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9. 1次元弾性接触

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plan_elastic_contact_1d

入力ファイル

elastic_contact_1d.mbd
# elastic_contact_1d.mbd

#-----------------------------------------------------------------------------
# [Data Block]

begin: data;
   problem: initial value;
end: data;

#-----------------------------------------------------------------------------
# [<Problem> Block]

begin: initial value;
   initial time:   0.;
   final time:     4.;
   time step:      1.e-3;
   max iterations: 10;
   tolerance:      1.e-7;
end: initial value;

#-----------------------------------------------------------------------------
# [Control Data Block]

begin: control data;
   use: rigid bodies, gravity, in assembly;
   output frequency: 10;
   structural nodes: 3;
   rigid bodies:     1;
   joints:           5;
   forces:           1;
   gravity;
end: control data;

#-----------------------------------------------------------------------------
# Design Variables
set: real M  = 1.;     # Mass
set: real L  = 1.;     # Spring Natural Length
set: real K  = 40.;    # Spring Stiffness
set: real H  = -1.5;   # Table Position
set: real Kc = 10000.; # Contact Stiffness
set: real Ec = 1.2;    # Contact Stiffness Exponent
set: real Cc = 10.;    # Contact Damping
set: real Dc = 0.0001; # Contact Damping Activation Depth

#-----------------------------------------------------------------------------
# Node Labels
set: integer Node_Actuator = 1;
set: integer Node_Mass     = 2;
set: integer Node_Ground   = 3;

# Body Labels
set: integer Body_Mass = 1;

# Joint Labels
set: integer JoDrivp_Actuator      = 1;
set: integer JoInlin_Actuator_Mass = 2;
set: integer JoPrism_Actuator_Mass = 3;
set: integer JoDfmd_Spring         = 4;
set: integer JoClamp_Ground        = 5;

# Force Labels
set: integer FoStr_Contact_Mass = 1;

#-----------------------------------------------------------------------------
# Scalar Functions 
scalar function: "cubstep",
   cubicspline, do not extrapolate,
      -0.03, 0.00,
      -0.02, 0.00,
      -0.01, 0.00,
       0.00, 0.00,
       1.00, 1.00,
       1.01, 1.00,
       1.02, 1.00,
       1.03, 1.00;

#-----------------------------------------------------------------------------
# [Nodes Block]

begin: nodes;

   #-----------------------------------------------------------------------------
   # Nodes
   structural: Node_Actuator, dynamic,
      null, # absolute position
      eye,  # absolute orientation
      null, # absolute velocity
      null; # absolute angular velocity
      
   structural: Node_Mass, dynamic,
      0., 0., -L, # absolute position
      eye,        # absolute orientation
      null,       # absolute velocity
      null;       # absolute angular velocity
      
   structural: Node_Ground, static,
      null, # absolute position
      eye,  # absolute orientation
      null, # absolute velocity
      null; # absolute angular velocity
      
end: nodes;

#-----------------------------------------------------------------------------
# Plugin Variables
set: [node, DZ, Node_Mass, structural, string="X[3]"];
set: [node, VZ, Node_Mass, structural, string="XP[3]"];

#-----------------------------------------------------------------------------
# [Elements Block]

begin: elements;

   #-----------------------------------------------------------------------------
   # Bodies
   body: Body_Mass, Node_Mass,
      M,    # mass
      null, # relative center of mass
      eye;  # inertia matrix

   #-----------------------------------------------------------------------------
   # Joints
   joint: JoDrivp_Actuator,
      drive displacement pin,
         Node_Actuator, 
            null,                                           # node offset
            null,                                           # offset
         single, 0., 0., 1., sine, 1., pi/2., -1., one, 0.; # position
      
   joint: JoInlin_Actuator_Mass, 
      in line,
         Node_Actuator,
            null, # relative line position
            eye,  # relative normal direction
         Node_Mass;
      
   joint: JoPrism_Actuator_Mass,
      prismatic,
         Node_Actuator,
         Node_Mass;
         
   joint: JoDfmd_Spring,
      deformable displacement joint,
         Node_Actuator,
            null,
         Node_Mass,
            null,
         linear elastic isotropic, K,
         prestrain, single, 0., 0., -1, const, L;
         
   joint: JoClamp_Ground,
      clamp,
         Node_Ground,
            null, # absolute position
            eye;  # absolute orientation
   
   #-----------------------------------------------------------------------------
   # Forces       
   force: FoStr_Contact_Mass,
      absolute,
         Node_Mass,                                                
            position, null,                                       # relative arm
         single, 0., 0., 1.,
            string, "max(0,Kc*sign(H-DZ)*abs(H-DZ)^Ec
                          -Cc*VZ*model::sf::cubstep((H-DZ)/Dc))"; # force value
   
   #-----------------------------------------------------------------------------
   # Gravity                        
   gravity: 0., 0., -1., const, 9.81;
   
end: elements;