Carichi distribuiti (DL di) sono forze che agiscono su una campata e sono misurate in forza per unità di lunghezza (per esempio. kN/m o kip/ft). Possono essere uniformi o non uniformi.

Applicazione di un carico distribuito

I DL vengono applicati a un membro e per impostazione predefinita si estenderanno sull'intera lunghezza del membro. Gli utenti hanno tuttavia la possibilità di specificare l'inizio e la fine del DL da qualche parte lungo l'intervallo.

I DL applicati ad angolo all'asta possono essere specificati fornendo la X ,E, componenti Z.

Per applicare un DL, vai al menu di input sul lato sinistro e fai clic su Carico distribuito pulsante. Gli utenti possono anche applicare una DL a un membro selezionando prima un membro, quindi fare clic con il pulsante destro del mouse e selezionare “Aggiungi carico distribuito”, che ti porterà al Carico distribuito schermata di immissione con il campo ID membro già compilato.

Quando si applica il DL, gli utenti devono specificare i valori per:

• ID carico distribuito – L'ID numerico utilizzato per identificare ogni DL.
• ID membro – Il membro a cui viene applicato il DL.
• Avvia X-Mag – The starting magnitude of the DL – this can be either in the global X-direction, or the member’s local X direction by changing the axis reference point.
• End X-Mag – The ending magnitude of the DL – this can be either in the global X-direction, or the member’s local X direction by changing the axis reference point.
• Avvia Y-Mag – The starting magnitude of the DL – this can be either in the global Y-direction, or the member’s local Y direction by changing the axis reference point.
• Fine Y-Mag – The ending magnitude of the DL – this can be either in the global Y-direction, or the member’s local Y direction by changing the axis reference point.
• Start Z-Mag – The starting magnitude of the DL in the Z direction – again this can be either Local Z or the member’s Local Z, depending on the Axis setting.
• End Z-Mag – The ending magnitude of the DL in the Z direction – again this can be either Local Z or the member’s Local Z, depending on the Axis setting.
• Start Position – The position along the member where the DL starts. Expressed as a %. Default = 0%
• Finish Position – The position along the member where the DL ends. Expressed as a %. Default = 100%
• Carica gruppo – I carichi possono essere raggruppati con i numeri del gruppo di carico. I gruppi di carico possono quindi essere moltiplicati per un fattore in "Combinazioni di carico’ menù. Opzionale.

Impostazioni avanzate

• Assi – Apply the DL along the global (default) or local axis. If Local, it may help to toggle on the Show Member Local Axis ON in your Visibility Settings, so that users can see the reference axis.

Esempio:

Here’s an example where the distributed load has a -10kN/m Start Y magnitude and a -30kN/m end Y magnitude. Ha anche un file 20% start position and an 80% end position – mostrando che non si estende per l'intera campata del membro, ma piuttosto inizia 20% from the start and end node (1 e 2 rispettivamente).

Local/Global Axes

Global Axis

Here is an example of where member 3 has a 100kN/m distributed load applied to its Globale asse. We can see the force here is applied directly in the global Y (giù).

Asse locale

If we change the axes option to Local we can see that the distributed load has now been applied to the member’s local axis, where local Y is directly perpendicular to the member.

Applying a Non-Linear Distributed Load

Sometimes distributed loads (DLs) on the members of a structure follow a special distribution that cannot be idealized with a single constant one or even a nonuniform linear distributed load, and therefore non-linear distributed loads are needed. For those cases, it is possible to add a distributed load, which distribution is defined by a function in terms of the position along the member.

To apply a non-linear or equation defined DL, vai al menu di input sul lato sinistro e fai clic su Carico distribuito pulsante, then click the Add non-linear distributed load button. Users can also get to that menu by navigating the top bar to modificare > Carichi > Non-linear distributed loads

When applying the non-linear or equation defined DL, gli utenti devono specificare i valori per:

• non è necessario identificare la direzione della campata: Comma separated IDs of the members to apply the non-linear or equation defined distributed load. It is possible to select the members before opening the window, and the input field will populate automatically.
• Load function: Function or equation in terms of the position along the member (X) that defines the load magnitude. The length of the members is normalized, running from 0 per 1.
• Number of loads: Represents the number of linear distributed loads the software will use for approximating the input function.
• Load direction: The same as with uniform and nonuniform distributed loads, the load can be applied in the local or global coordinated system.
• Load group: Name of the group to add the non-linear distributed load that will be created. Per impostazione predefinita, the software will create a new load group, but it is possible to select an existent load group or rename the new one.

After correctly inputting all the required values, the non-linear or equation defined distributed load will be added to the selected members, if the results are not as expected it is always possible to undo the changes and try again. Come menzionato prima, the input function is approximated by a number of linear distributed loads, you can find all of them as regular distributed loads.