Drop test Challenge

AIM : To Create a Simulation file for DROP_TEST in LS_DYNA as a keyword file for the parts PHONE and a plate acts like GROUND.

OBJECTIVE :

• open (or) upload the given keyword data file in LS_PrePost.
• Assign keyword card as per the requirements with the data values in it.
• check for the keyword card errors in MODEL CHECK.
• Run the file in LS_DYNA pogram manager for Post results.
• plot the results and graphs.

PROCEDURE :

LS-PrePost :

• load the given keyword file in LS-prepost by using "open keyword file" option from file.
• now as per the requirement for drop test simulation we have two parts (1) phone and (2) plate acts like ground.
• for the part "plate" which is acting like a ground we have to provide the material card of "RIGID" Material, as the part is a rigid part.
• for the "mobile" part we are giving the "piecewise_linear_plasticity" card, so that the part contains elasticity.
• as for the "rigid" material card, we are providing the data of "STEEL" material as density = 7.8e-9 g/mm^3, young's modulus = 200000 Mpa, poison's ratio= 0.28 and as the part has to be rigid part so we constrain centre of mass in all DOF.
• for the "piecewise_linear_plasticity" card, we are providing data of "POLYCARBONATE" material as density = 1.2e-9 g/mm^3, young's modulus= 2600Mpa, poison's ratio= 0.32, yield stress= 64 Mpa, Tangent modulus= 130 Mpa.
• in the below images you can see the card with values.
  
  
  
  
• after that we have to create "SECTION" card for the parts, as the elements are formed as "HEXAHEDRAL mesh elements" we are taking "solid" section card.
• In the below images you can see the "Section" card with value's.
  
  
  
  
• now as we created the "material" and "section" card for parts, we have to go to "part" card to assign the following created cards as per requirement.
• In the below images you can see the (1) ground_plate is assigned with steel material id (1) and the phone is assigned with polycarbonate material id (2) and both the parts have same section card of "solid".
  
  
  
  
  
  
• now we have to set data of nodes for acting velocity and to define contact relation.
• for that we have to go to "set_data" > "set_node" and "set_data"> "set_segm", in which we select the nodes according to the required DOF.
  
  
  
  
  
  
  
• after creating the nodes data, now we have to assign velocity card to "phone" part.
• for that we have to go for "initial"> "velocity" card in which we are selecting the "nodeset id" of "phone" and acting the velocity of 15000mm/s in reverse z-direction axis.
• after that we have to provide the relation of contact between the two parts, so for that we have to go "contact" > "surface_to_surface".
• In which we are selecting "slave_segment_id" as "phone" and "master_segment_id" as "ground_plate".
  
  
  
  
  
  
• now we have to provide "control"> "termination" card which is very important, it decides the termination time of ending the cycle of process.
• In the below images you can see the termination "ENDTIM" given as 0.01 sec.
  
  
  
  
• now we have to provide the time span of output data write, for that we have to go "DATABASE" > "BINARY_D3PLOT" option.
• In which we are given input data write time spam of 5e-4 sec.
• For "Global statistics data" we are selecting "DATABASE" > "ASCII" > "GLSTAT" card, in which we are providing time span for write data for every 5e-4 sec.
  
  
  
  
• after creating all the required keyword cards, now we have to check for any errors (or) warnings present in the cards.
• for that we have to go to "model check" tool in that "keyword check" option to be selected, if there is any error present it will be highlighted with the card.
• if there is any error (or) warning occurs in the keyword check, then we have to correct it by going on that card again and if no errors are present then we can proceed with the further procedure.
  
  
  
  
  
• after the model check, we have to save the keyword file with extension of ".k" and run the file in "LS-DYNA" Pogram Manager.
• you can open the file in "notepad++" for editing the script file of the keyword file.
• after a succesfull run of the keyword file we have the following data regarding the time taken, steps taken, etc in command prompt of LS-DYNA pogram manager.
• In the below image you can see the following data of regarding pogram runs in LS-DYNA manager.
  

RESULT :

the given task of creating the keyword file for "drop_test" is created and it runs perfectly in LS-DYNA manager.

the keyword file is saved and the output data file are also shared through the link given below for further procedure.

https://1drv.ms/u/s!AnGsOah9scM2a-VHOr4C7boh0Ak?e=6iwla5

we open the output "database_d3plot" and "glstat" files in the LS-Prepost and check for the "von mises stress" and plot the values of "kinetic", "internal" and "total" energy.In below images you can see the values.

At point of contact

At End of cycle

Data Plotted