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Answer
The shear correction factor is taken into account in the RFLAMINATE program 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 the shear stiffness itself can be found on page 15 of the English version to the manual of RFLAMINATE as follows:For the 10 cm thick plate in Figure 1, the calculation of the shear correction factor is shown. The equations used here are only valid for the simplified symmetrical plate structures!Layer z_min z_max E_x (z) (N/mm²) G_xz (z) (N/mm²) 1 50 30 11000 690 2 30 10 300 50 3 10 10 11000 690 4 10 30 300 50 5 30 50 11000 690 $\sum_iG_{xz,i}A_i=3\times0,02\times690+2\times0,02\times50=43,4N$$EI_{,net}=\sum_{i=1}^nE_{i;x}\frac{\mbox{$z$}_{i,max}^3\mbox{$z$}_{i,min}^3}3$$=11000\left(\frac{30^3}3+\frac{50^3}3\right)+300\left(\frac{10^3}3+\frac{30^3}3\right)$$+11000\left(\frac{10^3}3+\frac{10^3}3\right)+300\left(\frac{30^3}3\frac{10^3}3\right)+11000\left(\frac{50^3}3\frac{30^3}3\right)$$=731,2\times10^6Nmm$$\int_{h/2}^{h/2}\frac{\left(\int_z^{h/2}E_x(z)zd\overline z\right)^2}{G_{xz}(z)}\operatorname dz=\sum_{i=1}^n\frac1{G_{i;xz}}\left(χ_i^2(z_{i;max}z_{i,min})\;χ_iE_{i,x}\frac{z_{i,max}^3z_{i,min}^3}3+E_{i,x}^2\frac{z_{i,max}^5z_{i,min}^5}{20}\right)$$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}}=7964,7N/mm$This corresponds to the value output in RFLAMINATE (Figure 2). 
Answer
In RFGLAS, there are two different types of calculations. On the one hand, the socalled '2D' calculation. In this case, the glass structure is represented as a surface element. When considering the shear bond, an equivalent crosssection is determined using the laminate theory In contrast to this, there is the '3D' calculation. In this case, the layer structure is represented as a solid element in the calculation and thus the effectiveness of the stiffnesses between foil and glass is exactly determined when the shear bond is taken into account.
The RFGLAS manual, Chapter 2, also provides further information on method of analysis.

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 with the RFSTABILITY 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.
A stability analysis on columns can be performed with RFCONCRETE Columns or RFCONCRETE NL. You can find a small example in Downloads.
This example includes the design of a column by the RFCONCRETE Columns addon module. Make sure that the calculation of the internal forces in RFEM is performed according to the firstorder analysis and that no imperfections are required because the method used in the module takes them into account.
The example also includes the design with RFCONCRETE NL. Here again, it is necessary to calculate according to the secondorder analysis and imperfections in the form of inclinations are required. For better comparability, the layout of the longitudinal reinforcement was aligned with the result from RFCONCRETE Columns, as shown in Figures 01 and 02. Since the reinforcement is optimized by the module after a new calculation, the wanted reinforcement was saved as a template (see red arrow).

Answer
The choice of the solver method leading quickly to results depends on the complexity of the model and the main memory (RAM) that is available:
 For small and medium sized systems, the direct method is more effective.
 For very large structures, the iterative method leads to results more quickly.

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. 
Answer
RSTAB is a FEM program that uses trigonometric trial functions for the members. For this reason, members do not have to be subdivided for sufficiently accurate results and the calculation speed is correspondingly higher.
RSBUCK determines the eigenvalues of the stiffness matrix and can thus linearly calculate the critical load and buckling mode of the structure.
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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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