#### Further Information

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• ### In RF-/DYNAM PRO - Forced Vibrations, why does my time diagram function formula output incorrect values which appear to be off by only a factor?

New FAQ 004342 EN

In the Dlubal programs, all values are stored internally based on SI units.  When a user changes the units in the program to metric or imperial, SI units are still used internally and only the value displayed in the interface is modified.  Therefore, all values set in the time diagram function also default to SI units unless the user clarifies an alternative unit.

Let's look at a simple example shown in Figure 1 where the parameter x = 1 ft has been set in RFEM.

In RF-DYNAM PRO - Forced Vibrations, the time diagram function is defined as k(t) = 1*x where 1 is the multiplier (1/ft) to convert x to a dimensionless value.  You can see in Figure 2, because all values default to SI units, the Multiplier column produces values of 0.305 instead of the correct value of 1.000.

In order to correct the issue, the user only needs to specify the units of the multiplier as (1/ft) in the function equation.  This can be done with the formula modification k(t) = 1/1[ft]*x as shown in Figure 3.  Notice the Multiplier column now shows the correct values of 1.000.

In summary, when using units in the program other than SI units, coefficients or multipliers in the time diagram function should be accompanied with alternative units defined in brackets.

• ### Where can I set the Poisson's ratio?

New FAQ 004341 EN

The Poisson's ratio is set under the material by using the Edit Material dialog box.
• ### When displaying the result diagrams on a member (the "rib" type), there is the option to display the internal force VL. What is this value and how is it calculated?

New FAQ 004340 EN

The force VL is the longitudinal shear force between the top surface and the member. It is calculated as an integrated shear flow between the plate and the member at a particular point on the member.

For the simplified example provided here, the resulting cross-section values for the integration width of 10 cm are as follows:

• $I_y=\frac{b\times h^3}{12}=\frac{10 cm\times20 cm^3}{12}=6,666.67 cm^4$
• $S_y=h_1\times b\times((h-e_z)-\frac{h_2}2)=10 cm\times10 cm\times((20 cm-10 cm)-\frac{10 cm}2)=500 cm^3$
• $\tau=V_L=\frac{V_z\times S_y}{I_y\times b}=\frac{5.53 kN\times500 cm^3}{6,666.67 cm^4}=0.415 kN/cm=41.5 kN/m$
The integration width has been set to the total of 10 cm.

Values:
• Iy second moment of area
• Sy statical moment
• h1 height of the upper cross-section part
• h2 height of the lower cross-section part
• ez centroidal distance
• h total height
The values can be adjusted for a T-beam.
• ### What does CS271) ... or ST320) ... mean, or how can I create a connection to the standard?

New FAQ 004339 EN

The Design According to Formula column lists the equations of the standard used to carry out the design.

The abbreviations stand for the following designs:

CS Cross-section design
ST Stability analysis
SE Serviceability (SLS design)

The numbers directly behind it are internal information.

The lower table of the intermediate values shows the design formulas with the design conditions that are relevant for the selected design.
• ### When trying to perform a calculation, I get the message 'The path to the RWIND Simulation working directory must not contain any non-ASCII characters.' What can I do?

New FAQ 004338 EN

The working directory is a local path where the data of the currently opened structure is temporarily handled and saved. It is created with the first letters of the file. Only ASCII characters may be used.

Non-ASCII characters include e.g. 'ä', 'ö', and 'ß'.

To avoid this problem, special characters in the file name should be replaced by ASCII characters, for example, 'ae' and 'ss' instead of 'ä' and 'ß'. After opening the file again, the message no longer appears.
• ### How can I only calculate very specific load cases, load combinations, or result combinations with the help of a command with the COM interface?

New FAQ 004337 EN

To calculate only certain load cases, load combinations, or result combinations, just like the "To Calculate ..." command (see Figure 01), you can use the CalculateBatch method of the ICalculation interface. When transferring data, the method expects a field with the loading type. Loading includes the number of the loading and the type (e.g. load combination):

Sub batch_test ()    '   get interface from the opened model and lock the licence/program    Dim iModel As RFEM5.IModel3    Set iModel = GetObject(, "RFEM5.Model")    iModel.GetApplication.LockLicense    On Error GoTo e    'get interface for calculationDim iCalc As ICalculation2    Set iCalc = iModel.GetCalculation    'create array with loading typesDim loadings (3) As Loadingloadings (0) .no = 1loadings (0) .Type = LoadCaseType    loadings (1) .no = 4loadings (1) .Type = LoadCaseType    loadings (2) .no = 4loadings (2) .Type = LoadCombinationType    'calculate all loadings from the array at onceiCalc.CalculateBatch loadingse: If Err.Number <> 0 Then MsgBox Err.description,, Err.Source        Set iModelData = Nothing    iModel.GetApplication.UnlockLicense    Set iModel = NothingEnd Sub
• ### How can I check the generated load combinations for the different design situations in CRANEWAY?

New FAQ 004336 EN

In the CRANEWAY program, you can select the display of load combinations for the individual design situations in Window 1.5 Load Combinations in the middle.
• ### RFEM shows a warning message about an intersection that is not defined correctly. How can I avoid this?

New FAQ 004335 EN

The reason for this warning might be overlapping surfaces, which can occur when for example one solid is modeled onto another, see figure 1.

In order to avoid overlapping surfaces, an opening is required here. After defining that opening, also check if the definition of the solids have to be corrected.

• ### Where can I highlight the locations with the maximum and minimum surface pressures on the model in RWIND Simulation?

New FAQ 004334 EN

The program provides the "Min/Max Values" option in the Display Navigator under the "Scalar Fields" branch. When this option is activated, the program displays for the result types

in the graphic, one result bubble at the location with the smallest and the largest globally occurring result.

• ### In RWIND Simulation, I want to rotate the model, adjust the wind tunnel, and then rotate the model again. How can I prevent the rotation point of the model from being changed?

New FAQ 004332 EN

In RWIND Simulation, it is possible to adjust the model position and the model rotation manually. To do this, simply select Model → Edit in the navigator and then the desired rotation angle in the Position tab. In this case, the rotation is carried out without changing a displacement.

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If not, contact us via our free e-mail, chat, or forum support, or send us your question via the online form.

#### First Steps

We provide hints and tips to help you get started with the main programs RFEM and RSTAB.

#### Wind Simulation & Wind Load Generation

With the stand-alone program RWIND Simulation, wind flows around simple or complex structures can be simulated by means of a digital wind tunnel.

The generated wind loads acting on these objects can be imported to RFEM or RSTAB.

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