## General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

#### What is the difference between Elastic Support & Ground-body Spring connection?

• Rameez_ul_Haq
Subscriber
And also, which one should be used where? An example for each case will be very much appreciated. Thank you.n
• Rameez_ul_Haq
Subscriber
Anyone on this?n
• Ashish Khemka
Forum Moderator
• Rameez_ul_Haq
Subscriber
Thank you for attaching a link, but the content in that link unfortunately doesn't answer what I was looking for.nThe forum says that the foundation stiffness for an elastic support 'offers stiffness per unit area' but the foundation stiffness in elastic support is in the units of N/mm? for a face of a solid. The forum is dedicated for an APDL command to implement the elastic support, whereas I want to know the difference between if I will add the elastic support, as compare to if I add a spring support to the same face. nThank you.n
• Rameez_ul_Haq
Subscriber
Need help on this one please?n
• peteroznewman
Subscriber
nIf a Face has 64 nodes on it, then there will be 64 springs to ground created for the elastic support.nIf you add a spring to ground to the same face, there will be one spring created with a rigid spider to the face. However, the spider can be changed to deformable.nThe elastic support is always perpendicular to the face. A spring attached to a face can go in any direction.nThe elastic support spring rate is N/mm^3 while the spring rate is N/mmnThe spring can have damping, but the elastic support cannot.nThe spring can have a preload, but the elastic support cannot.nThe spring can be defined between two points, so it has a length. The elastic support is only defined as a spring rate.n
• Rameez_ul_Haq
Subscriber
the elastic support makes the scoped face as rigid or deformable? Is there a way to change that?nHow can I input a correct foundation stiffness for the elastic support? Can you give an physical example for me of each to clearly percept in which case elastic support will proof to be fruitful and in which case spring connection can do the work?n
• peteroznewman
Subscriber
nRigid and Deformable only applies to a Spring. It doesn't apply to Elastic Support. Elastic Support is like Deformable in that no extra stiffness is added to the model in addition to the spring rate. nElastic Support is simply a a spring rate per unit area. If you had a face with an area of 16 mm^2 and you wanted a spring rate for the whole face of 2 N/mm then you would use an elastic support with a spring rate of 32 N/mm^3. If you edit the geometry and cut the face area in half, the elastic support will end up being equivalent to a single spring of 4 N/mm.nHere is a good example of an elastic support: https://forum.ansys.com/discussion/19500/how-to-model-a-beam-on-elastic-foundationn