Questions tagged [modeling]

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

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22 views

rigidity angled steel vs aluminum

I would like to find out the difference of flexing between angled steel vs angled aluminum of the same dimensions under load. Is there a straight-forward way to calculate / simulate this? The size I ...
1 vote
65 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 ...
33 views

How should a stationary suspended spherical tube be modified to incorporate aerodynamic downforce mitigating both fore and aft 45 mph - 120 mph winds?

The question involves this topic; High-wind rollover damage in center-pivot irrigation systems. This study involves the additive engineering possibilities to achieving an aerodynamic remedy ...
1 vote
521 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, ...
45 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 ...
509 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 ...
79 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. ...
257 views

Flux and Normal Derivatives

Could someone please clarify the difference between flux and normal derivatives? I am studying PDE's and I came across Neumann Boundary condition (In this condition, the value of the normal ...
146 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 ...
13 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 ...
34 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 ...
147 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 ...
1 vote
80 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 ...
358 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 ...
491 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 ...
36 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 ...
31 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 ...
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 ...
218 views

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 ...
10 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 ...
20 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 ...
56 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 (...
905 views

Looking for program and file format for CNC Milling

I am creating subwoofer boxes out of MDF or Baltic Birch. My local makerspace has a CNC machine. I am going to make all of the cuts with it. What software is generally used or will work to get a ...
71 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-...
166 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 : ...
90 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 ...
76 views

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 ...
3k 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 ...
1 vote
54 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 ...
37 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 ...
76 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 ...
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 ...
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 ...
43 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
67 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 ...
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 ...
1 vote
50 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 ...
148 views

Holonomic constraint forces using Lagrange multipliers

Consider a multibody robotic system with Lagrangian $$L =\frac{1}{2} \dot{q}^{T}M\dot{q} - V$$ and equations of motion of the form $$M(q)\ddot{q}+C(q,\dot{q})\dot{q}+A^{T}(q)\lambda+N(q)=0$$ where ...
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 ...
1 vote
84 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 ...
72 views

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 ...
1k views

How do I use FEM to derive the torsional constant of an arbitrary shape?

In this question I ask about how to perform a first-principle derivation of the torsional constant of a section. It appears that there is no such analytical derivation for torsional constant, so my ...
1 vote
2k views

How to find the angle of deformation in Ansys APDL?

After solving my problem in APDL, and started doing some post-processing, I want to find how much the deformed shape has rotated (i.e. the maximum angle the furthest node has made comparing with 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 ...
Taking mathematical DOF as: $$DOF= N_{vars}-N_{eqs}$$ How would process, or control degrees of freedom be defined as? Thanks!