Model a 2D Frame with Robot analysis tutorial

8/10/2019 Model a 2D Frame with Robot analysis tutorial

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Set preferences and structural axes

Learn how to start a new Frame 2D design session and how to set the preferences for regional settingsto Eurocode (Metric). You then learn how to create custom structural axes in the X- and Y-directions asthe basis for your design. Start Autodesk Robot Structural Analysis Professional.

1. In the Opening Screen, click (Frame 2D Design) or select File > New Project… and

click (Frame 2D Design). First, set the preferences to use the Eurocode Regional settingsthat are used throughout this tutorial. Once these preferences have been set they do not changeduring your use of the software unless specifically modified.

2. In the Menu Bar, select Tools > (Preferences…).

3. In the Preferences dialog box, in the Languages area, set the Regional settings to Eurocode, asshown below.

Note: These preferences control this copy of the software. Additional project specific settings can beset in the Job Preference dialog box (Tools > Job Preferences).

You are in the Structural Model layout and can now start the process of developing your structure.The first step is to create a structural axis on which you can build your structure. The axis is only areference and is not linked to the structural members. It is not always required.

4. In the Menu Bar, select Geometry > (Axis Definition).

5. In the Structural Axis dialog box, type a name for the custom axis, such as My Structural Axis.

6. Three different types of axes can be used: Cartesian, Cylindrical, and Arbitrary. In this case, verifythat Cartesian is selected as the type of axis.



7. On the X tab, set the Position to 0.00, No. of repet. to 2, and Distance to 7.5 as shown below.

Note: If the Distance is not displayed as meters (m), close the dialog box, save and close the project,and then open it again. The software should now be working in metric.

8. When you press <Enter> after entering the Distance or click Add, the new positions are added to thelist as shown below. Because these distances were an equal distance apart you could set a repeatand not have to enter each axis position.



9. Switch to the Z tab and set Numbering to Value as shown below.

10. Set the Position to 0.00 and click Add.

11. Add positions for 5 and 5.5 meters. Because these axes are at different distances from each other you need to enter them individually. Additionally, instead of numbers for the labels, the label equalsthe value of the position as shown below.



12.Click Apply and then click Close.

13. The structure axis displays on the grid as shown below.

14. Save the project as My Structural Project.rtd.



Set up bar sections and draw bars

Learn how to set up bars with different sections and then how to draw the structure using those new bars.

In the Menu Bar, select Geometry > (Bars).

1. In the Bars dialog box, the default Bar Type is set to Simple bar and the Section is set to IPE 100 asshown below. For this practice you need to add two other sections.

2. Next to the bar section, click .

3. In the New Section dialog box (as shown below) , you can specify the sections from a variety of databases and families . At the bottom of the dialog box, note that the Section Type is set to Steel.This is the default material that is assigned to new sections. It can be changed to a more specificmaterial later.

4. In the Section selection area, verify that the selected database is Europe and then select IPE in theFamily drop-down menu as shown below.



5. In the Section drop-down menu, select IPE 270 and click Add . Repeat this step and add the IPE330 section.

6. Click Close .

7. In the Bars dialog box, verify that the Section is IPE 330 , and then go to the graphical pane to startdrawing the posts . Move the dialog box out of the way as needed.



Note: You can change the Bar type from Simple bar to a specific type, such as Column or Beam atthis point in the design or after the geometry has been defined.

8. To draw each post, click the first and last corresponding nodes on the structural axis that you definedearlier .

Note: If you are snapping to grid dots rather than to the nodes of the structural axis you can change

the Snap Settings. In the Menu Bar, click Tools > (Snap Settings…). In the Snap Settings dialogbox, turn off the Grid option as shown below.

9. Once you have created the posts , return to the Bars dialog box and set the Section to IPE 270.

10. Draw the ties by clicking the nodes that have been predefined by the structural axis as shown below .



11. In the Bars dialog box, click Close.

12. To display a more realistic visualization of the structure, select View > (Display).

13. In the Display dialog box, select Bars from the list of objects , and then select Section - shape fromthe list of attributes as shown below.

14.Click OK. The more realistic view displays as shown below.



Note: You can also quickly toggle the section shape using (Section Shapes) on the View ControlBar.

15. Save the project.

Model brackets

Learn how to reinforce the structure by modeling additional attributes, such as brackets. In the Menu Bar,

select Geometry > Additional Attributes > (Brackets).

