Autodesk Robot Structural Analysis
Hi
I define one moving load in each loading case
mobile dead load G (15 composantes)
mobile snow load S (15 composantes)
mobile wind load W (15 composantes)
After combining Robot gives
G+W : 225 composantes
G+S : 225 composantes
G+S+W : 3375 composantes
This is no sense ! In the moving skylight exemple we need only 15 composantes. How it can be done like it?
Why do you expect 15 combinations?
Calculations as follows:
G+W : 225 composantes = 15*15
G+S : 225 composantes = 15*15
G+S+W : 3375 composantes = 15*15*15
Rafal Gaweda
Product Support
Autodesk, Inc.
Hello,
Thak you to respond!
!
I don't expect 15 combinaisons but I need 15 component cases for each combinaison
The 15 component cases correspond to effective position along the convoy movement
Ok if I have N mobile cranes I will expect 15 to the power of N component. Where N is the number of mobile live loads in the combinaison considered
But in the case of a the moving skylight I have only one convoy. But reaction on the road comes from the wind, the snow, dead load, live load ...
Exemple :
Lenght of road : 14 meters
Road divided each 1 meter
The combinaison of W + LL must have 15 components
Robot considers 15^2=225 components
225-15=210 components cases are not good.
Is it possible to select the component cases to combinate?
Do you know another way to solve such an exemple?
Cordially
Take a look below.
Small example 1 DL , 1 LL ,1 moving load case with 15 components.
In case of manual combinations you should get 15 combinations:
If you generate automatic combinations eg for ULS only (LL acts OR_INCLUDING with moving loads) you will get 94 combinations because of acting \ not acting live loads simultaneusly and differrent factors:
If it is not the case please upload your model \ even simplified just to show me what and how you defined laods, combinations etc
Rafal Gaweda
Product Support
Autodesk, Inc.
Hi,
To avoid misanderstanding I share screenshots
If I use either automatic or manual generation it is the same.
See the following exemple :
I define 3 mobile loads
Mob DL, Mob LL and Mob W
Each is 13 components
In the combination SLS 2, i obtain 169 components (13x13), because SLS 2 refers to 2 moving loads
For instance the component 65 is not in accordance with my design concept
I need only 13 component cases for each combination that comrespond to the alignment of the 3 mobile loads
Is it possible with Robot to select components we want to combinate ??
Is it possible with Robot to define one convoy acting on many cases ??
How to slove the moving skylight exemple??
For now because of delays I am going to use the old design method which consistsin :
- create as many nodes as you want in you beam/road to describe the convoy movement
- create as many loading cases more as you have nodes primary defined
- aplly loads on the nodes
- create manually as many combination more that you defined nodes in the first step
(when I think I have 8 winds to consider with french regulation, it is an hardly job)
Any solution to propose?
Cordially,
Antoine Carimalo
acarimalo wrote:
For instance the component 65 is not in accordance with my design concept
If you look at your screen capture: select component on "Composande du cas" window and use Creer cas... button
Is it possible with Robot to select components we want to combinate ??
See above and at the screen shot below
even if you have manual combinations or manual combination(s) from conversion of moving load combination component
you can select them this way:
Is it possible with Robot to define one convoy acting on many cases ??
If you mean convoy as a set of loads (= vehicle) - of course it is possible
How to slove the moving skylight exemple??
Hope everything what is above helps.
Rafal Gaweda
Product Support
Autodesk, Inc.
Hello,
I was busy on other projects sorry
Acording to your proposition, I still maintain that the "moving load" option can't solve my building concept because :
1- The button "creer cas" create only a virtual case (for visual use only) :
- the create case doesn't appear in the generator of combinations
- if I run a new calculation the virtual create case disappear from everywhere
2- Selecting case components manually among thousands of combinations (stage 2/2 : generator of combinaisons) is not very helpfull.
Finally to solve the problem I use a static analysis model including the static cases during movement : SW DL 2LL 8 W 2 T
I have selected a semi manual option to solve problem of combinations :
- Define the critical position with the help of moving loads as define above (6 positions)
- generate cases for each critical position
- automatic generation for the first position (around 700 combinations)
- export combinations table to excel
- use the excell options "looking for" and "remplace by" to generate the combinations for other positions
- import all combinations in the model (near 4000 combinaision)
Then I have two more models runing in modal analysis correponding to the position "OPENED" and "CLOSED"
Design succeed thanks
Cordially
acarimalo
1- The button "creer cas" create only a virtual case (for visual use only) :
- the create case doesn't appear in the generator of combinations
- if I run a new calculation the virtual create case disappear from everywhere
I guess you mean something different because these cases are not witrual:
Rafal Gaweda
Product Support
Autodesk, Inc.
