# Questions tagged [modeling]

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

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29 views

### Modeling an HVAC system's energy

I'm trying to model the energy consumption on an HVAC system with intermittent stops. As my model main parameters I use the following : A temperature and RH sensor of ambient air The HVAC working ...
138 views

### How to model a two mass-spring-damper system with a bilinear spring with preload

So, first of all hello👋 I'm new to this forum. Concerning my question, the system I want to model is a somewhat slightly more complicated version of a two mass-spring-damper system (than treated in ...
33 views

### Designing Eccentric Motion

I am working on a school project where I have to choose a mechanical motion device and create a 3D model of it. I have chosen https://507movements.com/mm_090.html because it seems adequate for my ...
29 views

### Which way should angles be measured given a coordinate frame, according to convention?

I am building a 2D Electric unicycle model and have a somewhat trivial question concerning convention when defining a coordinate system. The EUC is constrained to move upon flat ground, and a figure ...
12 views

### Computing shear strain in a discrete domain

i am doing a uniaxial test on a body and the body(2D) is discretized to a number of points(x,y)and is assumed to be elastic. the node size is $\Delta x = \Delta y$. Let us assume that force is applied ...
9 views

### How estimate the error of chemkin 2.55 results?

I've been using chemkin 2.55 for preliminary calculations of premixed laminar H_2 and CH_4 combustion and in some of the calculations, the solver fails. There is a way to hypothesize the calculation ...
19 views

### how can i rotate my sketches and revolved items around an axis i've created?

i'm making this thingy thing and i made all my solids for a swept cut without referencing my reference, so now they're all in the wrong place. i only need to move them about the centre of the main ...
51 views

### Creating a state-space representation (.m format, Matlab) via Simcenter 3D (NASTRAN) using Component Mode Synthesis Reduction

I'm trying to create a state-space representation of my FE-model using a "Component Mode Synthesis Reduction" (general form of Craig-Brampton reduction). The picture underneath shows (...
149 views

### State space representation of a 2 tank system

I am figuring out the state space equations of a connected 2-tank system. For the 1st tank, the state space equation is as follows : ...
88 views

### Chemical Process Control - degrees of freedom in a stirred tank heater

I'm taking a course on Process Control, and I've been using Stephanopoulos's Chemical Process Control to study. I have a doubt about the degrees of freedom (DOF) analysis performed in one of the ...
24 views

### Searching for a Library of Simulink models of Fuel cells

I have a task at hand and in order to do that I must create a model library of Simulink/Simscape (or any other similar software) of models. Can I find such models in excess anywhere? The models must ...
1 vote
62 views

### Modeling of Wheel Rolling Resistance

I have been working on longitudinal tire model for a while and constantly encounter problems with the formulation of rolling resistance. Consider one wheel model coming down from a damp. It is a 2DOF ...
• 11
72 views

### How to determine whether a threaded rod will rotate under load

A part of a structure I am designing incorporates a large threaded rod (1") diameter mounted vertically both for structural strength and for the potential to adjust the height of the top mounted ...
41 views

### How to model a driver's appropriate braking for deceleration, and throttle for acceleration for a car moving on a straight road?

A project team within my company is stuck on a conundrum and have asked me for some insights. They want to develop a driver model (mathematical or drawn) where input is the car's velocity profile, and ...
67 views

### Finding and drafting a spline

I'm working with a friend to adapt a BMW steering wheel from the 2010s to his Logitech G20 steering wheel base. Now, the BMW wheel is constrained in depth with a 90° taper, and in rotation with a 48-...
1 vote
50 views

### My ANSYS model meshing is showing problem where I don't see my model and small blue rectangle appears. Is there any way to solve this?

I'm new to ANSYS and just started using it. I encountered a problem when I click the model option; ANSYS Mechanical opens, but there is this blue rectangle, which is supposed to be big and show my ...
35 views

### System identification of Blue Robotics Thruster with Simscape multibody

I have CAD design of a Blue Robotics Thruster 200. The thruster is imported to Simulink. From data given Blue Robotics Thruster 200 have MATLAB system identification toolbox been used to generate ...
67 views

### Validity of dimensionless numbers

Dimensionless numbers are often used when studying complex phenomena such as in fluid dynamics or thermodynamics. In my studies we often used them, especially in these two subjects, where they helped ...
26 views

### Seeking example problems solved using Automated Design Synthesis (ADS) algorithms

Premises. Gary N. Vanderplaats and coworkers at the Naval Postgraduate School in Monterey, California developed the Automated Design Synthesis (ADS) algorithms (software) that have been adapted to ...
229 views

### How to support the columns of a second level of an hypaethral building with reduction in space by height?

In this multi-leveled hypaethral building model there is a problem that the columns of the second floor aren't directly situated on the columns of the first floor. How to support the columns of the ...
• 1
9 views

### how to create a Ti V simulation cell with virtual cell approximation for density functional theory calculations

I would like to understand the method of creating simulation cells using the virtual cell approximation for different compositions of TiV using vasp
34 views

