Overview
The following functions have been added to Engineer's Studio® Ver.10.
 Mφ element that takes into account the influence of change in axial force
 Mθ model (spring element) that takes into account the influence of change in axial force
Both functions can be applied to uniaxial bending but not to biaxial bending. Use the fiber element for the biaxial bending
Mφ element that takes into account the influence of change in axial force
As for Mφ characteristics automatically created from sections, input the maximum and minimum value and the number of changing axial force in the Mφ Tables or Mφ Thumbnails in "Model Properties  Mφ Element Properties". Then press "Preprocess" button to calculate the same number of Mφ characteristics as the input number of axial force (Fig.1).
To calculate arbitrary Mφ feature that is not calculated from section automatically, input M and φ the same number as axial force directly.

Fig.1 Mφ feature that takes into account the influence of change in axial force 
When the FEM analysis is performed, Mφ features of each axial force are taken into account at the same time. The figure 2 is an example of an analysis of the case of 3 axial forces. Mφ characteristics when the axial force is N1, N2, and N3 are available.

Fig.2 Moment Curvature Mxφz Example of several Mφ characteristics according to 3 types of axial forces 
When a load is applied, in a step, all the three Mφ characteristics are updated at the same time as shown in Fig. 3 and reach the point A, B, and C. For example, when a new axial force acquired at that step is between N1 and N2, the linear interpolation is applied between A and B and creates a new bending moment and rigidity.

Fig.3 Moment Curvature Mxφz Response of several Mφ characteristics when monotonically increasing 
The unloading is handled in the same way. In a step, all the three Mφ characteristics are updated coinsidently as shown in Fig. 4 and reach the point D, E, and F. For instance, when a new axial force acquired at that step is between N1 and N2, the linear interpolation is applied between D and E and creates a new bending moment and rigidity.

Fig.4 Moment Curvature Mxφz Response of several Mφ characteristics when unloading 
Mθ Model (Spring Element) That Takes Into Account the Influence of Change in Axial Force
Handled in the same way as Mφ element above that is taking into account changes in the axial force.
Others
Response value and verification value that take into account changes in the axial force is also calculated for the curvature verification, plasticity rate verification (2012 specifications), residual displacement verification, and displacement verification (2017 specifications).
