Initial Element Forces

 

 

 

Enter the internal member forces in the structure due to external loads for linear analysis. The member forces are calculated using Initial Force Control Data.

Initial member forces are generated from member forces due to a specific load combination, as controlled from Load > Initial Force > Small Displacement > Initial Force Control Data.  After Initial Force Control Data has been completed and analysis has been performed, the initial (internal) forces calculated can be checked in Results > Result Tables > Initial Element Force table.

Initial Element Forces are used to calculate geometric stiffness in general linear analysis.  This function includes geometric stiffness in linear stiffness.  It is applied to linear static, linear buckling, eigenvalue, response spectrum and time history analyses.

After copying the internal forces from the Results > Result Tables > Initial Element Force table and pasting them onto Load > Initial Force > Small Displacement > Initial Element Forces here, eigenvalue analysis can be performed in the completed model reflecting the geometric stiffness.  For Time History Analysis, if (Subsequent to) Initial Element Forces (Table) is selected in Add/Modify Time History Load Cases, time history analysis is performed using the Initial Element Forces of this table.

 

 

 

From the Main Menu select Load >  Static Load >  Initial Forces > Small > Initial Element Forces.

 

 

 

Axial-i: Axial force at i-end

Shear(y)-i: Shear force in the ECS y-dir at i-end

Shear(z)-i: Shear force in the ECS z-dir at i-end

Torsion-i: Torsional moment at i-end

Moment(y)-i: Moment about ECS y-dir at i-end

Moment(z)-i: Moment about ECS z-dir at i-end

Axial-j: Axial force at j-end

Shear(y)-j: Shear force in the ECS y-dir at j-end

Shear(z)-j: Shear force in the ECS z-dir at j-end

Torsion-j: Torsional moment at j-end

Moment(y)-j: Moment about ECS y-dir at j-end