Assignment 6-Frontal Crash Simulation Challenge

FRONTAL CRASH:

it is one of the crash test, performed at the front portion of the car, to test the strength of a car and safety of the passengers.

1.Check unit system and either follow[Mg mm s] or [Kg mm ms].

to check for the units.

open the model in hypermesh

go to model-cards-begincards

in the left bottom we can see the units as mentioned in the below figure.

ans:

2.Create appropriate interface ,friction 0.2 and recommended parameters.

to create interface right click on the browsr select create inter type7

and select the appropriate methods as we did in the previous challenges.

and give friction value as 0.2.

3.Make sure of no penetrations and intersection.

t0 check penetrations go to tools penetration check.

in the left bottom box select entity type as components.

select the all componenents and click on check.

then in th left bottom, we can see the result as no collisions found as in the below figure.

5.Compare the model weight with the full scale 300k nodes model and use added masses to reach target weight 700kg while getting CG about the required range.

in hypermesh, select tools-mass-mass,cog,inertia

in that select cog the total mass is 188. and our target element is 700kg

for that create a mass, to create a mass , select solver creat new admass and select elemnts weight is 512kg.

select the nodes on back part of the given model.

and see for cogx,cogy,cogz. note the value of those points. and

select geometry - nodes- and paste the node values in x,y,z respectively.

and enter .

we'll see the new cog the model as reperesentd in yellow colour after adding the mass.

6.Time-step :0.5 to 0.1 microseconds.

go to solver select engine keywords _animdt and set the frequency to 5.

7.Use model checker to ensure good quality.

to go for model checker select tools-modelchecker-radios block

in the above figure, left boittom we can see no failed elements.

before going to simulation create the output blocks as to get the desired ouput results.

go to model click right side, create -out put blocks

then, in the bottom

select entity ID's and select the desired output required and name it.and include the created inputs as earlier..

output requests:

MASS AND ENERGY ERROR:

here, mass and erorrs are 0.5 and 0.264E-01 respectively which are under the control .

1.outputresults:

graph of IE,KE,CE,HE,TE

TOTALENERGY:total energy is defined as the sum of internal,potential,and kinetic energies and it is denoted by E.

here in the above graph it is indicated by light green colour which is above and is constant.throughout the time

KINETIC ENERGY: kinetic energy is the form of energy in an object tha posses due to its motion, in the above graph it is indicted by puple colour. initially its equal to the total energy but through the passing of time its gradually decreasing as crash happens.

HOURGLASSENERGY: It is the work done by the forces to counterattack the. hourglass modes. Hourglass modes are the non-physical, zero energy modes of distortion that yield zero strain and no stress.in the above graph, it is indicated by blue colour and its level is 0 throughout the crash

CONTACTENERGY:it is indicated black colour in the graph,its same as hourglass energy as th econtact energy is 0.

INTERNALENERGY:The internal energies of all the elements is summed to give the total internal energy.

1.Sectional force in the rails at location of indicated node 174247.

at the specific node the max sectional force at 8.3 at 44seconds.

the minimum force 0.8 at 72 seconds.

2.A pillar cross section

Apillar_leftside

A pillar_Right side

the max force at A pillar right side 0.108KN at 52secs

the minimumforce is occured at 0.004kn at 72secs.

• Acceleration curve received on the accelerometer at base of B pillar (on B pillar rocker).
• 
• accelorometer:Accelerometers measure acceleration, which in practical terms means changes in speed or direction. This can include bumps and vibrations, sharp increases or decreases in velocity such as hard vehicle acceleration or braking, forces that might indicate taking a turn too fast, or strong impacts.

intrusions on the dash wall 66695,66244.

intrusion results when the energy of the crash exceeds the strength of the vehicle frame, resulting in a violation of the occupant compartment.

• Shotgun cross sectional forces.

the maxforce at shotgun is 6.9KN at36seconds.

the minimum force is 1KN at 28seconds

• Axial force received on the rails from bumper.

the maxforce of 2.00KN at 20 seconds

the minimum force of 0.008 at 49 seconds

i got the following errors.

1.empty blocks

sol: i selected the error it displayed the error and i have selected the empty block and deleted.

2.number of variables

sol: in the outblocks initially number of variable is 0, later i changed to 1.

3.inivel :

the components need to selected all but instead i selected 1 component, later in the inivel i selected components and in that i selected all the components.