solveBoundaryConditions

Description

SAENO finds a set of nodal displacements, such that the resulting nodal forces counterbalance the external nodal forces stated as boundary condition. While doing it does not modify the displacement of the fixed nodes. The program minimizes the mismatch between external and nodal force (the residuum) using the Newton–Raphson method. SAENO computes the first derivative of the nodal forces by the nodal displacements (the stiffness matrix). The condition that the internal forces counterbalance the nodal forces can then be expressed a set of linear equations, which is solved using conjugate gradient method. The result of this computation is a suggested displacement step for every node. The suggested displacement step is then multiplied by REL_SOLVER_STEP and added to the current displacement for every node. The program iterates this procedure until the relative standard deviation of the force mismatch (of the residuum) over the last 5 iterations drops below REL_CONV_CRIT or a total of REL_ITERATIONS is reached.

Table of Parameters

name	type	default	explanation
REL_ITERATIONS	integer	300	Maximal number of iterations.
REL_CONV_CRIT	float	0.01	The program will stop iterating if the relative standard deviation of the residuum of the last 5 iterations drops below this parameter.
REL_SOLVER_STEP	float	0.066	At the end of every iteration the program updates the configuration by the computed displacement step multiplied by this parameter.
DATAOUT	string	empty	Directory in which the relrec file is saved. This parmater is shared between x, x, x and x.
REL_RELREC	string	relrec.dat	The norm of the displacement step of that iteration, the total strain energy and the residuum over the iterations are recorded (in this order) into the file specified by this parameter in the DATAOUT directory.

Console Output

F.A.Q.