1. In the Brackets dialog box, click (New Bracket).

2. In the New Bracket dialog box, type the Name 0.2 x 1.0 x 1.0 and set the new bracket’s parametersas follows and as shown below.

• Length: 0.2

• Height: 1.00

• Width: 1.00

• Thickness (Th 1): 1.00

• Thickness (Th 2): 1.00

• Position: Down.



Note: The bracket’s position is set relative to the Z-axis.

3. Click Add and then click Close.

4. The new bracket displays in the list of brackets as shown below.



5. To keep track of which bar you are working with, in the View Status Bar, click (Bar Numbers). Thisis an on/off toggle.

6. In the View Control Bar, click (Local Systems) to display the local coordinate system of the bars(as shown below), so that you can verify the bar origins. Brackets are only added to the beginningnode of a bar when you are assigning it in the dialog box.

7. Move the dialog box as needed and place the first bracket on the left side of the structure using eitherof the following methods:

• In the Brackets dialog box, select the Bars edit box and type the bar number where you want thebracket to be attached (in this case, 3 as shown below) and press <Enter> or click Apply. Whenyou use this method the bracket is automatically assigned to the beginning node of the bar.

• In the graphical pane, click the left end of the top left bar. When you use this method you can selecteither end of the bar.

8. Repeat this step to create a bracket on the right side of the structure.

9. Close the Brackets dialog box.


Define supports

Learn how to set a pinned support fixed in the UX- and UZ-directions. In the Standard toolbar, expand the

Layouts drop-down menu and select Supports as shown below or select Geometry > (Supports).



1. In the Supports dialog box, double-click on Pinned (as shown below) to open the Support Definitiondialog box.

2. In the Support Definition dialog box, on the Rigid tab, verify that the Fixed directions UX and UZ areselected as shown below.



3. Click Close.

4. In the Supports dialog box, verify that the pinned option is still selected and click the nodes at thebottom of the structure to apply a pinned support to them as shown below.

Note: Alternatively, you can enter the required nodes numbers in the Current selection field in theSupports dialog box.

5. Save the project as Structure-Project-Loads.rtd.

Apply dead loads

Learn how to define and apply self-weight and uniform loads to the structure. Continue working in your project or open the project Structure-Project-Loads.rtd.

Note: The Tutorial files are located in C:\ProgramData\Autodesk\Examples\Tutorials.

1. In the Standard toolbar, expand the Layouts drop-down menu and select Loads. The layout of the

screen changes to display the design, the Load Types dialog box, and the Loads – Case dialog boxas shown below.



2. In the Load Types dialog box, in the Case description area, set the Nature to dead, and setits Name to G.

3. Click Add. The case is added to the Load Type dialog box and the Loads – Case table. It alsodisplays in the Section toolbar in the Cases drop-down menu as shown below. The current units

display in the right corner of the bottom comment line.



Note: The self-weight load for all of the elements is applied automatically.

4. In the Menu Bar, select Loads > (Load Definition).

5. In the Load Definition dialog box, on the Bar tab, click (Uniform load) as shown below.



6. In the Uniform Load dialog box, in the Values area, in the Z field, type (negative) -1.6 and verify thatthe Coord. System is set to Globalas shown below.

Note: The Z-value corresponds to the total load of the structure (1.6 kN/m). It is set in the globalcoordinate system as a negative value because it is a gravity load.

7. Click Add.



8. Apply the loads as shown below by clicking the bars in the graphical pane. Alternatively, in the LoadDefinition dialog box, in the Apply toarea, enter the bar numbers separated by a space (as shownbelow), and click Apply.

Note: To display the tags for the loads, in the View Control Bar, click (Load Value Descriptions).

You will now use the same method to add a load to the posts.

9. In the Load Definition dialog box, on the Bar tab, click (Uniform Load).

10. In the Uniform Load dialog box, in the Values area, in the Z field, type (negative) -0.6 and verify thatthe Coord. System is set to Global.

11.Click Add.

12. Apply the loads by clicking the posts in the graphical pane. Alternatively, in the Load Definition dialogbox, in the Apply to area, enter the bar numbers separated by a space (in this example, use 1 2), andthen click Apply.

13. The loads are represented on the structure as shown below.



14. Close the Load Definition dialog box.


Apply special loads

Learn how to select the appropriate Design Codes for loads and then how to apply wind and snow loadsto the structure.

