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Answer
The working directory is a local path where the data of the currently opened structure is temporarily handled and saved. It consists of the first letters of the file. Only ASCII characters may be used.The nonASCII characters are, for example, "ä," "ö," and "ß."To avoid this problem, replace the special characters in the file name by the ASCII characters, such as "ae" and "ss" instead of "ä" and "ß." When you open the file again, the message will no longer appear. 
Answer
In order to only calculate specific load cases, load combinations, or result combinations in the same way as the "To Calculate..." command (see Figure 01), you can use the CalculateBatch method of the ICalculation interface. For the transfer, the method expects a field with the load type of Loading. This Loading includes the number of the load, and the type (for example, a load combination):
Sub batch_test()' get interface from the opened model and lock the licence/programDim iModel As RFEM5.IModel3Set iModel = GetObject(, "RFEM5.Model")iModel.GetApplication.LockLicenseOn Error GoTo e' get interface for calculationDim iCalc As ICalculation2Set iCalc = iModel.GetCalculation' create array with loading typesDim loadings(3) As Loadingloadings(0).no = 1loadings(0).Type = LoadCaseTypeloadings(1).no = 4loadings(1).Type = LoadCaseTypeloadings(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.SourceSet iModelData = NothingiModel.GetApplication.UnlockLicenseSet iModel = NothingEnd Sub 
Does the RF‑LAMINATE program consider the shear correction factor for crosslaminated timber plates?
Answer
The shear correction factor is considered in the RF‑LAMINATE addon module by using the following equation.
$k_{z}=\frac{{\displaystyle\sum_i}G_{xz,i}A_i}{\left(\int_{h/2}^{h/2}E_x(z)z^2\operatorname dz\right)^2}\int_{h/2}^{h/2}\frac{\left(\int_z^{h/2}E_x(z)zd\overline z\right)^2}{G_{xz}(z)}\operatorname dz$with $\int_{h/2}^{h/2}E_x(z)z^2\operatorname dz=EI_{,net}$The calculation of shear stiffness can be found in the English version of the RFLAMINATE manual, page 15 ff.For a plate with the thickness of 10 cm in Figure 01, the calculation of the shear correction factor is shown. The equations used here are only valid for simplified symmetrical plate structures!Layer z_min z_max E_x(z)(N/mm²) G_xz(z)(N/mm²) 1 50 30 11,000 690 2 30 10 300 50 3 10 10 11,000 690 4 10 30 300 50 5 30 50 11,000 690 $\sum_iG_{xz,i}A_i=3\times0.02\times690+2\times0.02\times50=43.4N$$EI_{,net}=\sum_{i=1}^nE_{i;x}\frac{\mbox{$z$}_{i,max}^3\mbox{$z$}_{i,min}^3}3$$=11,000\left(\frac{30^3}3+\frac{50^3}3\right)+300\left(\frac{10^3}3+\frac{30^3}3\right)$$+11,000\left(\frac{10^3}3+\frac{10^3}3\right)+300\left(\frac{30^3}3\frac{10^3}3\right)+11,000\left(\frac{50^3}3\frac{30^3}3\right)$$=731.2\times10^6 Nmm$$\int_{h/2}^{h/2}\frac{\left(\int_z^{h/2}E_x(z)zd\overline z\right)^2}{G_{xz}(z)}\operatorname dz=\sum_{i=1}^n\frac1{G_{i;xz}}\left(χ_i^2(z_{i,max}z_{i,min})\;χ_iE_{i,x}\frac{z_{i,max}^3z_{i,min}^3}3+E_{i,x}^2\frac{z_{i,max}^5z_{i,min}^5}{20}\right)$$χ_i=E_{i;x}\frac{z_{i,max}^2}2+\sum_{k=i+1}^nE_{k;x}\frac{z_{k,max}^2z_{k,min}^2}2$χ_{1} 13.75 10^{6} χ_{2} 8.935 10^{6} χ_{3} 9.47 10^{6} χ_{4} 8.935 10^{6} χ_{5} 13.75 10^{6} $\sum_{i=1}^n\frac1{G_{i;yz}}\left(χ_i^2(z_{i,max}z_{i,min})χ_iE_{i,y}\frac{z_{i,max}^3z_{i,min}^3}3+{E^2}_{i,y}\frac{z_{i,max}^5z_{i,min}^5}{20}\right)=$
8.4642 10^{11} 3.147 10^{13} 2.5 10^{12} 3.147 10^{13} 8.4642 10^{11} Total 6.7133 x 10^{13}$k_z=\frac{43.4}{{(731.2e^6)}^2}6.713284\;e^{13}=5.449\;e^{3}$$D_{44}=\frac{{\displaystyle\sum_i}G_{xz,i}A_i}{k_z}=\frac{43.4}{5.449\;e^{3}}=7,964.7 N/mm$This corresponds to the resulting value in RF‑LAMINATE (Figure 02). 
