CYPE Connect

Generate from the BIM model

Clicking on the “Generate from the BIM model” option opens the “Read the loadcases from BIM model” window, which contains three sections: “Stress/Strain”, “Capacity design” and “Rotational stiffness”.

Stress / Strain

In the "Stress/Strain" section, the program can filter the load combinations to be imported from the BIM model for this calculation. Not all load combinations have significant values; therefore, it may be advisable to filter the number of combinations to be imported in order to reduce the calculation time.

To do this, filters are entered one by one into a table with the columns "Force", "Condition" and "Percentage".

By default, a filter is provided for each of the six types of "Force": axial (“N maximum”), shear forces in the Y and Z directions (“Vy maximum”, “Vz maximum”), and moments in the X, Y and Z directions (“Mx maximum”, “My maximum”, “Mz maximum”).

For each type of force, the combinations in which that particular force satisfies the selected "Condition" ("Greater than", "Greater than or equal to", "Less than" or "Less than or equal to") in relation to the specified "Percentage" of the maximum value, for both positive and negative values.

For example, you can specify the condition that the force must be "Greater than or equal to" 90 per cent of the maximum stress. This prevents loadcases with low force values from being imported.

In addition to filtering by percentage of effort, you can set a minimum value to determine whether or not to include the combinations by entering an "Absolute minimum value for forces" and an "Absolute minimum value for moments" in the boxes at the bottom of this section.

Design by capacity

In the "Capacity design" section, you can tick the relevant box to "Select the seismic loadcases to perform the analysis with capacity design criteria".

The program will therefore identify loadcases of this type and automatically tick the "Capacity design" box for them in the list of loadcases.

Rotational stiffness

The "Generate from BIM model" option can also be used to import loads for rotational stiffness analysis. In addition to the loads, the elastic lengths of the bars in the structural model are also imported; these lengths are required for the correct classification of the connection.

From the drop-down menu in the "Rotational stiffness" section, select one of the following five options to import the loadcases based on the internal forces:

• Maximum moments, with simultaneous forces
  Enter the loadcases with the highest moments "My" or "Mz", with a positive or negative sign, as well as the other associated stresses.
• Maximum moments, without the other forces
  For loadcases involving peak moments, only the values of "My" and "Mz" are relevant.
• Maximum moments per plane, with their corresponding
  forces
  Import the loadcases corresponding to the maximum bending moments, together with their associated force components, by plane (i.e. the XY and XZ planes).
• All
  Import all loadcases.
• None
  Does not import any loadcases.

Loadcases

The window that appears when you click this option is used to define the loadcases that can be taken into account in the connection analysis.

Generating or entering loadcases

Loadcases may have been generated automatically using the "Generate from the BIM model" option (1), located on the top toolbar of the "Analysis" tab interface.

You can also edit or enter them manually. In that case, you use the buttons at the top of the table (2), which allow you to "Add", "Copy", "Delete" and move loadcases within the list.

Finally, if the connection includes timber sections, the "Condition" and "Duration" for each loadcase are also selected from the relevant drop-down menus.

Loads

The "Loads" option is used to define the loads applied to the bars in the connection for each loadcase.

The loads may have been generated automatically using the "Generate from BIM model" option.

You can edit them or enter them manually. In that case, select each of the "Bars" in the table on the left, which shows their "Reference", as well as the "Load-bearing" and/or "Rotational stiffness" columns, where applicable.

Selecting load-bearing beams

In the connection analysis model, you must define one or more bars of the connection as "Load-bearing" by ticking the corresponding box in the column of the same name, unless an baseplate has been defined (in these connections, no bars may be designated as load-bearing, and this column will not be displayed).

The remaining bars are connected to this component, to which the loads are applied.

Each load-bearing beam has an external connection at one end. If the load-bearing bar is continuous or runs through the connection, you must specify whether there is an "External connection" "At both ends", "At the start end" or "At the final end" of the section by selecting one of the options from the drop-down menu that will appear in the centre of the dialog box.

The program displays a message stating that "The forces do not need to be entered into the load-bearing section, as they are determined by equilibrium".

