[Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Freddy Rietdijk - 2012-11-26 14:39:08 Attachments: Message as HTML ```Hi, Soon I start working on my master thesis which will likely involve writing code for Statistical Energy Analysis or SEA. SEA is used within vibroacoustics to model the flow of acoustic power through a vibrating system. An example is modeling the vibrations in cars due to the engine. In general SEA is used in the high-frequency region whereas FEA is used in the low-frequency region. In SEA a geometry is first designed. Then, the relevant components are modeled as subsystems. These subsystems are connected through couplings. Power is added into the system through excitation of one or more subsystems. Power dissipation in subsystems and couplings are modeled using loss factors. Finally, a single matrix composed of loss factors, modal densities and input powers, are solved resulting in the modal energies of each subsystem, from which their vibration or noise levels can be calculated. While I have a good understanding about this method, and already have a Python code capable of SEA, I do not know much about geometries, and I was therefore looking for a geometry kernel. Having seen this project I am now actually thinking of writing it as a module for FreeCAD. There are two questions I have, for which I wasn't able to find the answers. - Is there a possibility to detect junctions and determine their size? So the length if an edge is 'shared', or area if for instance two solids are connected. - Is there yet a material class? I found somethingabout it on the wiki, and it seems to be in the design stage. Since I will also need a material class I could join those working on it. Thanks, Freddy Rietdijk ```

 [Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Freddy Rietdijk - 2012-11-26 14:39:08 Attachments: Message as HTML ```Hi, Soon I start working on my master thesis which will likely involve writing code for Statistical Energy Analysis or SEA. SEA is used within vibroacoustics to model the flow of acoustic power through a vibrating system. An example is modeling the vibrations in cars due to the engine. In general SEA is used in the high-frequency region whereas FEA is used in the low-frequency region. In SEA a geometry is first designed. Then, the relevant components are modeled as subsystems. These subsystems are connected through couplings. Power is added into the system through excitation of one or more subsystems. Power dissipation in subsystems and couplings are modeled using loss factors. Finally, a single matrix composed of loss factors, modal densities and input powers, are solved resulting in the modal energies of each subsystem, from which their vibration or noise levels can be calculated. While I have a good understanding about this method, and already have a Python code capable of SEA, I do not know much about geometries, and I was therefore looking for a geometry kernel. Having seen this project I am now actually thinking of writing it as a module for FreeCAD. There are two questions I have, for which I wasn't able to find the answers. - Is there a possibility to detect junctions and determine their size? So the length if an edge is 'shared', or area if for instance two solids are connected. - Is there yet a material class? I found somethingabout it on the wiki, and it seems to be in the design stage. Since I will also need a material class I could join those working on it. Thanks, Freddy Rietdijk ```
 Re: [Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Christian Gagneraud - 2012-11-26 16:45:18 ```Hi Freddy, I can't help you on anything, but what you want to do sounds really great! Best of luck! Chris On 26/11/12 14:11, Freddy Rietdijk wrote: > Hi, > > Soon I start working on my master thesis which will likely involve > writing code for Statistical Energy Analysis or SEA. SEA is used > within vibroacoustics to model the flow of acoustic power through a > vibrating system. An example is modeling the vibrations in cars due to > the engine. In general SEA is used in the high-frequency region > whereas FEA is used in the low-frequency region. > > In SEA a geometry is first designed. Then, the relevant components are > modeled as subsystems. These subsystems are connected through > couplings. Power is added into the system through excitation of one or > more subsystems. Power dissipation in subsystems and couplings are > modeled using loss factors. Finally, a single matrix composed of loss > factors, modal densities and input powers, are solved resulting in the > modal energies of each subsystem, from which their vibration or noise > levels can be calculated. > While I have a good understanding about this method, and already have > a Python code capable of SEA, I do not know much about geometries, and > I was therefore looking for a geometry kernel. Having seen this > project I am now actually thinking of writing it as a module for FreeCAD. > > There are two questions I have, for which I wasn't able to find the > answers. > > * Is there a possibility to detect junctions and determine their > size? So the length if an edge is 'shared', or area if for > instance two solids are connected. > * Is there yet a material class? I found something > ; > about it on the wiki, and it seems to be in the design stage. > Since I will also need a material class I could join those working > on it. > > Thanks, > > Freddy Rietdijk > > > ------------------------------------------------------------------------------ > Monitor your physical, virtual and cloud infrastructure from a single > web console. Get in-depth insight into apps, servers, databases, vmware, > SAP, cloud infrastructure, etc. Download 30-day Free Trial. > Pricing starts from \$795 for 25 servers or applications! > http://p.sf.net/sfu/zoho_dev2dev_nov > > > _______________________________________________ > Free-cad-general mailing list > Free-cad-general@... > https://lists.sourceforge.net/lists/listinfo/free-cad-general -- Christian Gagneraud, Embedded systems engineer. Techworks Marine 1 Harbour road Dun Laoghaire Co. Dublin Ireland Tel: + 353 (0) 1 236 5990 Web: http://www.techworks.ie/ -- Visit us at the International Conference on Ocean Energy Dublin 17-19 Oct http://www.icoe2012dublin.com/ ```
 Re: [Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Hugo Oosterkamp - 2012-11-27 08:40:19 ```Hi Freddy, I have no clue about SEA, just warn your friends you might have less time for them because working with FreeCad is kind of addictive. Cheers Hugo Hugo Oosterkamp Water and Sanitation || Mozambique || +258 84 763 3777 || hugo@... || http://www.oosterkamp.eu|| skype: hugo.oosterkamp ------------------------------------------------------------------------ On 11/26/2012 06:26 PM, Christian Gagneraud wrote: > Hi Freddy, > > I can't help you on anything, but what you want to do sounds really great! > Best of luck! > > Chris > > On 26/11/12 14:11, Freddy Rietdijk wrote: >> Hi, >> >> Soon I start working on my master thesis which will likely involve >> writing code for Statistical Energy Analysis or SEA. SEA is used >> within vibroacoustics to model the flow of acoustic power through a >> vibrating system. An example is modeling the vibrations in cars due to >> the engine. In general SEA is used in the high-frequency region >> whereas FEA is used in the low-frequency region. >> >> In SEA a geometry is first designed. Then, the relevant components are >> modeled as subsystems. These subsystems are connected through >> couplings. Power is added into the system through excitation of one or >> more subsystems. Power dissipation in subsystems and couplings are >> modeled using loss factors. Finally, a single matrix composed of loss >> factors, modal densities and input powers, are solved resulting in the >> modal energies of each subsystem, from which their vibration or noise >> levels can be calculated. >> While I have a good understanding about this method, and already have >> a Python code capable of SEA, I do not know much about geometries, and >> I was therefore looking for a geometry kernel. Having seen this >> project I am now actually thinking of writing it as a module for FreeCAD. >> >> There are two questions I have, for which I wasn't able to find the >> answers. >> >> * Is there a possibility to detect junctions and determine their >> size? So the length if an edge is 'shared', or area if for >> instance two solids are connected. >> * Is there yet a material class? I found something >> ; >> about it on the wiki, and it seems to be in the design stage. >> Since I will also need a material class I could join those working >> on it. >> >> Thanks, >> >> Freddy Rietdijk >> >> >> ------------------------------------------------------------------------------ >> Monitor your physical, virtual and cloud infrastructure from a single >> web console. Get in-depth insight into apps, servers, databases, vmware, >> SAP, cloud infrastructure, etc. Download 30-day Free Trial. >> Pricing starts from \$795 for 25 servers or applications! >> http://p.sf.net/sfu/zoho_dev2dev_nov >> >> >> _______________________________________________ >> Free-cad-general mailing list >> Free-cad-general@... >> https://lists.sourceforge.net/lists/listinfo/free-cad-general > ```
 Re: [Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Gene Heskett - 2013-01-02 16:14:51 ```On Wednesday 02 January 2013 10:57:51 Hugo Oosterkamp did opine: > Hi Freddy, > > I have no clue about SEA, just warn your friends you might have less > time for them because working with FreeCad is kind of addictive. > I can't say as I'd agree with that. FreeCad's use of an internal web browser to display its help, while leaving no (obvious) way to get back to the work in progress is far more maddening than it is addictive. That continual loss of the part you just started to draw means that in 2 years of fooling with it as a new bee, I have yet to complete the drawing of a box to a given set of dimensions. When the only way back out of the web browser functions is to quit & restart from the init screen, it isn't at all conducive to a newbie trying to learn how it works, because the only thing he wanted to do was a simple 3d drawing and