Methods for solving nonlinear equations
The application of the FE method for solving nonlinear differential equations results in algebraic equations that can be expressed in the following form:
where
|
K |
stiffness matrix of the model |
|
d |
vector of the unknown (usually of nodal parameters of the deformation) |
|
f |
vector of the right sides (usually of nodal forces) |
The matrix K is the function of d and therefore cannot be evaluated without knowing the vector of the system roots d. Since this nonlinear system cannot be solved directly, iteration methods that are aimed at progressively increasing the precision of the solution are used.
RF-CONCRETE NL uses the iteration method according to Picard. This method is also known as the Direct Iteration Method or Secant Modulus Method.
