Elastomer simulation (elasticity)

Elasticity ..... Forget .... But it's okay , Physics is better than me , Push it by hand

Elastic force

I learned Hooke's law in junior high school F=-kx , According to the figure below , It becomes $F=k(y-l)$, among L It's the balance position

If only the spring , If you give a force, it will vibrate all the time , We assume that there is air resistance F2（ Opposite to the direction of speed ）, And the resistance coefficient is c, Then there is the stress diagram as follows , And $F_2=c\times v^2$：

Get the resultant force $F=k\times (y-l)-c\times v^2$, Suppose the mass of the particle m, There is motion acceleration a=F/m

Two dimensional elastomer

Only consider the object in the middle , The force direction is from 4 Two dimensional points determine

Then write it as a vector , It's very simple at the back , No derivation