Selecting the design model

Each non-load-bearing bar includes the "Design model" drop-down menu, which allows you to select different load and constraint configurations, better suited to various structural situations. You must select one of the following options:

• N – Vy – Vz – Mx – My – Mz
  This is the default model. The end of the beam has no external connections, allowing the six internal forces to be defined: the axial force, the shear forces in the Y and Z directions, and the moments in the X, Y and Z directions.
• N - Vy - Mz
  This model allows loads to be defined in the XY plane. The end of the beam is constrained against displacement along the z-axis and rotation about the y-axis. The axial force, the shear force in the Y-direction and the moment in the Z-direction are defined.
• N - Vz - My
  This model allows loads to be defined in the XZ plane. The end of the beam is constrained against displacement along the y-axis and rotation about the z-axis. The axial force, the shear force in the Z-direction and the moment in the Y-direction are defined.
• N - Vy - Vz
  In this model, the end of the bar has its rotational degrees of freedom restrained, while no moments can be applied. The axial force and the shear forces in the Y and Z directions are defined.

In the central part of the dialog box, below this drop-down menu, there are two tabs for defining the load or force tables in the units specified for each "Loadcase" (indicating whether it is "Acting" or not). Right-clicking on the cells brings up additional tools that allow you to copy and paste data directly from spreadsheets.

In the design model, the program will apply loads at the end of each section to calculate the forces entered by the user at the specified point.

"Stress/Strain, Buckling" tab

In the "Stress/Strain, Buckling" tab, the loads or "Forces at the end of the bar" are defined for each load case to carry out these analyses (and the "Forces towards the origin of the bar" if the bar is continuous or passes through the connection), by entering their values in the cells of the central table.

In the field below each internal force table, you can also enter the “Distance between the point of application of the forces and the theoretical node”. This allows you to specify where the forces are being defined on each bar:

• If the forces at the theoretical node – that is, the point where the section axes intersect – are being entered, the distance value must be zero.
• If you wish to input forces from another point – for example, those acting on the face of a column – you must enter a distance value equal to half the width of that column.

This distance will also be read from the BIM model, provided that the structure has been analysed considering the finite dimensions of the connections.

'Rotational Stiffness' tab

In the "Bars" browser on the left, you can also select the bars for which you wish to calculate the rotational stiffness of the connection by ticking the "Rotational stiffness" box in the relevant column.

The "Rotational stiffness" tab requires a list of loads or "Forces" for each loadcase, which can be entered into the cells in the central table.

In addition, at the bottom, you must enter the lengths of the elastic bar in the structural model (used to determine the limit stiffnesses of rigid or hinged connections) and the k_b factor:

• Theoretical length of the elastic rod (Y)
• Theoretical length of the elastic rod (Z)
• With a "kb" factor specific to this bar (optional)

The diagram, which can be accessed via the help button at the bottom, shows how the connection is ‘classified’ as "Rigid" (1), "Semi-rigid" (2) or "Hinged" (3) in the M-Φ plane, based on the definition of the "Limit rotational stiffness for rigid connections", Sj1=kbEIb/Lb, and the "Limit rotational stiffness for pinned connections", Sj3=k'bEIb/Lb.

Editing forces

The "Edit forces – Selected loadcase" tool, which is common to both tabs, allows you to define the forces applied to each bar based on its mechanical properties:

• The "N" axis is defined by entering a coefficient that multiplies the product A·fy.
• The "V_y" cutting factor is defined by entering a coefficient that multiplies the product A_vy·fy.
• The "Vz" shear force is defined by entering a coefficient that multiplies the product A_vz·fy.
• The "M_y" moment is defined by entering a coefficient that multiplies the product W_el,y·fy, or alternatively Wpl_,y·fy.
• The "Mz" moment is defined by entering a coefficient that multiplies the product W_el,z·fy, or alternatively Wpl_,z·fy.
• On the right, the values of the mechanical properties A, A_vy, A_vz, W_el,y, Wpl_,y, W_el,z, Wpl_,z and f_y for the bar are shown.

For example, this feature makes it easier to design connections with a higher strength than that of the joined bars – a common requirement in various seismic design codes.

3D view

In the "3D view" on the right-hand side of the dialog box, the loads applied to each bar in the connection are displayed graphically according to the selected loadcase.

