Creating a joint revolute for a vehicle axle

Rahul_P1

Hello Community,

I'm struggling with creating constrained_joint_revolutes. I want to define a rotational movement about the y-axis between two rigid bodies. I know that I have to use the option 'fe joint' to create the joint revolute, but somehow it's not working. There are two pictures attached where you can see the rigid bodies that are necessary for my joint_revolute and how it should actually look like. We are using LsDyna as solver, so the solution has to be compatible with it. It would be great if anybody could give me a step by step tutorial or even better name a book or paper in which an easy instruction can be found. Thank you guys in advance.

Edit: I've already read a lot in the hyperworks manual but without any succes. And google couldn't help me either.

Rahul_P1

oleg,

If you already read the procedure in HyperWorks Desktop Applications > HyperMesh > HyperMesh Solver Interfaces > LS-DYNA: HM-4610: Using Curves, Beams, Rigid Bodies, Joints, and Loads in LS-DYNA

then, the problem is perhaps with the generation of coincident nodes and the order of picking these nodes, you need to create a pair of coincident nodes which define the axis of rotation and select these nodes one by one first one coincident pair then the other i.e. While picking the nodes please ensure that the coincident nodes that you pick should belong to different rigid bodies.

For e.g. node 1 and node 2 to be coincident node1 should belong to rigid body A and node 2 should belong to rigid body B (This is how LS Dyna requires the joint to be defined), similarly the same should be followed for node 3 and node 4.
So as an LS Dyna requirement node 1 and node 3 should belong to rigid body A and node 2 and node 4 should belong to rigid body B.

Joints
All LS-DYNA joints are created by clicking Tools > Create Cards, or by clicking Mesh > Create > 1D Elements > Joints. They are organized into a component collector with no card image.
Unlike other 1D elements, you do not specify the LS-DYNA joint type from the 1D Elements > Elem Types panel. Rather, specify it in the panel used to create it, the 1D Elements > fe joints panel.
The FE Joints panel has the property= selector. As a LS-DYNA user, you can disregard this selector. If the HyperMesh user profile is loaded, the panel also has the orientation option. As a LS-DYNA user, you can disregard this option also.

Coincident Node Picking
For LS-DYNA joints, the nodal points in the nodal pairs should coincide in the initial configuration. The coincident picking option can be turned on by clicking Preferences > Graphics. It allows you to graphically select a desired node from a stack of coincident nodes. This option also supports coincident picking for elements, loads, and systems.

Create Coincident Nodes
Create a node 'like' an existing node from the Nodes panel in the Geom page. Click as node, select a node in the graphics area and then click create.

Rahul_P1

Thanks for your response,

but I always get the error message in LsDyna: Node 1 in Rigid Body A and Node 2 in Rigid Body B are not coincident. Their coordinates have to be adjusted. I create Nodes using the Geometry panel by clicking on 3 nodes of the inner circle of the purple part above, to create an additional node for the circle center. Then I translate them in y-direction. After finishing this I create node-sets in which I put 2 nodes for rigid body A and 2 nodes for rigid body B. Then I move them to be constrained extra-nodes for the rigid body A and B. After this I create a Joint_revolute by clicking the panel 'Tools -> Create Cards -> Constrained Joint Revolute' and I'm quite sure that I have the right order. Well joint is created but LsDyna is not solving. I really need to know what steps I have to consider by creating this joints. Do I have to put mass on the nodes? Do I have to create two single tria elements as you can see in the second picture above? And how do I create coincident nodes for LsDyna in Hypermesh?
Thanks guys for your time.

Edit: I started working with Hypermesh(v11.0) and LsDyna(ls971 R4.21) in January this year and I taught it myself by reading and trying. So I need an easy explanation.

Rahul_P1

Oleg,

Also see HyperWorks Solvers > RADIOSS > Multi-body Dynamics Analysis > RD-4010: Dynamic Analysis of a Slider Crank with a Flexible Connecting Rod

Step 5: Creating Joints

Rahul_P1

Hi guys,

I did this tutorial 'HM-4635: Checking Penetration, Creating Joints and Checking Minimum Time Step'. But when I tried to create the revolute joint there was not coming up the coincident node picking window. Why is it not working? The spherical joint in the task before didn't make any problems.

Rahul_P1

Oleg,

I am afraid I am able to select the nodes easily here, you can try deleting the settings files (Forum » Modeling (Preprocessing) » HyperMesh » How to delete settings files) and try again