Why does not the period change even though shear is included
Moderators: silvia, selimgunay, Moderators
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Why does not the period change even though shear is included
Hi all,
I added "section aggregator" in order to add shear stiffness to the stiffness matrix. however, the period did not change. I did not see any problem with running but i feel like the period should change once the section aggregator is added. Thank you for answer in advance...
here is the part of the section aggregator in my code:
## For wall section
set G_shear [expr 11200.0*$ksi];
set matShearTagWall 3001;
uniaxialMaterial Elastic $matShearTagWall [expr $G_shear*$AgWall];
set matShearTagCB 3002;
uniaxialMaterial Elastic $matShearTagCB [expr $G_shear*$AgCB];
set secWallTag 123;
set secWall2Tag 124;
section Aggregator $secWallTag $matShearTagWall Vy -section $secWallTag_PM;
section Aggregator $secWall2Tag $matShearTagWall Vy -section $secWall2Tag_PM;
## For CB section
set secCBTag 1023;
set secCB2Tag 1024;
section Aggregator $secCBTag $matShearTagCB Vy -section $secCBTag_PM;
section Aggregator $secCB2Tag $matShearTagCB Vy -section $secCB2Tag_PM;
I added "section aggregator" in order to add shear stiffness to the stiffness matrix. however, the period did not change. I did not see any problem with running but i feel like the period should change once the section aggregator is added. Thank you for answer in advance...
here is the part of the section aggregator in my code:
## For wall section
set G_shear [expr 11200.0*$ksi];
set matShearTagWall 3001;
uniaxialMaterial Elastic $matShearTagWall [expr $G_shear*$AgWall];
set matShearTagCB 3002;
uniaxialMaterial Elastic $matShearTagCB [expr $G_shear*$AgCB];
set secWallTag 123;
set secWall2Tag 124;
section Aggregator $secWallTag $matShearTagWall Vy -section $secWallTag_PM;
section Aggregator $secWall2Tag $matShearTagWall Vy -section $secWall2Tag_PM;
## For CB section
set secCBTag 1023;
set secCB2Tag 1024;
section Aggregator $secCBTag $matShearTagCB Vy -section $secCBTag_PM;
section Aggregator $secCB2Tag $matShearTagCB Vy -section $secCB2Tag_PM;
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Re: Why does not the period change even though shear is incl
It should change at least slightly. Just to check you can multiply G by 10000 and see if there is any difference
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Re: Why does not the period change even though shear is incl
Hi Selim,
I also tried that but the period did not change. I am sure that after adding the combined shear stiffness to cross section, I am assigning that combined cross-section to elements used (100% sure). i am guessing i cannot add because of either
- type of element (dispBeamColumn), or
- I am adding force-disp. relation for shear to stress-strain for flexural.
Am i right?
I also tried that but the period did not change. I am sure that after adding the combined shear stiffness to cross section, I am assigning that combined cross-section to elements used (100% sure). i am guessing i cannot add because of either
- type of element (dispBeamColumn), or
- I am adding force-disp. relation for shear to stress-strain for flexural.
Am i right?
Last edited by emrekizilarslan on Thu May 03, 2018 8:58 am, edited 1 time in total.
Re: Why does not the period change even though shear is incl
sorry .. shear aggregator does not work with disp based elemnets, only forced based include shear defo effects if provided in the section.
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- Location: SUNT at Buffalo
Re: Why does not the period change even though shear is incl
Thank you so much for your reply. is there a way to include the shear stiffness externally to fiber model then? i would really appreciate if there is. i cannot use "Flexure-Shear Interaction Displacement-Based Beam-Column Element" as it does not allow to use "P-delta" geometric transfer, which i will need to use.
Re: Why does not the period change even though shear is incl
you cannot use with disp beam element, your only choice is to switch to forcebeam element .. or put element in parallel with a force beam element with negligably small elastic section (can't be too small as has to invert it) and the shear aggregator you are using.
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- Posts: 4
- Joined: Wed Mar 29, 2017 6:21 am
- Location: SUNT at Buffalo
Re: Why does not the period change even though shear is incl
Thank you again. I will try that.