Week - 3 Drop test Challenge

The given problem of mobile drop test main factors to consider before the simulation are boundary conditions.

As the goal of this task is to set up the correct setup quantitatively and so many factors like the angle of impact, the material of mobile, model of mobile are simplified.

Now in considering the current problem, the mobile drop test, the first thing is to calculate the instantaneous velocity of mobile before impact. To calculate the velocity I have considered the mobile is fell from a hand of the user from the height of approx 1500 mm height. Now using free-fall equation to calculate the velocity of mobile.

v = sqrt(2gd)

where,

d = height

v = final velocity

g = acceleration due to Gravity

after calculations, the speed is 5.425 mm/ms. In addition to the Initial velocity of mobile.

Now, as the material properties are simplified, elastic steel material is assigned to mobile. Further at the time of impact, the mobile comes in contact with the ground, as the forces/ stress-induced in the ground at the time of impact are not important, the ground is considered rigid.

(Note: To shorten the simulation time, the mobile is transformed by -15 mm in the z-direction to have it closer to the ground.)

Now after considering initial boundary conditions, the simulation is set up for given mesh file and the results of simulations are discussed below:

Before impact, the KE of the system was constant due to initial velocity and also in the contour plot through we see the some colors the values are almost equal to zero.

At the time of impact the maximum stresses are induced at point of contact and due to absence of gravity and weight of mobile the mobile rebounds in the air and that is why we see constant increased KE in the graph.

The FInal stage shows the mobile state after the rebound.