2D Simulation of the oblique impact of the disk on the wall

Introduction

Some movies about the 2D simulation of the oblique impact are shown.
The disk collides the wall in the gravitational field with various incident angles.
The disk and the wall are expressed by mass-spring models using randomly placed 2400 mass points.
All mass points are binded with nonlinear springs and the force operating
on the i-th mass point is

,
where m is mass, g is the gravity constant, and k_* is the spring constant
replaced by k_d in the disk and by k_w in the wall.
k_b is the constant of the nonlinear term,
delta is relative length from the natural length of the spring, eta is the damping constant,
and v_i is the velocity of i-th mass particle.
The interaction between the disk and the wall is an exponential function
of the distance between them.

We choose the values:
g=10^{-6}mc^{2}/R, k_d=1.0*mc^{2}/R^{2}, k_w=2.0*10^{-2}*mc^{2}/R^{2}, k_b=10^{-3}*mc^{2}/R^{4},
and eta=0, where m, c, R are mass, the velocity of sound wave,
and the radius of the disk, respectively.

The thickness and the width of the wall is 2R and 8R. Both sides are fixed.

Movies

tan gamma = 2.0

tan gamma = 10.0

Results

The graph below is the case when the impact velocity is 0.1c and
k_w=10(scaled), k_d=1(scaled)(wall is harder than disk).