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Friction and contact force calculation manually for verification

Question asked by Aysuh Mohanty on Jun 17, 2017

Hello, my problem is very simple...i have a block which i have to move over ground by pulling or pushing horizontally..attaching the screenshot of the simulation problem...u can see in the screenshot (file name: capture) force is  applied and gravity is also applied in the if as i used 3d contact force so friction and contact force comes into the picture..Now i  m providing  you below mentioned theory and equations

my target of project is to calculate this friction and contact force (IMPACT) manually in order to verify and generalize other problem. But, from the expression of the impact function the value of expressions of x,x',x1 are unknown and remaining all parameters are given for a given pair of contact.

Question: so can anyone provide me the value of expression of these three parameters such that i can calculate the impact force?




The IMPACT(x,x',x1,k,e,cmax,d) function computes collision forces as a function of displacement and velocity.






The independent variable. For a force calculation, define a displacement result to specify the x argument.


The derivative of the independent variable. For a force calculation, define a velocity result to specify the x' argument.


A positive real variable, number, or function. For a force calculation, specifies the free length of x when x < x1.

For a force calculation, the force is positive if x < x1. The force is zero if  x ≥ x1.



A nonnegative value. For a force calculation,  k is the stiffness of the boundary surface interaction. 


A positive value. For a force calculation,  e is the exponent of the force deformation characteristic. For a stiffening spring, enter  e > 1.0. For a softening spring, enter 0 < e < 1.0.


A nonnegative variable. For a force calculation, cmax is the maximum damping coefficient.


A positive real variable. For a force calculation, d is the boundary penetration at which the maximum damping cmax is applied.

Function Definition

IMPACT(x,x',x1,k,e,cmax,d) =

max(0,k*(x1 - x)e - STEP(x,x1-d,cmax,x1,0)*x')


x < x