Non-linear spring damper

This example shows how the behavior of a spring can be altered to introduce a non-linear force-displacement relationship. The complete list of commands is shown below. A description of these commands follows.

1. Retrieve the spring object using its ID:

   Spring=CS_Actuator.Find(_sid)
   

2. Create an array of real values and fill it with the pairs of values (elongation, force):

   Spring_table=System.Array.CreateInstance(float,7,2)
   
   #
   # LENGTH transition values
   spring_table[0,0]=0.
   spring_table[1,0]=50.
   spring_table[2,0]=60.
   spring_table[3,0]=100.
   spring_table[4,0]=140.
   spring_table[5,0]=150.
   spring_table[6,0]=200.
   #
   # Spring Stiffness
   spring_table[0,1]=-100000.
   spring_table[1,1]=-10000.
   spring_table[2,1]=-1000.
   spring_table[3,1]=0.
   spring_table[4,1]=1000.
   spring_table[5,1]=10000.
   spring_table[6,1]=100000.
   stiffness = CS_PointsTable(spring_table)
   spring.SetTable(stiffness)
   

   In this command, 7 represents the number of rows and 2 for the number of columns. The first column gives elongation and the second, the corresponding force value. This command generates a PointsTable assigned to the spring, as shown below.

   

   Each spring object in the Mechanical GUI is actually a combination of a spring and a damper. The GetDamper method enables you to retrieve the damper object on a given spring, as shown below.

   

3. Introduce a table to define a non-linear force velocity relation:

   Damper=spring.GetDamper()