once the browser takes over, there seems to be no way out. So I quit it & restart 3 or 5 times looking for a way to get back to the box I had on screen when I clicked on the help, then quit it for good & go back to drawing my stuff on paper. Maybe I should run 2 copies on 2 workspaces? That works, but what about the user who may not have 4Gb of memory? > Cheers > > Hugo > > Hugo Oosterkamp > > Water and Sanitation || Mozambique || +258 84 763 3777 || > hugo@... || http://www.oosterkamp.eu|| skype: hugo.oosterkamp > > ------------------------------------------------------------------------ > > On 11/26/2012 06:26 PM, Christian Gagneraud wrote: > > Hi Freddy, > > > > I can't help you on anything, but what you want to do sounds really > > great! Best of luck! > > > > Chris > > > > On 26/11/12 14:11, Freddy Rietdijk wrote: > >> Hi, > >> > >> Soon I start working on my master thesis which will likely involve > >> writing code for Statistical Energy Analysis or SEA. SEA is used > >> within vibroacoustics to model the flow of acoustic power through a > >> vibrating system. An example is modeling the vibrations in cars due > >> to the engine. In general SEA is used in the high-frequency region > >> whereas FEA is used in the low-frequency region. > >> > >> In SEA a geometry is first designed. Then, the relevant components > >> are modeled as subsystems. These subsystems are connected through > >> couplings. Power is added into the system through excitation of one > >> or more subsystems. Power dissipation in subsystems and couplings > >> are modeled using loss factors. Finally, a single matrix composed of > >> loss factors, modal densities and input powers, are solved resulting > >> in the modal energies of each subsystem, from which their vibration > >> or noise levels can be calculated. > >> While I have a good understanding about this method, and already have > >> a Python code capable of SEA, I do not know much about geometries, > >> and I was therefore looking for a geometry kernel. Having seen this > >> project I am now actually thinking of writing it as a module for > >> FreeCAD. > >> > >> There are two questions I have, for which I wasn't able to find the > >> answers. > >> > >> * Is there a possibility to detect junctions and determine their > >> > >> size? So the length if an edge is 'shared', or area if for > >> instance two solids are connected. > >> > >> * Is there yet a material class? I found something > >> > >> >> Material_data_model> about it on the wiki, and it seems to be in > >> the design stage. Since I will also need a material class I > >> could join those working on it. > >> > >> Thanks, > >> > >> Freddy Rietdijk > >> > >> > >> --------------------------------------------------------------------- > >> --------- Monitor your physical, virtual and cloud infrastructure > >> from a single web console. Get in-depth insight into apps, servers, > >> databases, vmware, SAP, cloud infrastructure, etc. Download 30-day > >> Free Trial. > >> Pricing starts from \$795 for 25 servers or applications! > >> http://p.sf.net/sfu/zoho_dev2dev_nov > >> > >> > >> _______________________________________________ > >> Free-cad-general mailing list > >> Free-cad-general@... > >> https://lists.sourceforge.net/lists/listinfo/free-cad-general > > ------------------------------------------------------------------------ > ------ Monitor your physical, virtual and cloud infrastructure from a > single web console. Get in-depth insight into apps, servers, databases, > vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. > Pricing starts from \$795 for 25 servers or applications! > http://p.sf.net/sfu/zoho_dev2dev_nov > _______________________________________________ > Free-cad-general mailing list > Free-cad-general@... > https://lists.sourceforge.net/lists/listinfo/free-cad-general Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: ; is up! My views ; "May your future be limited only by your dreams." -- Christa McAuliffe I was taught to respect my elders, but its getting harder and harder to find any... ```
 Re: [Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Yorik van Havre - 2013-01-02 17:59:22 Attachments: Message as HTML ```On Jan 2, 2013 1:16 PM, "Gene Heskett" wrote: > I can't say as I'd agree with that. FreeCad's use of an internal web > browser to display its help, while leaving no (obvious) way to get back to > the work in progress is far more maddening than it is addictive. Just close the browser tab, you still have your document tab open, simple as that... ```
