*HEADING DYNAMIC LOADING OF AN ELASTOMERIC, VISCOELASTIC FOAM BLOCK ************************************************** ** Step 1: Apply a gravity load on the point mass of the punch in a visco step and let the foam relax fully. ** Step 2: Apply a sinusoidal half-wave force on the punch and measure the displacement, velocity and acceleration response in a dynamic step. ** Step 3: After removing the force, continue measuring the dynamic response. ** (Units: N, mm, sec) ************************************************** *PREPRINT,MODEL=YES,HISTORY=NO *RESTART,WRITE *NODE 1, 0., 300. 19, 0., 0. 481, 300., 300. 499, 300., 0. 601, 600., 300. 619, 600., 0. *NSET,NSET=N1 1, *NSET,NSET=N19 19, *NSET,NSET=N481 481, *NSET,NSET=N499 499, *NFILL,NSET=TOP,BIAS=.85 N1,N481,12,40 *NGEN,NSET=TOP 481,601,40 *NFILL,NSET=BOT,BIAS=.85 N19,N499,12,40 *NGEN,NSET=BOT 499,619,40 *NFILL,NSET=ALLN,BIAS=.9 TOP,BOT,9,2 *NSET,NSET=CENTER,GENERATE 1,19 *ELEMENT,TYPE=CAX4 1,3,43,41,1 *ELGEN,ELSET=FOAM 1,15,40,10,9,2,1 *ELSET,ELSET=CENT,GENERATE 1,141,10 61,69 *ELSET,ELSET=ETOP,GENERATE 1,101,10 *ELSET,ELSET=UPPER,GEN 1,141,10 *NODE,NSET=PUNCH 1000,0.,500. *ELEMENT,TYPE=MASS,ELSET=PMASS 1001,1000 *MASS,ELSET=PMASS 0.2, *SOLID SECTION,ELSET=FOAM,MATERIAL=FOAM, ORIENTATION=RECT *ORIENTATION,NAME=RECT,SYSTEM=RECTANGULAR 1.,0.,0., 0.,1.,0. 3,0. ****************************************** *MATERIAL,NAME=FOAM *HYPERFOAM,N=2,TEST DATA INPUT,POISSON=0.0, MODULI=INSTANTANEOUS *UNIAXIAL TEST DATA -.0217, -.05 -.0317, -.10 -.0367, -.15 -.0402, -.20 -.0433, -.25 -.0467, -.30 -.0504, -.35 -.0542, -.40 -.0604, -.45 -.0668, -.50 -.0759, -.55 -.0909, -.60 -.1083, -.65 -.1410, -.70 -.1933, -.75 -.2896, -.80 *SIMPLE SHEAR TEST DATA .0140, .08, .0046 .0334, .16, .0166 .0533, .24, .0366 .0853, .32, .0573 .1280, .40, .0817 .1653, .48, .1098 .2080, .56, .1394 .2560, .64, .1666 .2987, .72, .1904 *VISCOELASTIC,TIME=RELAXATION TEST DATA *SHEAR TEST DATA,SHRINF=0.5000 1.0000, 0.0001 0.9695, 0.001 0.9417, 0.002 0.8722, 0.005 0.7913, 0.010 0.7043, 0.020 0.6233, 0.050 0.5736, 0.100 0.5271, 0.200 0.5013, 0.500 0.5000, 1.000 *DENSITY 1.E-11, ********************************************* *BOUNDARY BOT,1,2 CENTER,1 1000,1 1000,6 ********************************************* *SURFACE,TYPE=SEGMENTS,NAME=IMPACTOR START,141.42,641.42 CIRCL,-1.,300.,0.,500. *SURFACE,TYPE=ELEMENT,NAME=TARGET ETOP,S3 *RIGID BODY,REF NODE=1000, ANALYTICAL SURFACE=IMPACTOR *CONTACT PAIR,INTERACTION=ROUGH TARGET,IMPACTOR *SURFACE INTERACTION,NAME=ROUGH *FRICTION 0.8, ********************************************* *AMPLITUDE,NAME=RAMP,VALUE=RELATIVE ** Ramp to full load in 2 sec 0.,0., 2.,1., 10.,1. *AMPLITUDE,NAME=SINE,DEFINITION=PERIODIC, VALUE=ABSOLUTE ** Force amplitude=5000 N of a half-sine wave ** for a 1 sec period 1,3.1416,0.,0. 0.,-5000. ********************************************* *STEP,NLGEOM,INC=100,UNSYMM=YES Apply gravity force. *VISCO,CETOL=0.01 .01,5. *DLOAD,AMPLITUDE=RAMP PMASS,GRAV,9810.,0.,-1.,0. *OUTPUT,FIELD,FREQUENCY=10 *CONTACT OUTPUT,SLAVE=TARGET,MASTER=IMPACTOR, VARIABLE=PRESELECT *NODE OUTPUT U,V,A,RF *ELEMENT OUTPUT,ELSET=FOAM S,LE *OUTPUT,HISTORY,FREQUENCY=1 *NODE OUTPUT,NSET=PUNCH U,V,A,RF *ELEMENT OUTPUT,ELSET=CENT MISES,LE22,S22 *PRINT,CONTACT=YES *ENERGY PRINT,FREQUENCY=5 *ENERGY PRINT,ELSET=FOAM,FREQ=5 *ENERGY PRINT,ELSET=CENT,FREQ=5 *CONTACT PRINT,SLAVE=TARGET **CONTACT FILE,SLAVE=TARGET,FREQUENCY=10 *EL PRINT,FREQUENCY=20,ELSET=CENT S, SINV, LE, EE, CE, LOADS, *NODE PRINT,FREQUENCY=20 U, CF,RF *END STEP ******************************************** *STEP,NLGEOM,INC=200,UNSYMM=YES Apply dynamic load. *DYNAMIC,HAFTOL=5000. .01,1. *DLOAD PMASS,GRAV,9810.,0.,-1.,0. *CLOAD,AMPLITUDE=SINE 1000,2 *END STEP ******************************************** *STEP,NLGEOM,INC=300,UNSYMM=YES Remove load. *DYNAMIC,HAFTOL=5000.,INITIAL=NO .01,10. *DLOAD PMASS,GRAV,9810.,0.,-1.,0. *CLOAD,OP=NEW *END STEP