How are families of envelopes defined in the descriptive model managed?

Advance Design allows displaying the envelopes of results (displacements, forces, stresses) directly in the analysis model, but other particular envelopes can also be defined directly in the descriptive model.

In this FAQ we will refer only to envelopes defined directly in the descriptive model.

The usability of these envelopes is that for a particular type of maximum result (displacements, forces, stresses) obtained in a certain combination, we can obtain the other concomitant results corresponding to maximum result. These envelopes are interpreted as separate load cases.

To illustrate how to work with envelopes of combinations, we will consider the steel structure in Figure 1, static load cases (Table 1) and their combinations (Table 2).

Figure 1. The analyzed structure

We aim to achieve the maximum effort M_Y from the beams of the analyzed structure and the pair of forces (F_X, F_Z) which are calculated in the combination corresponding to the maximum bending moment (M_Y).

To do this we will choose an envelope of "Concomitant max" type. Figure 2 presents the parameters chosen for these envelopes.

  Note:   The family of envelopes can be created from the "Pilot" - Assumptions section (right-click on "Envelopes" and select "Create a family of envelopes").

Figure 2. Creating the envelope of maximum values for M_Y

Figure 3. The envelope made in descriptive model

After computing the finite element analysis, the family of envelopes appears as an individual load case in the "Analysis - F.E. results" toolbar. Figure 4 presents the forces M_Y, F_X and F_Z for the envelope created in the descriptive model, in the most solicited beams.

Figure 4. Maximum M_Y effort in envelope (left) and the corresponding F_X and F_Z forces