Zero-Length Spring Creating

Question

Hi,

https://altairuniversity.com/learning-library/v_e_spring-element-type-8/

In the first example of the video on the link above, instructor has two cylinder laid in same axis. Each cylinder has one RBODY with their whole nodes. And RBODY's independent nodes weren't created using calculated nodes. 
 	Then, how did he create 'zero-length' spring as he told in the video ??

Pranav Hari · Answer

Hi Omer Faruk GUMUS Spring type 8 is a six degrees of freedom spring: three translations and three rotations. It is often used to model a joint connection between two parts. You can even assign mass and inertia to a type 8 spring if you want to study the load conditions. It depends on the application whether to use it or not. In this case we are not assigning because we are considering for a joint and the DOFs are of interest. Please check the Radioss theory manual for more details regarding the type 8 spring Thanks

Omer Faruk GUMUS_21691 · Answer

Thanks Mr. Pranav.

I actually wondered about if a mass and inertia are unnecessary just only when I create the spring by two independent nodes. In the video , the instructor could write '0' for mass and inertia in hypercrash interface. But it is not possible to set 0 value for mass and inertia in hypermesh interface , if you try, you'll get * sign with red color.  So, so zero length means that mass and inertia are not taken into consideration ???

Pranav Hari · Answer

Hi Omer Faruk GUMUS

Yes, it is created using calculate node option only

The zero length spring (type 8) is created by connecting the 2 independent node of the rigids.