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Answer
The difference between both material models is as follows:
In the Isotropic Nonlinear Elastic 1D material model, no plastic deformations are considered. This means that the material returns to its initial state after the load relief.
In the case of the Isotropic Plastic 1D material model, the plastic deformation is considered.
For both material models, the nonlinear properties are defined in an additional dialog box. When entering data by means of a diagram, it is possible in both models to define the distribution after the last step.
The Isotropic Nonlinear Elastic 1D material model allows for the antisymmetric input of the stressstrain diagram (different for the positive and negative zone), whereas the isotropic Plastic 1D model only allows for symmetric input.

Answer
When using a diagram in the program, the first strain is always given (initial strain). It depends on the resulting modulus of elasticity and cannot be controlled directly. For this, you can use a trick in the program and adjust the first strain to a desired value anyway. To do this, you have to calculate the initial modulus of elasticity and enter it in the material parameter. In your case, it would be possible to use the following procedure.

Answer
The "RF‑MAT NL" addon module allows you to use the nonlinear material model "Isotropic Damage 2D/3D" in RFEM to define the stressstrain diagram for the steel fiberreinforced concrete. The internal forces and deformation can be determined in the subsequent nonlinear FE calculation. 
Answer
The RF/DYNAM Pro  Equivalent Loads addon module only contains a linear analysis of structures. If you now apply a nonlinear model for the calculation, RF‑/DYNAM Pro  Equivalent Loads will modify it internally and treat it as a linear model. The nonlinearity in your model is the masonry, which cannot absorb any tensile forces.
The problem is as follows: RF/DYNAM Pro  Equivalent Loads calculates the equivalent loads linearly and exports the load cases from them. However, the load cases are subsequently calculated nonlinearly on the basis of the material model, which is not entirely correct. Furthermore, the results are superimposed according to the SRSS or CQC method, which results in tensile and compressive forces being present in the model.
In this case, you could change the masonry to isotropic linear and work with linear properties of the material model, for example. Additionally, it is possible to insert line hinges at this location, which could be used to avoid the moment restraint, for example.

Answer
The material model according to TsaiWu unifies the plastic with the orthotropic properties. In this way, it is possible to specifically model the materials with anisotropic properties, such as plastics or timber. If the material is plastified, the stresses remain constant. The redistribution is carried out according to the stiffnesses available in the individual directions. The elastic area corresponds to the Orthotropic Elastic  3D material model. For the plastic area, the yielding according to TsaiWu applies:${\text{f}}_{\mathrm{crit}}\left(\mathrm\delta\right)=\frac1{\mathrm C}\left[\frac{\left({\mathrm\delta}_{\mathrm x}{\mathrm\delta}_{\mathrm x,0}\right)^2}{{\mathrm f}_{\mathrm t,\mathrm x}{\mathrm f}_{\mathrm c,\mathrm x}}+\frac{\left({\mathrm\delta}_{\mathrm y}{\mathrm\delta}_{\mathrm y,0}\right)^2}{{\mathrm f}_{\mathrm t,\mathrm y}{\mathrm f}_{\mathrm c,\mathrm y}}+\frac{\left({\mathrm\delta}_{\mathrm z}{\mathrm\delta}_{\mathrm z,0}\right)^2}{{\mathrm f}_{\mathrm t,\mathrm z}{\mathrm f}_{\mathrm c,\mathrm z}}+\frac{{\mathrm\tau}_{\mathrm{yz}}^2}{{\mathrm f}_{\mathrm v,\mathrm{yz}}^2}+\frac{{\mathrm\tau}_{\mathrm{xz}}^2}{{\mathrm f}_{\mathrm v,\mathrm{xz}}^2}+\frac{{\mathrm\tau}_{\mathrm{xy}}^2}{{\mathrm f}_{\mathrm v,\mathrm{xy}}^2}\right]$where:${\mathrm\delta}_{\mathrm x,0}=\frac{{\mathrm f}_{\mathrm t,\mathrm x}{\mathrm f}_{\mathrm c,\mathrm x}}2$${\mathrm\delta}_{\mathrm y,0}=\frac{{\mathrm f}_{\mathrm t,\mathrm y}{\mathrm f}_{\mathrm c,\mathrm y}}2$${\mathrm\delta}_{\mathrm z,0}=\frac{{\mathrm f}_{\mathrm t,\mathrm z}{\mathrm f}_{\mathrm c,\mathrm z}}2$$\mathrm C=1+\left[\frac1{{\mathrm f}_{\mathrm t,\mathrm x}}+\frac1{{\mathrm f}_{\mathrm c,\mathrm x}}\right]^2\frac{{\mathrm E}_{\mathrm x}{\mathrm E}_{\mathrm p,\mathrm x}}{{\mathrm E}_{\mathrm x}{\mathrm E}_{\mathrm p,\mathrm x}}\mathrm\alpha+\frac{{\mathrm\delta}_{\mathrm x,0}^2}{{\mathrm f}_{\mathrm t,\mathrm x}{\mathrm f}_{\mathrm c,\mathrm x}}+\frac{{\mathrm\delta}_{\mathrm y,0}^2}{{\mathrm f}_{\mathrm t,\mathrm y}{\mathrm f}_{\mathrm c,\mathrm y}}+\frac{{\mathrm\delta}_{\mathrm z,0}^2}{{\mathrm f}_{\mathrm t,\mathrm z}{\mathrm f}_{\mathrm c,\mathrm y}}$You can imagine the yield criterion as an elliptical surface in a sixdimensional stress space.If one of the three stress components is applied as a constant value, the surface can be projected onto a threedimensional stress space. The projection of yield surfaces for normal stresses according to Tsai‑Wu: if the value for fy (σ) is smaller than 1, the stresses rest within the elastic area. The plastic area is reached as soon as fy (σ) = 1; the values greater than 1 are not allowed. The model behavior is idealplastic, which means there is no stiffening. 
Answer
As soon as the material with a nonlinear material model assigned has been created, the license for RF‑MAT NL is used. The license is not released until you close the file or change the material model. Therefore, the license is used for the entire duration, even if no calculation is carried out. 
Answer
This is possible with the RF‑LOAD‑HISTORY add‑on module.
It is important to use the "Plastic 2D/3D" or "Plastic 1D" material model. How it works in practice is shown in this recording of a Dlubal Info Day.

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Young's modulus is calculated for each step of the defined diagram according to Hooke's law:
ε = σ / EThe value of the current step is displayed beneath the diagram on the right side (see Figure 01).

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The addon module RFMAT NL is already integrated in RFEM 5. It is assumed that the following material models can be used:Isotropic Plastic 1DIsotropic Plastic 2D/3DIsotropic Nonlinear Elastic 1DIsotropic Nonlinear Elastic 2D/3DOrthotropic Plastic 2DOrthotropic 3D PlasticIsotropic Masonry 2DIsotropic Damage 2D/3D 
Answer
No, it is not absolutely necessary to calculate according to the secondorder or large deformation analysis when using a nonlinear material model. The material nonlinearity is also considered in the case of the calculation according to the linear static analysis.
The calculation according to the secondorder analysis or the large deformation analysis means that the equilibrium is set on a deformed structure. So it is geometric nonlinearity.
The difference between the secondorder and large deformation is that large rotation may occur in the case of the large deformation analysis.
Thus, if there is no stability problem or if the stability problem is further analysed, the calculation according to the linear static analysis is sufficient.
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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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