Questions about the dynamics of a system. Currently there is a very large scope ranging from from dynamics in mechanics, vehicle and flight dynamics, to system dynamics and fluid dynamics.
Questions tagged [dynamics]
322 questions
13
votes
4 answers
Derivation for bridge natural frequency estimate in Eurocodes
The Eurocodes gives the following equation for estimating a "simply supported bridge subject to bending only"*:
$$n_0 = \frac{17.75}{\sqrt{\delta_0}}$$
Where
$n_0$ is the natural frequency in hertz
$\delta_0$ is the deflection at mid-span under…
thomasmichaelwallace
- 934
- 2
- 10
- 27
11
votes
1 answer
Detailed dimensions of an aircraft engine compressor blade
I am working on rub-induced vibrations in compressor stages of aircraft engines. The work is carried out in partnership with a company, therefore there is a limited amount of it that could be published openly.
Is it feasible to release open source…
Nicolas
- 332
- 3
- 15
9
votes
1 answer
What is the benefit of additional planetary gears?
A planetary gear is a gear that rotates not around an axle but around another gear known as a sun gear, or star gear. I have designed prototype systems in the past that used a single planetary gear rotating around a rotating gear. However since then…
Sam Weston
- 607
- 1
- 5
- 15
9
votes
4 answers
How does load force impact load inertia?
I am trying to simulate a winch as a speed-regulated motor that works through a gearbox to lift a mass. The output of the gearbox is a drum, which rotates to accumulate cable.
I feel comfortable converting the mass to a moment of inertia and I also…
Chuck
- 3,575
- 15
- 32
8
votes
1 answer
Dynamics Simple Pulley System - Stuck on the Process
Have spent hours poring over this homework question but am having difficulty getting the right process going to solve the problem. I don't really know where to start, and I'd really be grateful if someone could show me the ropes (pun intended ^_^).…
Elisa Accordino
- 81
- 1
- 4
8
votes
2 answers
Moment equation from dynamics differs with equations from physics & statics. Where did I go wrong?
In my dynamics class, we're being asked to solve the following problem:
My Attempt:
Since I'm given the initial velocity, final velocity, and distance, I solved for the acceleration of the plane using kinematics:
$a = \frac{v_f^2 - v_i^2}{2d} =…
Chris Forsyth
- 81
- 1
8
votes
2 answers
System Dynamics Modeling
I am trying to model this system but am having difficulties in setting up the equations of motion. This is a simplified model of a motorcycle suspension system, where P is the ground in the image below. In addition, the variable $u$ is the input to…
Josh Pilipovsky
- 461
- 2
- 7
7
votes
2 answers
Unexpected Results from my Transfer Function
I have a system that can be modeled with the following picture:
There is a mass $m$ connected to a spring $k$ and a dashpot $d$. These are both connected to another dashpot $c$. A force $F(t)$ is applied at the junction.
After some effort tackling…
anonymouse
- 357
- 2
- 9
7
votes
1 answer
What is the equivalent moment of inertia of a two-pivot pendulum?
I am working on a system that consists of a hanging-pendulum thrust balance with two pivot points, one in the front and one in the back There is a heavy weight applied in the front. I can change the position of the center of gravity by applying…
idontexist
- 71
- 1
7
votes
3 answers
How do large turbines deal with asymmetry and beat arising from those?
A large turbine used in an electric plant can easily have 10+ meters in diameter and rotate at 70+ RPM. Should any asymmetry occur the rotating turbine will produce beat which will sooner or later destroy the plant. Crafting a turbine that large and…
sharptooth
- 2,129
- 19
- 28
6
votes
2 answers
Feedback control of two-link planar manipulator
TL;DR: how can I calculate the disturbance at each joint due to coupling forces in a two-link planar robot manipulator actuated by two independent DC motors?
I'm studying control theory and trying to work through a simple example using a two-link…
user2398029
- 113
- 1
- 8
6
votes
1 answer
Dynamics of structures: combined plane stress and plane strain conditions
Problem statement
For an engineering project in school, we are checking the stability in the longitudinal direction of an apartment building, taking into account the dynamic effect of earthquakes. For this, we are making a two-dimensional finite…
CJT
- 61
- 1
6
votes
1 answer
Hovercraft design parameters
My washing machine broke down recently, and they replaced the motor. The old motor was not broken,
as far as I could tell; the sensor that told the CPU that the drum was balanced was what was out of
order. At any rate now I have a perfectly decent…
jamesson
- 169
- 3
6
votes
3 answers
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 dynamics so I have been studying the field a bit,…
user14808
6
votes
2 answers
Linearization of dynamic equations/transfer function in control theory
I've gone through a control theory course, and after looking back at what we covered and how the subject was taught to us, I still have quite a few questions (which I unfortunately did not ask in class). As such, I thought I'd ask a few of them…
InquisitiveInquirer
- 313
- 2
- 7