Note: For more information on snow and wind loads, please refer to:• EN 1991-1-3 Eurocode: Actions on structures: Part 1-3 Snow loads

• EN 1991-1-3 Eurocode: Actions on structures: Part 1-4 Wind loads

1. To verify that adequate loads codes are available, in the Menu Bar, select Tools > (Job

Preferences).

Note: Job Preferences only control the parameters for the current project.

2. In the Job Preferences dialog box, in the left panel, click the + sign to expand the Design Codes area,and then click Loads. The Code combinations, Snow/wind loads, and Seismic loads for the currentproject are displayed as shown below.



3. Expand the drop-down list of Snow/wind loads and end with EN 1991-1-3/4:2005. Click OK to closethe dialog box.

4. To apply the new loads, in the Menu Bar, select Loads > Wind & Snow > Wind and Snow 2D/3D (as

shown below), or in the Bar Loads toolbar (typically on the right side of the screen) click(Snow/Winds Loads 2D/3D).



5. In the Snow and Wind 2D/3D dialog box, click Auto to select all of the existing nodes, generate anautomatic envelope, and then set the following parameters:

• Total Depth: 30,00 m

• Bay spacing: 5,00 m

• Select Display note after load generation.

6. Click Parameters and note the information in the dialog box. Leave the default parametersunchanged.

7. Click Generate.

8. In the Structure frame selection dialog box, verify that All is selected. This generates wind loads onall of the structure frames.

9. In the Load case list , select Wind R/L. This sets the wind direction from the right to the left as shownbelow.



10.Click OK.

11. Three windows open containing the various calculation notes for the Wind Loads, Results for theWind, and the Structure Dimensions and Wind Data as shown in part below. Calculation notes enableyou to inspect all of the parameters of the loads that have been generated.



12. Close or minimize the notes windows and the Snow and Wind 2D/3D dialog box.

13. All of the loads display in the view window. To display each load case graphically, select a load casein the Cases drop-down list as shown below, or highlight the Cases in the Loads – Case dialog box.

14. When you have finished reviewing the various load cases return to the Load Case G.




Generate load case code combinations

Learn how to generate automatic load case code combinations.

Load case combinations, which are generated automatically, are used to check resistance andserviceability for real situations in which various loads act simultaneously, as defined by a specific code. If required, you can define the action combinations manually, one by one.

1. To verify that the Code combination for your project is correct, select Tools > (Job Preferences).

2. In the Job Preferences dialog box, click the + sign to expand Design codes, and click Loads.

3. Select EN 1990:2002 from the Code combination list.

Note: You can click to edit the code combination regulations.

4. Click OK.

5. To generate the code combinations, select Loads > (Automatic Combinations).

6. In the Load case code combinations dialog box, select Full automatic combinations andclick More>.

7. In the Load Case Code Combination EN 1990:2002 dialog box, select the Relations tab.

8. In the Nature drop-down list you can select each type and create relationships between load cases inspecific groups. By default, theRobot software automatically creates these groups and relationships.

9. Keep the default settings, and click Generate.

Note: You will not see anything happening on the screen at this point.



10. In the Menu Bar, select Analysis > (Calculations) or in the Standard toolbar,

click (Calculations).

11. If a warning message displays, click OK to continue the calculation process.

12. To display the Combinations table, in the Menu Bar, select Loads > Combination Table.

13.

The Definitions of load combinations dialog box opens as shown below.

14. To change how combinations are displayed in the table, right-click on the combinations table, andselect Table columns.

15. In the Combinations dialog box, change the Combination description to Case label and click OK.

16. The new layout of the table displays as shown below.

17. Save the project as Structure-Project-Analysis.rtd.



Run a calculation

Learn how to run calculations on a structural project. Continue working in your project or open theproject Structure-Project-Analysis.rtd.


1. In the Standard toolbar, click (Calculations).

2. The process displays in the Calculations dialog box as shown below. The amount of time requireddepends on the size of the project being analyzed.

Note: If the model was defined properly there should not be any messages. However, if there areproblems with the analysis, the Calculation Messages dialog box opens as shown below. Warningsprompt you to check any suspicious elements (no supports, disconnected part in the model, too weak



elements, too many restrains, etc.). Some of the causes might be intentional and justified, but othersmight result from modeling errors and should be corrected before the analysis is run again.

