5. Example: movement of a pendulum with a large amplitude

# TITRE Simple pendulum in big swing

#

# PENDULE CONSTITUE FROM A ELEMENT OF CABLE (test SDNL100A).

#

RESU = DYNA_NON_LINE (MODELE =MO, CHAM_MATER = CHMAT, CARA_ELEM = CARA,

EXCIT =( _F (CHARGE = CHA1),

_F (CHARGE = CHA2)),

INCREMENT =_F (INST_INIT = 0., LIST_INST = L_ INST1),

ARCHIVAGE =_F (LIST_INST = L_ INST2),

SCHEMA_TEMPS =_F (SCHEMA =' NEWMARK ',

FORMULATION =' DEPLACEMENT '),

COMPORTEMENT =_F (RELATION = 'CABLE',

DEFORMATION = 'GREEN'),

CONVERGENCE =_F (RESI_GLOB_RELA = 1.E-6,

ITER_GLOB_MAXI = 100),

NEWTON =_F (REAC_ITER = 1)

)

FIN ()

• the load cha1 requires node 1 to remain fixed and node 2 to move in the vertical plane XZ,

• the load cha2 is gravity,

• command DYNA_NON_LINE specifies that:

• the method of integrating time will be that of “NEWMARK”, « trapezium rule » (also called mean acceleration), because there are no arguments under “NEWMARK”,

• the initial state, at time 0, has zero displacement, that is to say that the movements will be evaluated from the initial position, and at zero speed,

• the iterative calculation will continue as long as the relative residue is \(>{10}^{\mathrm{-}2}\), but the number of iterations will be limited to 100,

• finally the tangent matrix of the linear system to be solved will be reevaluated at each iteration (by default since the NEWTON keyword is absent).