Robot Structural Analysis Forum
Welcome to Autodesk’s Robot Structural Analysis Forums. Share your knowledge, ask questions, and explore popular Robot Structural Analysis topics.
cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

shear stress , Vu

20 REPLIES 20
SOLVED
Reply
Message 1 of 21
egoze
2267 Views, 20 Replies

shear stress , Vu

hi sir 

i have a problem with shear stress for punching 

the problem is 

when i read the shear stress in robot  give me strange values 

i have done manual calcolation punching for internal l column 

fc=25 mpa ,fy=420 mpa, cover =25mm, thikness=250mm

c1,c2=50cm

pu=1025 kn

Mux=35kn.m

Muy=35kn.m

--------

b0=2.9

jc=0.0585 m^4

Vu max aplied shear = 1.744 mpa

 

 

sir i want to read the Vu from robot how -   

 

see attachments please 

20 REPLIES 20
Message 2 of 21
egoze
in reply to: egoze

im looking to hear from you 

Message 3 of 21
chrismcc
in reply to: egoze

Hello,

Assuming you have parameter set to middle, the values of shear stress you are seeing are 1.5 x the average shear for a rectangular section, so your 1.744 (average) would show up as 2.62 at the middle of the rectangular cross section and 0 at the upper and lower.  Try it on a simple span beam to verify.

Hope this helps a  little.

Regards

Chris

Message 4 of 21
egoze
in reply to: egoze

thank you chrismcc  for help.

 

 

Dear sir  Rafal 

 

im really confused for reading shear stress in robot 

i attach the manaul hand calcolution for punching 

 

and i tryed to take the Reduse forces above the column and wall  but still not close to 1.744mpa it was 1.37mpa

 

 

see attachment please 

 

Message 5 of 21
egoze
in reply to: egoze

hellooo

 

good mourning sir

 

would you please tell me why you did not answer my question up to now   🙂 

 

Message 6 of 21
Rafal.Gaweda
in reply to: egoze

It seems you have forgotten that shear force diagram across FE thickness is parabolic
So average value is 2/3 of given by Robot -> 2,93 on map-> 1,953 - close enough to your hand calcs


Rafal Gaweda
Message 7 of 21
egoze
in reply to: Rafal.Gaweda

thank you sir  for reply

sir is this facotre (2/3) i mean working for  corner column and edge as well ?

and why you didnt read 3.27 instead of  2.93 ?

i wish to know please 

 

Again thank in advance 

egoze

Message 8 of 21
Rafal.Gaweda
in reply to: egoze

 

sir is this facotre (2/3) i mean working for  corner column and edge as well ?

 

shearstressdiagram.jpg

 

 

and why you didnt read 3.27 instead of  2.93 ?

 

I took middle value


 



Rafal Gaweda
Message 9 of 21
chrismcc
in reply to: Rafal.Gaweda

2/3 factor applies to rectangular sections.


Sent from Samsung Mobile
Message 10 of 21
egoze
in reply to: Rafal.Gaweda

helooo sir

 

i have done corner column for the same modle ,and i rearange the corner column in slab to conseder it as a corner .as you know sometimes the robot coseder it as an edge column

i have read the stress at the face of column  in robot are was 3.86  and 1.5 mpa

the average (as you said )=2.68 mpa

2/3*2.68=1.78mpa

good for maunual calco=1.86 mpa 

 

my question   WHEN YOU DO CHECK PUNCHING BY THE PROGRAM 

  Q(KN) IS VERY VERY LARGE ?????

YOU CAN SEE THE ATTACHMENTS 

Message 11 of 21
egoze
in reply to: Rafal.Gaweda

**************new

 

hello sir

i have done corner column for the same modle ,and i rearange the corner column in slab to conseder it as a corner .as you know sometimes the robot coseder it as an edge column

i have read the stress at the face of column  in robot are was 3.86  and 2.56 mpa

the average (as you said )=3.21 mpa

2/3*3.21=2.14mpa

 

 for maunual calco

force=205 kn 

m1 =105kn.m

m2=86kn.m

 

b1=b2=c1+d/2=0.5+0.217/2=0.6085

bo=1.217

Jc=0.016

Vu=0.776+0.759+0.622

Vu= 2.159mpa max stress 

 

my question   WHEN YOU DO CHECK PUNCHING BY THE PROGRAM 

  Q(KN) IS VERY VERY LARGE ?????    what is the furmula of Q(KN)   

 

have a look for new pic please

Message 12 of 21
egoze
in reply to: Rafal.Gaweda

and at wich loud combination the program check punching ?

Message 13 of 21
dimogrec
in reply to: egoze

 

egoze perhaps this page will help and also download the verification manual for EU codes from here (dropbox). (If the downloaded file isn't shown properly just add-type    .pdf   after the name of the file)

 

Message 14 of 21
Rafal.Gaweda
in reply to: dimogrec

Good link.

In short : moments are also considered in punching check ; Q and Qadm are calculated reducing set of forces to axial force only (giving the same punching like initial axial force and moments)



Rafal Gaweda
Message 15 of 21
egoze
in reply to: dimogrec

thank you dimogrec

i hope to solve this problem 

i m waiting Mr Rafal for reply 

Message 16 of 21
Rafal.Gaweda
in reply to: egoze

data used for calculations in Robot:

Support no. / Point: S4
V = 205.98 (kN)
Mx = 87.07 (kN*m)
My = -105.58 (kN*m)
A = 0.27 (m2)
gammax = 0.40
gammay = 0.40
Cmaxx = 0.15
Cmaxy = 0.46
Cminx = -0.46
Cminy = -0.15
Jx = 1094456.9 (cm4)
Jy = 1094456.9 (cm4)
betac = 1.00
alfa = 1.00
alfas = 30.00
fi= 0.75
S1 = 6.00
heff = 22.0 (cm)
vlim = 1.25 (MPa)
v = 3.99 (MPa)
A = 0.27 (m2)


Rafal Gaweda
Message 17 of 21
egoze
in reply to: Rafal.Gaweda

Smiley Happy Thank you sir 

 

a small point can i find this (data used for calculations in Robot)  as you did 

for anther columns

 

how can i got this data used for calcolation  

 

Message 18 of 21
Rafal.Gaweda
in reply to: egoze

In 2015 you can not get this data


Rafal Gaweda
Message 19 of 21
egoze
in reply to: Rafal.Gaweda

i have version 2014 and 2015

Message 20 of 21
Rafal.Gaweda
in reply to: egoze

This is all I can tell you right now.



Rafal Gaweda

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Autodesk Design & Make Report