This page has been superseded by Chronological sequence in the Android phone, iPhone & iPad volume
Android phone & iPhone
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Chronological Sequence
At a glance: The use of the application to follows a chronological sequence of events is described in the user guide General – Chronological Sequence. A procedure for adopting a stage load and setting up an initial state specific to the Android phone & iPhone is described here.
The chronological sequence
A sequence of computations that follows the chronological sequence of events in the life of a structural member is envisaged. It is also envisaged that such a sequence will be repeated many times as a design progresses from an initial concept to a final perfected design.
Time affects
For the steps to apply a Time Affect Set that includes creep computation see General – Time Affect Sets, Applying a Time Affect Set.
Adopting a stage load
The initial state and stage distortion facilities have a purpose illustrated by two parallel structural members in close association but structurally independent; each having a loading and corresponding distortions. At a particular instant in the construction process these two members are joined so they act as one structural member. Immediately after that instant the resulting member has a loading that is the combined affect of the two loadings before and each component has the same distortion as before that instant.
The procedure described here uses three XSF files; one for each of the contributing members cross-sections, and one for the resulting member cross-section.
The procedure is:
1. For each of the contributing members set up the XSF file including load cases and Time Affect Sets for the chronological sequence before the members are joined. To open a new file tap the “+” button at the top right on the main Files tab. Tap yes on the dialog asking to confirm that the previous file is to be saved.
2. With each of the contributing member XSF files add a Load-case, give it a name indicating its purpose and set it up with the envisaged loading at the instant members are joined. To change the open file tap the name of the desired file in the list on the main Files tab. Tap yes on the dialog asking to confirm that the previous file is to be saved.
3. With each of the contributing members XSF files:
1) Do the computation for the chronological sequence before the members are joined.
2) Compute the load case for the instant the members are joined
3) Make sure the load case for the instant the members are joined is open in the load case editor. If it is not tap its name in the list on the main Load cases tab. This should open the editor for it.
4) Tap the button “Adopt this load case as at a stage’. This button is on the first display of the editor. Tap yes on the confirm dialog.
5) When changing the open file tap yes on the dialog to confirm that the previous open file is to be saved.
4. Open the file for the resulting member cross-section.
5. Delete all the components and all the materials that remain from a previous cycle of the design process. The Load-cases from the previous cycle should remain and can be used again.
6. For each of the contributing members (with the resulting member file open):
1) On the main Components tab tap the button “Import component from another XSF file”. A display headed Import Source should appear with a list of files. If an error dialog appears about a file having a different unit system tap OK. This relates to a default selection and is irrelevant.
2) On this Import Source file list tap the name of the contributing member file. A note appears below the list indicating it is selected and also a next > button at the top right becomes enabled.
3) Tap the next > button. A display headed “Components to import” with a list of component names appears.
4) Tap on each component name in that list. Each tap will remove the component name from the list. This is in accordance with the explanation in iPhone – Introduction, Files, Other Files.
5) Tap the back< button in the top left. The display should return to the Import Source file list. For the second contributing member XSF files repeat from step 2) above.
This procedure sets up the initial state of the resulting member.
A further step is a check and also illustrates the meaning of this. Use a load case to do a computation with the “Utility: Curvatures and one strain” method with all three distortion variables set to zero. This should result in a loading that is the combined affect of the loadings on the contributing members.
Facilities to zero the stage and other distortions
If the chronological sequence starts before any concrete is cast or pretension tendons are tensioned all the stage distortions and other distortions should be set to zero at the beginning of each cycle.
The main Load cases tab display has a button “Zero all stage distortions” and the main Time affects set tab display has a button “Zero all other distortions” intended for this.
The aging of concrete
The stress/strain relationship of concrete changes as the concrete ages. A sequence of xsf files could be set up that each have a set of material descriptions appropriate to different points in the chronology.
The main Materials tab has a button “Import material from another XSF file” that leads to a panel headed “Import Source” with a list of files.
On a phone when a file is selected that panel has a button “Overwrite all materials” intended for this purpose.
On an iPad the selection of a file from that list causes a change to a panel headed “Materials to overwrite” and that panel has a “Overwrite all materials” button intended for this purpose.