It explains how the contact between track link and ground works in RecurDyn Trank LM toolkit. It also shows modeling mistakes case. After understanding this document, you will not make same mistake.
There is two method to define contact between track link and ground. They are
1. define road data
2. using track to surface contact
This article show the case of #2, but the software algorithm is same.
After defining track to surface contact the model looks like below.
if you open the property of track link, you can see "Shoe point", and "Grouser Mesh" as shown below.
There are two kinds of contact functions for ground contact. The one is hard ground contact, and another one is soft ground contact. The hard one is same with other rigid body contact, and soft ground contact is used for contacting with soil, etc.
at here,
"Shoe point" works with hard ground contact.
"Grouser Mesh" works with soft ground contact.
You can define the profile of grouser. If you check on 'shoe' at any point, it would be used for contact with ground. It changes data in shoe point automatically.
if you do not change anything, the default value of 'Shoe Point' will be like below. For your reference, I added the column of profile number.
According to the X, and Y value, the shoe point is define at grouser profile #8, 10, 11, 13, 15, and 19.
At here, we need to understand the meaning of Z. This Z means the point in depth direction.
Because the default value of 'Grouser Width(Wg) is 500. It has two point at +250, and -250.
It means that there are contact points at each end of link in depth direction.
In general, ground is much wider than the depth length of track link. It works correctly.
"For the practical usage, it is recommended to 'reset' shoe point, and select(check-on) shoe in the profile. It may fit the size of your product. If you select one point at profile, two grouser shoe points will be created at the two ends in depth direction. If you like to add more, you can add point manually as show below."
For the learning purpose, there is users, who use small box, or sphere to contact with track link as show below. At here, the small box is created by clinking two point in XY plane.
if you see this model in ZX plane (short key is Shift+Z), you can see that the depth of box is shorter than the one of track link. If you use default value, the contact may not work, because there is no contact points.
It will be natural to make the ground larger than link. Nevertheless, let me add additional contact point in the middle point of depth for the profile point #10, and #11 to show how it works.
The contact works like below.
the case of sphere instead of box.
Additionally, we need to know how the contact works for the soft contact.
As it is written above, "Grouser Mesh" works with soft ground contact.
Its default value is like below.
To achieve soft soil contact, it requires more contact. It uses patches instead of points.
"In the practical usage, the segment number would be bigger than 2."
We can refer to RecurDyn's help at http://www.functionbay.co.kr/documentation/onlinehelp/default.htm#!Documents/grousermesh.htm
Now, you can define contact between track link, and ground correctly.