Answer
In RF‑GLASS, there are two different types of calculations. On the one hand, there is the "2D" calculation. In this case, a glass structure is displayed as a surface element. When considering the shear coupling, the program determines an equivalent crosssection by using the laminate theory On the other hand, there is the "3D" calculation. In this case, the composition is modeled as a solid element in the calculation, and thus the effectiveness of stiffnesses between the foil and glass is determined exactly when considering the coupling.
Further information about the calculation methods can be found in the RF‑GLASS manual, Chapter 2.

Answer
Only the default setting of 1 load increment can be set when a complex nonlinear material model is defined. The reason for this is because the program cannot determine the correct material stiffness for each incremental loading amount. The exact maximum load needs to be applied to the structure in order to determine the state of the material's stress/strain diagram.
Figure 01  Material Model  Nonlinear material definedThis setting can be found and changed under "Calculation Parameters" as well as under the "Calculation Parameters" in the load cases and combinations dialog box. 
Answer
The following code shows how to get different calculation parameters via the COM interface. It also demonstrates how to specify a setting for deactivating shear stiffness:' get model interfaceSet iApp = iModel.GetApplication()iApp.LockLicense' get calculation interfaceDim iCalc As RFEM5.ICalculation2Set iCalc = iModel.GetCalculation' get surface bending theoryDim calc_bend As RFEM5.BendingTheoryTypecalc_bend = iCalc.GetBendingTheory' get settings for nonlinearitiesDim calc_nl As RFEM5.CalculationNonlinearitiescalc_nl = iCalc.GetNonlinearities' get precision and tolerance settingsDim calc_prec As RFEM5.PrecisionAndTolerancecalc_prec = iCalc.GetPrecisionAndTolerance' get calculation settingsDim calc_sets As RFEM5.CalculationSettingscalc_sets = iCalc.GetSettings'get calculate optionsDim calc_opts As RFEM5.CalculationOptionscalc_opts = iCalc.GetOptions' set ShearStiffness to falsecalc_opts.ShearStiffness = FalseiCalc.SetOptions calc_optsIn the annex, there is an EXCEL macro to download. 
Answer
Since concrete has a nonlinear material behavior that can only be simulated with the CONCRETE NL module, it is not possible to analyze it by using the RF‑STABILITY addon module.
The use of another material model such as isotropic linear elastic or isotropic plastic would not represent the crack formation correctly, and the results are therefore not usable.
The stability analysis on columns can be performed with RF‑CONCRETE Columns or RF‑CONCRETE NL. You can find a small example under Downloads.
This example includes the design of a column by the RF‑CONCRETE Columns addon module. Make sure that the calculation of the internal forces in RFEM is performed according to the geometrically linear analysis and that no imperfections are required because the method used in the addon module takes them into account.
The example also includes the design with RF‑CONCRETE NL. Here, it is also necessary to calculate according to the secondorder analysis and it requires the imperfections in the form of inclinations. For better comparability, the layout of the longitudinal reinforcement was aligned with the result from RF‑CONCRETE Columns, as shown in Figure 01 and Figure 02. Since the reinforcement is optimized by the module after a new calculation, the desired reinforcement was saved as a template (see the red arrow).

Answer
The asynchronous calculation is used if a selfcreated program should only open or continue RFEM or RSTAB. When the calculation is complete, the event is transferred via a delegate. You can find a C# example in a Visual Studio project in the download area below. 
Answer
In fact, this error message appears only if a member end hinge that allows a rotation about the local xaxis has been assigned to a member at both ends. Thus, the member can rotate freely about its own axis and is therefore unstable.Assign a new release to one of the member ends where the degree of freedom φx is not hinged. 
Answer
In Table 1.3 Surfaces, you can specify the parameters in the corresponding tab for the automatic determination of the creep coefficient and shrinkage strain. It is also possible to enter userdefined values there, if necessary.
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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 standalone 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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