The theoretical node and the point at which the forces are applied are also shown as a yellow cube, cylinder or sphere (depending on the calculation model chosen).

In addition, the help button in the top right-hand corner opens a diagram showing the “Axis criteria for continuous sections” and the “Axis criteria for non-continuous sections” (which allows you to determine the direction and sense of the forces applied with a positive sign), as well as the parameters relating to the ‘Rotational stiffness’ analysis (Ly and Lz).

To apply the changes, click “Accept”.

Design options

This tool allows you to configure the “Design options”.

Firstly, in the "Discretisation" section, enter the "Maximum element size". This value refers to the side length of the triangular finite elements used by the program to discretise the sections and plates. Using a value between 30 and 50 millimetres yields good results with reasonable calculation times.

Next, in the "Welds" section, you can adjust the "Length for calculating average stresses". Stress concentrations typically occur at the ends of the weld bead, where the values are usually higher than elsewhere. If this is the case, increasing the length reduces the average stress.

In the “Buckling” section, you can select the “Number of buckling modes” to be calculated in this analysis. The buckling analysis can be carried out using the same loads as the "Stress/Strain" analysis or using a different set of loads. This can be controlled by ticking or unticking the "Perform the instability analysis with the same loads as the Stress/Strain analysis". If this option is enabled, the “Buckling” tab will appear in the “Loads” dialogue box, where you can enter the internal forces specifically for this calculation.

In the "Multiprocessing" section, you can configure the "Analysis method" used by the program to determine the maximum number of OpenSees© engine instances to be used to carry out the analysis. The "Automatic" method aims to make the most of the computer’s capacity by launching as many instances as possible, whilst if "Sequential" is selected, you must enter the "Maximum number of OpenSees© instances". Further information on these methods can be found by clicking on the help button on the right-hand side.

To confirm the changes, click on "Accept".

Stress / Strain

The "Stress/Strain" option allows you to carry out the stress analysis and verify the connection elements.

The first time the analysis is run, the deployed version of OpenSees© is automatically installed. If it is already installed, the analysis is carried out. If multiple processors are available, the program can analyse several loadcases simultaneously.

Once you have finished, you can view the results provided by the program to continue your work.

Maximum demand capacity ratio

If "Maximum demand capacity ratio" is selected, in the 3D view of the connection on the left-hand side of the window, each element is displayed in a colour corresponding to its demand capacity ratio.

A colour scale is displayed at the bottom of the 3D view of the connection to aid interpretation

The following results are also displayed on the right-hand side of the window when you select "Stress / Strain" from the drop-down menu:

Maximum demand capacity ratios

At the top of the right-hand side there is a table (1) showing the "→ Maximum demand capacity ratios" of the components for each "Type", including "Sections", "Plates", "Bolts" and "Welds".

Each of them shows the maximum "Demand capacity ratio" percentage and specifies the "Loadcase" and "Verification" to which it corresponds.

Checks

Below this is the "Checks" table (2) for each connection component, based on the various criteria set out in the standards selected by the user. If desired, the "Only show the failed checks" box can be ticked.

Here, for each "Element" in the connection, the "Demand capacity ratio" percentage is shown in the corresponding "Check".

The results displayed on the screen and on the side panel are coordinated as follows:

• If you click on a connection element in the viewport, the table will display only the checks for the selected element.
• If you click on an empty space in the 3D view, the checks for all the elements in the connection are displayed.

Furthermore, when you select an element "Type" in the "Maximum loads" table, the program selects the corresponding element in the "Checks" table.

Detailed check report

When you click on any check, the program displays a detailed report of that check (3) in the bottom right-hand corner, showing the relevant section of the regulations and the parameters involved in its verification.

This information can be "Shared" or "Exported" in various formats or printed directly from the "Preview".

Von Mises stress

By selecting the relevant option from the "Result" drop-down menu on the top toolbar, you can also view the "Von Mises stress" for the selected "Loadcase"

As a result, in the connection view, the contour plot of the selected von Mises stress and the element discretisation are displayed.

You can also click on any sheet to bring up a pop-up window showing the "Component mesh" and the results for that specific sheet.

