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Robot Structural Analysis

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Active Contributor
GordonSharp1992
Posts: 36
Registered: ‎02-10-2014

frame

02-26-2014 05:37 AM in reply to: GordonSharp1992

hello

can you help

i have attached both a paint file to decribe my problem and the autosad file to let u have a look

please can u help

thank you

gordon

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Rafal.Gaweda
Posts: 5,340
Registered: ‎04-26-2010

Re: frame

02-26-2014 07:16 AM in reply to: GordonSharp1992
What is the question?
Paint file missinig.


Rafal Gaweda
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Active Contributor
GordonSharp1992
Posts: 36
Registered: ‎02-10-2014

Re: frame

02-26-2014 08:49 AM in reply to: Rafal.Gaweda

here it sorry

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Active Contributor
Ken_Marsh
Posts: 39
Registered: ‎03-12-2013

Re: frame

02-26-2014 04:07 PM in reply to: GordonSharp1992

I guess I'm not understanding what is so complicated about this problem.  If you need elastic releases at those joints, just use member end release and specify an elastic stiffness in the release for that direction.

The beam should be modeled across both supports and extending out.  It's just one beam.  Apply support conditions and loads then analyze.

 

Where are you getting hung up? 

 

 

Ken Marsh
Owner Marsh API
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Active Contributor
Ken_Marsh
Posts: 39
Registered: ‎03-12-2013

Re: frame

02-26-2014 04:21 PM in reply to: Ken_Marsh

This book http://tiny.cc/ARSAP2014_Book has a good section on member end releases and modeling supports and members. 

Ken Marsh
Owner Marsh API
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Rafal.Gaweda
Posts: 5,340
Registered: ‎04-26-2010

Re: frame

02-27-2014 12:01 AM in reply to: Ken_Marsh

You can do it exactly as it is in pdf 

 

rotfr.jpg



Rafal Gaweda
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Active Contributor
GordonSharp1992
Posts: 36
Registered: ‎02-10-2014

Re: frame

02-27-2014 07:00 AM in reply to: GordonSharp1992

thank u !

i understand this thank you

is there anyway i can design the node with rotational stiffness ?!

i want to make the frame less rigid, so i want more deflection at node 3.

basically the first desgin i want is to be completely rigid so gives litlle deflection . then the second desgin to be semi rigid/ pinned, so elastic at the two joints. do u understand . will i have to increase the stiffness ?  or do i have to degin the acdtual nodes ? as what u have shown me is the members .

but if i model the nodes how do i connect them up with each other as i get nodes not connected to the frame ?!

thanks

 

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Active Contributor
Ken_Marsh
Posts: 39
Registered: ‎03-12-2013

Re: frame

02-27-2014 07:04 AM in reply to: GordonSharp1992

The release definition that Rafal has shown above is introducing rotational stiffness in the connection between the vertical members and the horizontal members.  If you want to first design as rigid, do not add member releases at the ends of the vertical member.  When you are ready to design for semi-rigid, you add the release with elastic stiffness as shown to both ends of the vertical member. 

 

does that help? 

Ken Marsh
Owner Marsh API
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Active Contributor
GordonSharp1992
Posts: 36
Registered: ‎02-10-2014

Re: frame

02-27-2014 07:15 AM in reply to: Ken_Marsh

yes this helps thanks ! just wandering how would i make it less rigid ? increase the stifness or decrease ?! i want the structure to fail more at the end of the cantilever but changinging to elastic doesnt do this when i feel it should as it is less rigid ?!

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Rafal.Gaweda
Posts: 5,340
Registered: ‎04-26-2010

Re: frame

02-27-2014 07:33 AM in reply to: GordonSharp1992

 increase the stifness or decrease ?! 

 

Guess !

 

elasticrot.jpg



Rafal Gaweda
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