# elastic_contact_1d.mbd #----------------------------------------------------------------------------- # [Data Block] begin: data; problem: initial value; end: data; #----------------------------------------------------------------------------- # [ 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;