3. Once the calculation has finished you can analyze the results using various dialog boxes, tables, andgraphic views.


Review results graphically

Learn how to open the Results layout and view the graphical information (diagrams) about the structure,

including the impact of forces, stresses, and reactions. You also learn how to modify the Preferences of the diagrams.

1. In the Standard toolbar, expand the Layouts drop-down menu and select Results and thenselect Results again as shown below.

2. The Results layout opens the Diagrams dialog box and a table of Reactions as shown below.



3. In the Selection toolbar, select the type of case that you want to display. Verify that 1:G (the case thatwas created earlier) is selected.

4. In the Diagrams dialog box, you can specify the information that you want to display, including theinternal forces (NTM), deformation, stresses, reactions, and reinforcement.

5. In the NTM tab, select Fx Force and click Apply. The view displays the forces as shown below.



Note: If you want to modify the size of the diagram components, click the + and – buttons at the

bottom of the dialog box as shown below. By default, the diagrams remain at a constant scale whenyou select different cases. You can also open a new window.

6. Click the + button twice and then click Apply to increase the size of the forces.

7. In the Selection toolbar, change Select Cases to display a different load case diagram.

8. You can check other cases and then return to 1:G for the next steps.

9. The Parameters tab includes settings for the views. In the Diagrams dialog box, hover the cursor overthe arrow near the title to expand the tabs on the side and then select Parameters as shown below.





14. If you have time you can display the other combinations.


View results in table form

Learn how to display the results in a table form and how to filter the table to only display some nodes,bars, and/or cases and to format the table. All tables use the same principles.

1. A large number of tables are included with the software. Because they are so important you canaccess them in a variety of ways, including the Results tab in the Menu Bar, the Tables dialog box(View>Tables…), and the Structural Model Toolbar as shown below.





Note: The table of Reactions automatically displays when you open the Results layout.

2. Click the first several buttons in the toolbar to display the various tables. Note the tools that theycontain and then close all but the Reactions table, which should be at the bottom of the screen.

3. Once a table is open it can be filtered by loads. In the Selection toolbar, expand (NodeSelection) and select Nodes – All.

4. Select the nodes and bars that you want to review. In this case, all Nodes (1to7) and all Bars (1to4)have been selected and Cases has been set to Simple Cases as shown below.

5. To further filter the table information, right-click on the table and select Table Columns…

6. In the Nodal value selection dialog box, you can specify the columns that you want to displayaccording to the type of table. In theReactions tab you can specify the components whoseinformation you want to display as shown below.



7. Move the dialog box as needed to display the Reactions table. Note how the order list is byNode/Case as shown below.

8. Switch to the Load Cases tab. In the Order area, click Case, object.

9. Click OK. The order of the reactions is now listed by Case/Node as shown below.



Note: Once you have set up a table with the required format, you can save the table to a template

that can be used again. In the Menu Bar, select View > Save Table Template. This table view is usedthe next time you open the table.

10. In the Diagrams dialog box, clear all of the parameters to only display the structure.

11. Save the project as Structure-Project-Steel.rtd.

Modify member types

Learn how modify member types to prepare a model for verification.

1. Continue working in your project or open the project Structure-Project-Steel.rtd.


2. In the Standard toolbar, in the Layout drop-down menu, select Steel Design and thenselect Steel/Aluminum Design as shown below.



3. The layout of the screen resets (as shown below) to display dialog boxes for the Definitions andCalculations that are related to the selected code. Having these already open makes the rest of theprocess of structural verification much easier.

Run calculations and review the results

Learn how to run calculations and review the outcome of the steel verification process.

1. In the Calculations dialog box, set the Member verification to 1to4.

2. In the Limit states group of options, verify that Limit states is set to ULS, and then click List on the

same line.

3. In the Load Case Selection dialog box, click None to clear the existing selection.

4. At the bottom of the dialog box, select the Combin. tab and select all of the combinations. (Hold down<Shift> and select the top and bottom of the list.)

5. Click . The load case combinations are added to the Case list as shown below.



6. Click Close.

7. In the Limit states group of options select SLS.

Note: Selecting both ULS and SLS will set the calculations to recognize the correct type of combination and apply the correct checking condition (serviceability or ultimate design).

