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  1. Rajeev

    crushing of honeycomb

    Dear George , Thanks for the reply. Some of the elements outside the contact area are showing more than 20mm deflection. It is happening when the projectile is coming out of the Back facsheet. I have attached the Image for your reference. I have asked for Normal force on the impactor during the process through TH card available in radioss. Time history plot shows the reduction of load when the front facheet breaks but it doesnot show any thing for back facheet rupture. Ideally when the impactor hits the back facheet the load should increase , The load increase will have till the point of rupture of second facheet after that the load should reduce. This phenomenon is not reflected in the simultation plz comment.
  2. Rajeev

    crushing of honeycomb

    Dear George, I have tried to simulate contact using RWALL option . I created a rigid sphere (RWALL) and imposed a constant velocity on the sphere. Slave nodes I have choosen the Sandwich panel in RWALL option. Top,bottom facesheet is connected with honeycomb through TYPE -2 Contact. During Checking process in RADIOSS I am getting warning message of INCOMPATIBLE KINEMATIC CONSTRAINT. While the job still runs but during simulation in each step ERR comes out to be -99.9%. Time history plot of RWALL is generated . In the simulation i can see the large irregular behavior of elements when sphere comes out of bottom facesheet. Can you pls let me know why this is happening. mode_law27_Wall_0000.rad
  3. Rajeev

    crushing of honeycomb

    Dear George, Thank you for the reply. I have used LAW27 as material model with failure strain of 0.15. I want to plot the time history plot of total load coming onto hemishpere. Experimental value is near to 120kg . I could see option of nodal and elemetal contact force but summing the all nodal contact forces i am not getting in hyperview. Can you tell me how to sum up the forces coming on to hemisphere during each load step. I have attached the file for your reference. mode_law27_2_0000.rad
  4. Good evening, I was going through the Tutorial 11  (Example -11 Tensile Test). In the Fig 30 Eps_max (strain) is chosen to be 47% similarly subsequently in LAW 27 Emax is chosen as 16 . Can you explain me why we have to choose so large value of True strain when actually material fractures at engineering strain of 0.1(approx) .

  5. Rajeev

    crushing of honeycomb

    Dear George I am trying to simulate crushing of Honeycomb sandwich panel. The speed of the indentor in 25mm/min. I have used Johnson Failure to account for material damage. In this simulation force displacement is asked. I am getting quite high value of Force also I am not see the cell wall buckling , I am attaching my file for the reference. If possible let me know what is missing in the generated model. Thanks UTM_25MM_HONEYCOMB_0001.rad UTM_25MM_HONEYCOMB_0000.rad
  6. Hi I am trying to simulate a impact condition . Simulation is running but steel sphere is not penetrating the sandwich panel . I am attaching the file here can any one suggest me how to proceed in this . I have used johnson cook plasticity model for aluminium . Cantilever_Impact_NAL_17_16_0000.rad