Caesar ii program solves a set of equations which is written in matrix form as :

P= KD

where P= Load vector, K= stiffness matrix , D= displacement.

1.I want to know what are the factors/parameters that are affecting K(stiffness matrix) with detail equations.
2.How caesar ii programmer consider the above equation for different scenarios like weight,pressure,thermal expansion,psv forces,seismic,wind effect etc.

Kindly give your expert advise.

1) Refer to any text book on matrix analysis and 3d beam elements.

2) These are just different load components, in the {P} vector.