Questions tagged [modeling]

Use this tag for questions about numerical or analytical modeling and simulation of engineered systems.

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I applied acceleration at the base of model in Abaqus. I ran the model and got the output, the acceleration at the base doesn't match the input. Why?

I am modeling an earthquake in Abaqus. I applied acceleration in the horizontal direction at the base of my model. I plotted the input acceleration. I ran the model and got the acceleration at the ...
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Is there an estimate for the packing density of boxed household items/furniture?

A bit of a silly question, but I'm not sure where else to ask. I've been trying to estimate if it's cost effective to move certain household belongings over a long distance, given the price I could ...
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Viscoelastic modeling, what is wrong with my Boltzmann Superposition integral?

In a similar setup to many Micro-Pipette Aspiration experiments, I have a ramp-and-hold aspiration, and calculate the resulting elevation using the Boltzmann hereditary integral. My aim is to fit the ...
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Simple simulation model of water boiling in a pot?

I want to investigate boiling processes (in the kitchen) by simulation. To this end I assume there is a pot ($m_\mathrm{pot}, C_\mathrm{pot}, T_\mathrm{pot}$) with some water inside ($m_\mathrm{water},...
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Simulinks modeling of 2-loop circuit containing LRC elements

I have been attempting to model the following circuit using KVL and Simulinks: Applying KVL generated these coupled differential equations: $$ 0 = -V + \frac{q_1}{c_1} + R ( \frac{dq_1}{dt} - \frac{...
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Are these section views correct Autodesk inventor

So I used AutoDesk inventor and created this machine part for the purpose of exercise , But it is preferred to not to hatch ribs in my course so is there a way to make it look like image (5 and 6) ? ...
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Autodesk inventor create rib feature failed

It's been kind of painful to create a rib I'm new to inventor while I was trying to create a rib symmetric about the YZ Plane this error keeps popping up
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How to draw hidden rib in Autodesk Inventor

I drew the outer hollowed body and the cylinder on 2 separate parts but I can't figure out how to draw this rib so that it is passes through the centre of the cylinder, a video of a similar example ...
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Tranfer function of non-self regulating process

This system is non-self regulating process with mathematical model : dh/dt = (fi-fo)/C where fi = flow input, fo = flow output, C = tank capacity or volume tank. I want make tranfer function of this ...
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Mathematical model of an hydraulic jack

How to find a mathematical model of this hydraulic jack system? I'm confused about the part when the piston extender, check valve 1 opens and check valve 2 closes, then liquid from the bottom tank ...
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How does one deal with indeterminacy in modeling the motion of vehicles with multiple wheels? (Dynamics Question)

Consider a vehicle with four wheels and suspension (coil and dampers) rolling over an arbitrary surface. What would be the magnitude (not direction) of the normal force on each wheel? Is there a ...
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I’m having trouble converting this orthogonal shape to isometric, I’m only a beginner and would really appreciate some help [closed]

Orthogonal to isometric shape, I need help with this as I’m only a beginner, please help me.
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Sliding-mode control is a model-based technique?

The sliding mode control can be considered a model-based control? In my opinion yes since takes the information of the mathematical model of the system to be controlled handling with possible ...
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Workbench: Explain the difference between the case with bonded contact and the case with the frictional coefficient of 0.01

Explain the difference between the case 1 with bonded contact (top image) and the case 2 (bottom image) with the frictional coefficient of 0.01 For both cases, the top plate has displacement and the ...
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Solidworks - how to make a groove on a double curvature surface

Today, as I was making -for another post - the following part Although, I managed to use a couple of ways to do the above (revolve a sketch, and b) using swept cut) I wondered how would I make ...
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Unstable System. Error Trying to model the Red Bull Stratosphere Free Fall

I tried to model a problem months ago and still I can't solve, I don't want forget this problem so I would like to share what I tried and if you know what is happening with my graph. This is the ...
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Examples of model-based control techniques

I am trying to find out the differences between the model-based control approach and the data-driven one. Surely the main difference is the latter's independence from the information of the ...
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Nominal model and Mathematical model of a real plant [closed]

What is the difference between nominal model and mathematical model of a real plant? I am interested in understanding the difference since I want to understand why in some cases is not the best idea ...
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a model of a solid using trusses to approximate internal stresses?

my question is as follows: could the stresses on a solid body be aproximated with a discrete model based on trusses?, this is, that the result yielded by the analysis of the truss structure will ...
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1 answer
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Modelling of Ball and Beam System

I'm trying to model a basic ball and beam system using Euler-Lagrange Equation. My system looks something like this I have come up with this final Euler-Lagrange Equation: Where JB is the ball's ...
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1 answer
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Linear Nastran model not converging

I am running a SOL 101 linear statics FEA. If I fix down the whole geometry it converges. But anything less than around 90% fix down and it will sit there crunching away at the numbers forever. This ...
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1 answer
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Dynamic model of a two-mass electric drive taking into account the Gear Ratio

Two-mass rotational system has the following form and is represented in following structural diagram. where $\tau_e$, $\omega_1$ and $J_m$ - motor torque, angular velocity and moment of inertia $\...
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How to design an enclosure around the load cell (Beam type)?

Hardware and Electronics Used: Arduino UNO, HX711 ADC Load cell amplifier, Load Cell (2Kg); Currently, I am working on a project which requires me to put load cell along with the other circuitry in an ...
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Modeling torque as surface pressure

Consider a rod with a length of 150 [mm] and a diameter of 44 [mm]. At the left boundary the rod is fixed to a wall. At the right end a torque of 1000 [N m] is applied. The remaining boundaries are ...
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transfer function with constants

I have the following differential equation and I need to obtain the transfer function of Z / P but there are constants so I cannot factor to obtain the relationship, how could I obtain the transfer ...
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propeller air mass flow equation

I am trying to model a hovercraft and I need to obtain an air inlet flow ratio in (kg / s) of a propeller based on its dimensions (it can be the radius) and speed, is there an equation like that? ...
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How do I read this schematic drawing notation for a drill hole?

It's for an NX part. I can't figure out the depths and such. I just know the placement of the 4 holes and that the diameters are 10 mm each.
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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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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 ...
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2 votes
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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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1 answer
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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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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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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 ...
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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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1 answer
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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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2 votes
1 answer
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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 ...
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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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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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1 answer
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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 ...
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4 votes
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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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1 vote
1 answer
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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 ...
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2 votes
0 answers
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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 ...
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2 votes
2 answers
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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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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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1 answer
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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 ...
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1 vote
1 answer
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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, ...
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1 answer
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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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1 answer
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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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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{...
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2 votes
1 answer
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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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