### Make Assembly Load Options unique to each assembly in Siemens NX 12

I have a few assemblies I'm working on. For the most part, each assembly is self-contained in its own folder (assembly file and part files). However, there are a number of common parts that are stored ...
1 vote
78 views

### Why do Eigenmodes of a rigid system also diagonalize the Mass and the stiffness matrix seperately?

To set up my question, I will briefly recap the derivation that is usually given for eigenmodes of a system: If there is no force present, and a body is described by a vector $u$, then the equations ...
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1 vote
65 views

### Matrix Calculation

I would like to Calculate Q. The transpose of U matrix is a 2x5 matrix and U is a 5x2 matrix. Therefore, I was expecting a 5*5 Matrix, which wasn't the case. Can someone please help me to solve Q ...
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57 views

### Error Equation of a Control Loop

I want to calculate the error of a control loop. Therefore, the system and the general processes and models are defined as follows: The equation for error is described as follows: I do not ...
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1 vote
34 views

### Why is the turbulent kinetic energy $k=\overline{v_1'^2}+\overline{v_2'^2}+\overline{v_3'^2}$ even in 2D cases?

I'm writing an essay which partly includes writing about the Reynolds stress model where the dissipation term $\varepsilon_{ij}$ is assumed to be isotropic (since dissipation mostly occurs at small ...
37 views

### What are the physical implications of modelling a rider on a unicycle as a massless rod and spring attached to a point mass?

Foreword This is not an industrial question; I will not profit from any answers, and I am asking because it is the subject of my final year project at university. Also apologies to the US for using ...
30 views

### Mathematical Modelling of Wireless Power Transfer

I am trying to understand the interaction between a transmitting antenna with a certain transmitting power (denoted PTX in the diagram) and how the radiation pattern of the TX antenna is affected by a ...
27 views

### The application of a Fluid (air) cooler on 20mm product, equations for temperature, moisture content and relative humidity (maybe modelling)

I currently have a fluid bed cooler which is cooling fine powder (around 20mm) product which enters upto 80 °C (minimum 40 °C) and leaves at a maximum of 25 °C. The mass flow rate is about 1200 kg/h. ...
1 vote
76 views

### Effect of bracing on a music instrument top - is FEM modal analysis enough to predict this?

I'm currently building a music instrument (string instrument), and I am at the step where one applies certain braces to the soundboard. Since I actually don't know how the bracing will affect the ...
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### Transfer function to get linear velocity from a dc motor system

So I have to create a control system simulation from scratch for the following scenario. For a bicycle-like system, there is a motor attached directly to the rear wheel. From here, the goal of the ...
49 views

### Design? Or something else

When we develop a new technical device (after creating its general concept), we want to implement it. But before we implement it, we must design it. And for this we go through some stages (the list is ...
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### Heat Transfer from variable profile truncated fin in Maple

I have a truncated, triangular fin with a rectangular base (width/thickness "w"). The profile is variable, described by: y=-((y0-yL)/L)*x)+y0 The tip is insulated, wall is a constant ...
26 views

### What is the difference between mathematical and process/control degrees of freedom?

Taking mathematical DOF as: $$DOF= N_{vars}-N_{eqs}$$ How would process, or control degrees of freedom be defined as? Thanks!
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1 vote
48 views

### Running a Dynamic Model as Steady State with Time Varying Inputs

I am attempting to run a dynamic model of a waste heat recovery system (Brayton Cycle with intercooling) on IDAES but I keep getting errors on initilization seemingly no matter what I do. My work ...
22 views

### Building CAD Models for simulations and 3D Printing

Is there a tool that allows you to make changes to models so that they can be used for both 3D printing and static simulations in SolidWorks. For example, I want to have a part printed and to deal ...
76 views

### What are the applications of spontaneous synchronization to engineering?

I came across the amazing phenomena of spontaneous synchronization and how it can be modelled by the Kuramoto Model. I am curious as to spontaneous synchronization has its relevance in engineering. ...
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1 vote
90 views

### Why stopping at the first derivative in conservation equations?

Oftentimes we, as engineers, have to write energy/mass/momentum balances to derive the governing equations for a quantity $\phi(x,t)$ of a physical system. One of many derivations of such balances ...
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163 views

### What is the difference between activity and event in "simulation"?

I am studying about components of a system. The subject is "system simulation/simulation modeling/discrete event system simulation". This is related to electrical, electronics, computer ...
142 views

### How can I eliminate oscillations in Sim-Routing for HydroCAD?

I am currently attempting to model a stormwater system that has a high likelihood of backflow because the proposed basins are interconnected and there are no intervening structures which would impede ...
1 vote
48 views

### 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{...
645 views

### 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) ? ...
1 vote
378 views

### 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
168 views

### 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 ...
1 vote
28 views

### 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 ...
347 views

### 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 ...
1 vote
59 views

### 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 ...
56 views

### 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.
1 vote