| (1) | ### Start Time Loop #### |
| (2) | while dem_analysis.time < dem_analysis.end_time: |
| (3) | # update time parameters |
| (4) | dem_analysis.AdvanceInTime() |
| (5) | structural_analysis.AdvanceInTime() |
| (6) | # save the current position, forces, velocity, etc., of the DEM wall condition and particles |
| (7) | dem_analysis.SaveCurrentData() |
| (8) | # initialize time step |
| (9) | structural_analysis.InitializeSolutionStep() |
| (10) | # initial interface residuals |
| (11) | InitializeResiduals() |
| (12) | while interface_residual > interface_tolerance: |
| (13) | ### Solve DEM Problem #### |
| (14) | # reset the previous saved data of the particle to keep it at the same reference position in each inner loop step |
| (15) | dem_analysis.SetOldDataParticles() |
| (16) | # search and find neighbouring elements/particles which are in contact |
| (17) | dem_analysis.SearchOperations() |
| (18) | # calculate contact forces |
| (19) | dem_analysis.ForceOperations() |
| (20) | # integrate in time to obtain new position and velocity of DEM particles |
| (21) | dem_analysis.IntegrationOfMotion() |
| (22) | ### Map Contact Forces #### |
| (23) | # DEM to Structure |
| (24) | mapper.Map(DEMApplication.CONTACT_FORCES, StructuralMechanicsApplication.POINT_LOAD) |
| (25) | ### Solve Structural Mechanics Problem #### |
| (26) | # prediction step for solution scheme (if necessary) |
| (27) | structural_analysis.Predict() |
| (28) | # solve the FEM system of equations or explicitly integrate in time |
| (29) | structural_analysis.SolveSolutionStep() |
| (30) | ### Map Velocity and Displacement #### |
| (31) | # Structure to DEM |
| (32) | mapper.InverseMap(VELOCITY) |
| (33) | mapper.InverseMap(DISPLACEMENT) |
| (34) | ### Calculate Interface Residuals #### |
| (35) | calculate_displacement_residual() |
| (36) | calculate_velocity_residual() |
| (37) | # use the maximum residual for the convergence check |
| (38) | interface_residual = max(displacement_residual, velocity_residual) |
| (39) | ### Relax Exchange Data #### |
| (40) | dem_analysis.RelaxDisplacementAndVelocity() |
| (41) | dem_analysis.SetRelaxedDisplacementAndVelocity() |
| (42) | ### Update DEM #### |
| (43) | # update position of DEM wall |
| (44) | dem_analysis.MoveMesh() |
| (45) | # use the current position of the DEM wall condition and the last converged position to calculate the difference in displacement, which is used to calculate contact force |
| (46) | dem_analysis.CalculateDeltaDispFromIntermediatePos() |
| (47) | # finalize time step by updating state variables and spatial position |
| (48) | structural_analysis.FinalizeSolutionStep() |
| (49) | dem_analysis.FinalizeSingleTimeStep() |
| (50) | ### Finalize Applications #### |
| (51) | dem_analysis.Finalize() |
| (52) | structural_analysis.Finalize() |
