Algodoo and simple vibrations problems
4 posts • Page 1 of 1
Algodoo and simple vibrations problems
Hi !
I currently teach Mechanics to students that are typically 18-19 years old.
I used this year Algodoo for one activity in small classrooms (about 25 students) ; because of the interest that students have found in this approach, I would like to develop more activities based on Algodoo.
In particular, I am interested in comparing the results of analytical models of single-degree-of-freedom oscillating systems (free vibrations and forced vibrations) to those obtained with Algodoo.
I tried some of those I have in mind, and most of them work quite properly (ie agreement between theory and results from simulation). Nevertheless, I have two problems :
- study of free vibrations of a mass linked to two springs (see ex5.6_v3.phn)
- study of transmissibility of vibrations (ie car suspension) (see ex7.2.phn)
Whereas I checked the theoritical results I used to describe these problems, I was not able to find comparable results to those of the simulation with Algodoo.
This is why I am wondering whether the behaviour of the simulated movement in Algodoo is reliable from a quantitative point of view. Any comment on this would be gratefully acknowledged.
I currently teach Mechanics to students that are typically 18-19 years old.
I used this year Algodoo for one activity in small classrooms (about 25 students) ; because of the interest that students have found in this approach, I would like to develop more activities based on Algodoo.
In particular, I am interested in comparing the results of analytical models of single-degree-of-freedom oscillating systems (free vibrations and forced vibrations) to those obtained with Algodoo.
I tried some of those I have in mind, and most of them work quite properly (ie agreement between theory and results from simulation). Nevertheless, I have two problems :
- study of free vibrations of a mass linked to two springs (see ex5.6_v3.phn)
- study of transmissibility of vibrations (ie car suspension) (see ex7.2.phn)
Whereas I checked the theoritical results I used to describe these problems, I was not able to find comparable results to those of the simulation with Algodoo.
This is why I am wondering whether the behaviour of the simulated movement in Algodoo is reliable from a quantitative point of view. Any comment on this would be gratefully acknowledged.
- Attachments
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- ex7.2.phn
- (36.98 KiB) Downloaded 423 times
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- ex5.6_v3.phn
- (23.46 KiB) Downloaded 462 times
- steuti
- Posts: 3
- Joined: Mon Dec 27, 2010 3:55 pm
Re: Algodoo and simple vibrations problems
umm, start from using "perfect geoms" like circles and boxes instead of polygons.
make everything 0 friction and restitution.
turn off air.
make everything 0 friction and restitution.
turn off air.
Dream of Algodoo as game development engine...
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Kilinich - [Best bug reporter 2010]
- Posts: 2098
- Joined: Mon Aug 31, 2009 8:27 pm
- Location: South Russia
Re: Algodoo and simple vibrations problems
Kilinich wrote:umm, start from using "perfect geoms" like circles and boxes instead of polygons.
make everything 0 friction and restitution.
turn off air.
Thanks for your suggestion. I'll try with simple geoms, but why would it change something ?
Btw, I clearly see while monitoring the motion that damping (due to springs or friction, be it with air) is not a problem because the motion has a constant amplitude (no decay of amplitude with time).
For example in the case ex5.6.phn, I have solved the equation of motion with a rk45 scheme and the period of movement is two times larger (roughly) than that given by Algodoo, which seems to indicate that there is "something" independant from damping.
But I do not what up to now !
Thanks for your help
- steuti
- Posts: 3
- Joined: Mon Dec 27, 2010 3:55 pm
Re: Algodoo and simple vibrations problems
The reason why simple geometries work better than polygons is because of the way algodoo collision detection system works.
When asking for help, READ THE STICKIES!
- electronicboy
- Posts: 1694
- Joined: Mon Aug 31, 2009 6:18 pm
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