1st order to 2nd order conversion

Actually, it is usually recommended that the RBEs are connected only to the corner nodes of your model. So you should be okay.

Hello Edwin Goei,
Thank you so much for your reply.
If it possible can you please share any reference for this.
This information is available in any nastran document ?

Thanks and regards,
Thanga Pandiyan.

Unfortunately there isn't documentation on this; it's just a general recommendation. You can check with your team to see what is your company's best practices. It must be noted that you could connect RBEs to midside nodes and Nastran will not give you an error. However, stress in the elements around RBE3s may be higher if midside nodes are used to define the RBE3s. It is for this reason the RBE is usually not recommended to be connected to midside nodes. For modeling convenience, you can include midside nodes, but if you are concerned about local stress, using only corner nodes may lead to smoother stress distribution.

Unfortunately there isn't documentation on this; it's just a general recommendation. You can check with your team to see what is your company's best practices. It must be noted that you could connect RBEs to midside nodes and Nastran will not give you an error. However, stress in the elements around RBE3s may be higher if midside nodes are used to define the RBE3s. It is for this reason the RBE is usually not recommended to be connected to midside nodes. For modeling convenience, you can include midside nodes, but if you are concerned about local stress, using only corner nodes may lead to smoother stress distribution.

Thank you Edwin Goei.