How to model stacked beams using Rigid Links
Simply specify the member “Τύπος” όπως και “Άκαμπτος σύνδεσμος” to create a member that acts as a Rigid Link. When this is done you will see that the rigid link is drawn with a light-grey color and has an “Ρ” σύμβολο δίπλα του:
Οι άκαμπτοι σύνδεσμοι μπορούν να είναι χρήσιμοι για τον καθορισμό άκαμπτων συνδέσεων μεταξύ δομών που περιλαμβάνουν στοιβαγμένες δοκούς ή μέλη. They are often thought of as imaginary stiff links that join members so they can translate and/or rotate together. Ένας άκαμπτος σύνδεσμος μπορεί επίσης να χρησιμοποιηθεί για τον χειροκίνητο έλεγχο για τις αντισταθμίσεις μελών. Επιπροσθέτως, μπορείτε να αλλάξετε την σταθερότητα / απελευθερώσεις στον άκαμπτο σύνδεσμο για να ελέγξετε ποιες δυνάμεις και επιπτώσεις έχει σε αυτό που συνδέεται.
Looking at the analysis results, you can see that as the top beam is loaded, and deflects, so does the beam below:
Member design checks will still run, ωστόσο, it is important to consider the limitations of the software in understanding the unbraced lengths and member end fixities. In this scenario, the Lb should be adjusted according to your design needs.
Μέθοδος 2: Using Custom Shapes in Section Builder
An alternative method to the above is using the SkyCiv Section Builder to model two models on top of each other, and treating it as one element:
This will use FEA to calculate the geometric properties of this ‘single’ Ενότητα. It will then use those geometric properties along with the entire line element. More on this method can be viewed on the following documentation page: Composite and Built-up Shapes in SkyCiv
Σύγκριση αποτελεσμάτων
When modeling the two methods together, the results are quite consistent for deflection:
Since the members are only linked at certain points along the beam, there is a variance in the connectivity of the beams. In the bottom (Section Builder Method), the element is treated as one piece, whereas in the Rigid Link method, it is only connected at 3 points along the beam’s span.