8. In the Calculations dialog box, click Calculations.

9. The Member Verification dialog box opens displaying the most significant information about thesections. The Messages tab (as shown below), contains important information for the engineer toconsider when taking the next steps in the design.



Note: The Tapered member message is there to remind the engineer that the code does not explainhow to apply verification formulas to tapered members and that the method used by the softwaremight not agree with the expected outcome.

10. The Results tab includes a results interpretation symbol for each section (or section group). In the

case shown below, two of the members passed the test while two of them did not.

11. In the Ratio area, click Analysis to open the Global Analysis – Bars dialog box to review a graphicpresentation of the ratio for the verified members.



12. Close the dialog box.

13. In the Member Verification dialog box, click one of the yellow exclamation marks . The Resultsdialog box opens indicating that there is Instability in the member, as shown in part below.



Note: You can also generate a printable note including the information by clicking Calc Note in thedialog box. Calculation Notes can be saved and printed.

14.Click OK to close the Results dialog box.

15. In the Member Verification dialog box, click Close. You do not need an archive of this attempt.

16.Click Cancel when the Calculation Result Archiving dialog box opens.

Note: The next steps can take engineers hours (or days) to find the right solution depending on thecomplexity of the problem. Some solutions would be to use a tougher steel, to increase the section

diameters, or to change the frame geometry by slightly increasing the beam slope or reducing theframe distance.




Modify bar types

Learn how to change member types and how to create a new member type. In the Definitions dialog box,note that Number 1 is selected and that it is set to the Member type: Simple Bar .

1. Expand the Member type drop-down list and select Column. Change the Name to Column_1 asshown below. Click Save.

2. In the Definitions dialog box, change the Number to 2, Name it Column_2, and change the Member type to Column. Click Save. The beams need to be changed as well, but the standard BeamMember type definition is not appropriate for this situation.

3. In the Structure Definition toolbar, click (Steel/Aluminum Member Type).

4. In the Member Type dialog box, highlight Beam and click (New steel member type definition).

Note: Highlight the Member Type that is most similar to the new type that you want to create so thatsome of the basic properties are automatically applied.

5. In the Member Definition dialog box, in the Member type text box, type Beam_Roof.

6. In the Lateral buckling parameters area, select Lateral buckling.

7. Click Upper flange.

8. In the Lateral Buckling Length Coefficient dialog box, click (Beam) and set the Lcr to 0.2 lo asshown below. Click OK.



9. Repeat this process for Lower flange.

10. The information in the Member Definition dialog box should now look like the example shown below.Click Save and then click Close.



11. The new Member Type is now listed in the Member Type dialog box. Ensure that it is selected, type 34 in the Lines/Bars field as shown below, and click Apply.



12. Close the Member Type dialog box.

13. In the Definitions dialog box, set Number to 3. The Member type is already set to Beam_Roof . Verifythat the Name is set toBeam_Roof_1 and click Save.

14. Change the Name of Member 4 to Beam_Roof_2 if needed, and click Save.


Note: Another way to check and modify member names and types is by using the Start Layout.Select the bars and then change the properties as shown below.




Test the changes and add materials

Learn how to modify the materials of bars and change the bar size of existing members.


Note: You made changes to the bars and need to run the main calculations again.

2. In the Calculations dialog box, click Calculations to run the steel specific calculations. While theprevious steps clarified the types of members, the roof beams are still not strong enough as shownbelow.



You will now make them stronger in two ways. First you will set the material for a section to a higher steel grade and then you will change the size of the section used by the roof beams.

3. In the Structural Definition toolbar, click (Materials) or in the Menu Bar, click Geometry >(Materials…).

4. In the Materials dialog box, expand the Material drop-down list and select S 450.

5. Select IPE 330 (the existing size of the columns) and click Apply. Click Yes when the alert boxdisplays a message saying that you will need to run the calculations again after making this change.The material is replaced as shown below.

6. Close the Materials dialog box.

7. In the Structure Definition toolbar, click (Bar Sections).

8. In the Sections dialog box, select IPE 330.

9. In the Lines/Bars area, type 3 4 and click Apply.The beams change in size.




11. Once the main calculations are done, in the Calculations dialog box, select Calculations to run theMember Verification process again.

12. In the Member Verification dialog box, the structural members now indicate that they are of adequatesize for the structure to withstand its loads.

13. Save and close the project.

Documents

Model a 2D Frame with Robot analysis tutorial