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[3343534645]

I derived Cook's theory and also rewrote Borst's theory. When they introduced the calculation formula for the geometric stiffness matrix of solid elements, the geometric stiffness matrix they computed had non-zero elements. Why is the geometric stiffness matrix output by ANSYS APDL entirely composed of non-zero elements? Was the calculation incorrect?

[3343534645]

I derived Cook's theory and also rewrote Borst's theory. When they introduced the calculation formula for the geometric stiffness matrix of solid elements, the matrix had zero elements. Why is the geometric stiffness matrix output by ANSYS APDL entirely composed of non-zero elements? Was the calculation incorrect?

[Harshvardhan]

Hi,
It seems that you have posted another thread with same question. Since this is a duplicate thread, I will be closing this discussion. Other discussion can be found in this link:
Is ANSYS APDL’s geometric stiffness matrix for solid elements wrong?

Regards,
Harshvardhan