Equivalent Von Mises deformation

The next result that can be selected is the contour plots for the "Equivalent Von Mises deformation".

Once again, for each "Loadcase", the program plots the percentage values of the deformation using contour plots.

Displacements

Finally, the "Displacements" values for the connection elements can be displayed via their representation in the 3D view by selecting the relevant "Loadcase".

You can apply a "Scale" to the displacements by entering a value in the relevant field in the "Results" group on the top toolbar to improve their display.

Display options

To the right of the "Results" drop-down menu, you can configure the "Display options" to adjust the result views by contour plots:

• The "Contour plot representation" can be "Discrete" if you want the program to use a finite colour scale, or “Continuous” if you want it to use a gradient.
• The "Show mesh" option is also included, which allows you to show or hide the finite element mesh by toggling it on or off.
• In addition, "Limit values" can be specified for the display of results by adjusting both the "Minimum value" and the "Maximum value" of the scale.

Rotational stiffness

The "Rotational stiffness" option carries out the rotational stiffness analysis. This design option allows you to determine the moment capacity, initial stiffness, secant stiffness and connection classification (rigid, semi-rigid or pinned) of steel sections.

To obtain the moment-rotation diagram, the program carries out an iterative process, calculating the rotation at different load steps. The resisting moment is obtained when any component of the connection (plates, sections, welds or bolts) fails, i.e. when its demand capacity ratio exceeds 100 per cent.

Once you have finished, you can view the results provided by the program to continue your work.

The results of the rotational stiffness analysis are displayed on the right-hand side of the "Analysis" tab, within the connection editor.

From the drop-down menu at the top, you can select the type of results to be displayed. When you select "Rotational stiffness" from this drop-down menu, the program displays two tables and the moment-rotation diagram:

"Sections" table

The first table shows all the analysed bars with their "Reference", "Plane", "Length", secant stiffness ("Sj"), the limit rotational stiffness for rigid connections ("S,j1"), the limit rotational stiffness for pinned connections ("Sj,3") and the classification of the connection in each plane ("Rigid", "Semi-rigid" or "Pinned").

To classify a connection as rigid, semi-rigid or hinged, the limit stiffness values for rigid and hinged connections must first be established. Depending on the selected steel standard, either the initial stiffness or the secant stiffness will be compared with these limits.

"Loadcases" table

This table shows the load cases calculated for the selected member. Each load case indicates the applied moment ("M"), the resisting moment ("Mr"), the secant stiffness ("Sj") and the initial stiffness ("Sj,i").

Moment-rotation (M-Φ) graph

The graph shows the moment-rotation curve, the applied moment for the selected loadcase (M), the resisting moment (Mr), the secant stiffness (Sj), the limit stiffness for rigid connections (Sj,1) and the limit stiffness for hinged connections (Sj,3).

The diagram, which can be accessed via the help button in the top right-hand corner, shows the "Classification" of the connection as "Rigid" (1), "Semi-rigid" (2) or "Hinged" (3) in the M-Φ plane, based on the definition of the "Limit rotational stiffness for rigid joints", Sj1=kbEIb/Lb, and the "Limit rotational stiffness for hinged joints", Sj3=k'bEIb/Lb.

Deformation

The viewport on the left displays the deformation and contour plots for the selected loadcase and buckling mode, using a colour code, as well as the discretisation of the connection elements.

Critical load factors

In the right-hand panel, selecting "Buckling" from the drop-down menu displays a table showing the "Buckling mode(s)" for each "Loadcase" and their corresponding "Critical load factors".

Clicking on each mode in the table will display the corresponding deformation in the viewer.

Display options

To the right of the "Result" drop-down menu, you can configure the "Display options" to adjust the result views by contour plots:

• The "Contour plot representation" can be "Discrete", if you want the program to use a finite colour scale, or "Continuous" if you want it to use a gradient.
• The "Show discretisation" option is also included, which allows you to show or hide the finite element mesh by toggling it on or off.
• In addition, "Limit values" can be specified for the display of results by adjusting both the "Minimum value" and the "Maximum value" of the scale.

Reports

In the connection report, under the "Buckling" section, there is a table showing the number of buckling modes calculated for each loadcase, as well as the critical load factors associated with each of them.