 Re: [Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Gene Heskett - 2013-01-03 02:34:19 ```On Wednesday 02 January 2013 17:53:00 Yorik van Havre did opine: Message additions Copyright Wednesday 02 January 2013 by Gene Heskett > On Jan 2, 2013 1:16 PM, "Gene Heskett" wrote: > > I can't say as I'd agree with that. FreeCad's use of an internal web > > browser to display its help, while leaving no (obvious) way to get > > back to the work in progress is far more maddening than it is > > addictive. > > Just close the browser tab, you still have your document tab open, > simple as that... What tab? A click on getting started is displayed in the freecad workspace, with a new tab with 3 icons in the tab is opened at the lower left of the workspace, and if that tab at the lower left is clicked on its right hand icon, which I assume is the close button, then that tab goes away leaving a blank grey textured work area with the same old data box, no data other in it, on the right edge of that screen. Not terribly helpful to a newbie. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: ; is up! My views ; I think there's a world market for about five computers. -- attr. Thomas J. Watson (Chairman of the Board, IBM), 1943 I was taught to respect my elders, but its getting harder and harder to find any... ```
 Re: [Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Yorik van Havre - 2013-01-03 13:09:58 Attachments: Message as HTML ```Hm that's indeed the default behaviour if you have NO document open. You then have to press the "create new document" button. There is an option in the preferences to always create a new blank document at startup. But if you are already working on something, like you said in a previous post, then closing the browser tab leaves you with that document tab open. In fact there is even no need to close the browser tab, just switch between them. Honestly you're the first person ever to complain about that... ```
 Re: [Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Gene Heskett - 2013-01-03 19:43:52 ```On Thursday 03 January 2013 14:14:08 Yorik van Havre did opine: Message additions Copyright Thursday 03 January 2013 by Gene Heskett > Hm that's indeed the default behaviour if you have NO document open. You > then have to press the "create new document" button. There is an option > in the preferences to always create a new blank document at startup. > > But if you are already working on something, like you said in a previous > post, then closing the browser tab leaves you with that document tab > open. In fact there is even no need to close the browser tab, just > switch between them. Honestly you're the first person ever to complain > about that... Well, I would think that if I have drawn a square, then find I need to translate my inch measurements to metric because FreeCad only runs in metric, goto the help screen to see if I can look something up, maybe find find what I want, then return to my drawing by closing the tab that opened, my work should still be there. It is not. Where did it go? DamnedifIknow, so I quit & restart. A blank screen, even a pretty textured one, is in this case somewhat less useful than some graph paper, where I can at least pencil in notes as to the real world measurements. Even if I could manage to make some nice accurate drawings with it, your output format isn't conducive to a quick, export it in gcode solution. At this point I haven't been able to explore the export options simply because until there is something to export, the option is greyed out. I am the new bee here, thats very plain, with near zero preconceived ideas about how this should work, so I approach it with a block of metal in one hand, and a hammer & chisel on the table with intentions of removing what isn't part of the elephant. But everyone has to start someplace, and so far I have not managed to find the magic twanger (oops, that dates me as an old fart, beyond any reasonable doubt) that even lets me get started. When you cannot exit the Getting Started screen without totally destroying what you have done, its apparent stability, although that can be debated, as it can be destroyed by making a typu in the data entry fields because they do NOT take a mouse click WHERE you want to type, and pretty startup face just aren't enough incentive to keep on hacking until one has actually drawn something useful. Something as useful from square one as lightwave was on the amiga in the 1990's, seems not to be available for linux. You seem to start at 2nd base, with no means of instructing the newbie how to get his first hit, and then steal the next base when the pitcher is looking the other way. And as near as I can tell, home plate is fenced off by the lack of gcode exportation, so actually scoring a finished run isn't possible. I'd love to be proven wrong! Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: ; is up! My views ; People in general do not willingly read if they have anything else to amuse them. -- S. Johnson I was taught to respect my elders, but its getting harder and harder to find any... ```
 Re: [Free-cad-general] Statistical Energy Analysis module for FreeCAD From: Yorik van Havre - 2013-01-03 20:49:45 Attachments: Message as HTML ```Well I don't know what I can respond... Indeed, freecad doesn't do gcode yet. That's being worked on, though. As for loosing your document tab when opening a browser tab, if it is indeed what is happening to you, it might be a bug. But I think maybe freecad is still a bit rough for your needs, it is a young program, and it will still take time before its interface reaches a state where it is totally friendly and usabe to everyone. ```