
$$ y(s)=b\frac{e^{−sτ}}{s+a}u(s) $$
where a,b are unknown, constant parameters and $\ τ>0 $ is an unknown delay constant. How can I obtain a plant parametric model for this ...
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0answers
14 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
162 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
vote
1answer
138 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
23 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
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1answer
44 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
40 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
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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
110 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
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 ...
0
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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
vote
1answer
132 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
61 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?
