Week - 3 Drop test Challenge

G DRIVE URL: https://drive.google.com/drive/u/0/folders/1S18pT4BTUAOJ-_CcfmpdcvvKG5dY2Guq

Aim:

• To perform the basic drop test simulation from the given .k file and obtain the result evalute with the different materials like shell plate and sloid plate

Model setup:

• Before we gone set up the model which unit system are followed must we know to find that goto>FEM>Element tool>measure
• As in above image shows the the nit system is should be in a mm,ms,Kg,Pa only and the height between the ground to phone is 20.913mm

Base set up of Keywords

• Material creation
• section creation
• Part defination
• Boundary condition creation
• Contact defination
• Velocity assign
• Control defination
• Output request(data base)

MATERIAL CREATION:

• Before creation of the materials what are the parts list available to find that goto>model and part>part data. has seen the it contain the 3 parts 2 sloid and one shell
• First we consider the the phone is drop in the shell plate so, we not need the sloid plate and delete that and chane the name auto created from shell plate and phone
• From the eabove material property we take the rigig plate is stell and the phone is the alumium property
• to create the Phone material cards goto>keywors manger>all>024_piece_wise_liner_material. in that give title as phone material give id,apply the above values
• In the same way we create the another material card as name of 020_rigid and the title is shell_plate and apply the id as 2 and apply the above value

SECTION CREATION(goto>keywords manger>all>section)

• After craetion of the materials we define the section of materials.In this section, the element formulation, integration rule, nodal thicknesses, and cross sectional properties are defined.
• In that we have both shell part and sloid part we define the two section id in cards of shell and sloid
• In the shell part we give elform as a 2 which use mostly and the NIP(number of intergration point)is 2 which indicate after the dispalcement of nodel at the particular time step the value is integrated with the 2 point of the elements each elements
• In the slod part we give the eleform is 1 which indicate th econstant stress solid element (default)

PART DEFINATION(goto>keyword manger>part>)

• As we given the materials and section are respectively given

BOUNDARY CONDITION CREATION(goto>create entity>boundary>spc>create)

• As we understand this drop test so the rigid plate is fully constraines with 6 degree of freedom for that we create the SPC constraint

VELOCITY ASSIGN(goto>create entity>Intial>velocity)

• The phone is falling the -z direction with the velcoity of -5.94 mm/ms with iinclude of gravitnational force also

CONTACT DEFINATION(goto>key word manger>all>contact>automatic surf to surf contact)

• As we know the the phone is should be contact with the rigid plate during the drop so that we define the contact between both in there the master is define as a rigid plate and slave is phone

CONTROL DEFINATION

• *cotrol_accuracy=Define control parameters that can improve the accuracy of the calculation. where osu=1(objective stress updates) and inn=2(On for shell and thick shell elements (default for
  implicit))
• *control_energy=Provide controls for energy dissipation options. where HGEN=2(Hourglass energy calculation option),RWEN=2(energy dissipation is computed and included in the
  energy balance ),SITEN=2(energy dissipation is computed and included in the energy balance),RYLEN=2(energy dissipation is computed and included in the energy balance.)
• *control_hourglass=Redefine the default values of hourglass control type and coefficient. where ihq=1 and qh=0.1
• *control_termination=Stop the job. dt=5ms
• Thses are the control cards are applied

OUTPUT REQUEST OR DATA BASE CARDS

• ASSCII=>SLEOUT,RCFORC,NODOUT,MATSUM,GLSTAT,ELOUT
• BINIARY_D3=This keyword is used to request binary output,Database for entire model.
• Binary_d3thdt=Database containing time histories for subsets of elements and
  nodes.

POST PROCESSOR

• CASE-1(RIGILD SHELL PLATE)
• This image which shows the impact or contact with the rigid surface with the time step of 3.2 ms due to the contact between to part some opposing force are created in name of stress the stress value is 1.149e-1 kg/mm*ms2 after some time the it come the low value due to the the phone is bounce and no contacting between them and also the stress is evenly distrubuted around the parts
• On the other hand the final time step the stress of the part is 2.288e-2 is reduce due to the energy dissipation
• Internal energy is defined as the energy associated with the random, disordered motion of molecules. It is separated in scale from the macroscopic ordered energy associated with moving objects; it refers to the invisible microscopic energy on the atomic and molecular scale.As we seen the graph phone IE and KE time 0 the energy also 0 which indicate there no energy dissipation between phone and impacter but time 3.2 there is contact hapening between the phone and plate so, that the energy dissipation occur so,that internal energy of the phone is increased after some time the it come the low value due to the the phone is bounce and no contacting between them and also the stress is evenly distrubuted around the parts
• the kinetic energy (KE) of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes.in the same way but the energy dissipation happening for kinetic energy
• Hourglass (HG) modes are nonphysical, zero-energy modes of deformation that produce zero strain and no stress. Hourglass modes occur only in under-intetgrated (single integration point) solid, shell, and thick shell elements. the graph show the upto the time step 3.2 the HG is constant but after the nodal displacement occur the number of intergration point which given to the section part wil act and calculate the hourglass after the 32 ms seconds the hour glass futher incraese upto the 0.15 at the end of the time step

CASE-2(SLOID PLATE AS RIGID PART) note:same material property

• In case two replace the shell rigid plate to sloid plate and the material property are same but section only different in the last time step the the stres svalue are 4.8e-3 and the internal energy of the is is very small change but the kinitetic energy is reduced and constent at the time step of 3.2ms
• in this graph showing the hourglss is suddely increase because of the impacting time step 32ms the value is 2.3 andit gose the futher and make constant at the time step of 5 and the energy is 2.5.

RESULT AND LEARNING OUTCOMES

• Through the assignment we learn the basic and simple impact test in explicit method and geting the various type of graph
• through this assignment we learn the how apply the velocity, hourglass,control cards etc..
• through this assignment various type enegy dissipation curve are leared.