Force Reactions

[smithson1984]

Hi Folks,

I am using ANSYS Mechanical and have a question regarding force reactions. Is there a way to plot how a force is distributed over a fixed support?

To give a bit of background to my specific problem, I work for a Naval Architect consultancy and I am designing a transit cradle intended to support a small vessel. The intention being that the small vessel and transit cradle will be placed on a barge for transportation. I have a surface model of my transit frame with the appropriate weights applied. The design is such that the load transferred through to three large box section girders. I have applied a fixed support to each of these girders. I can then easily find the global force reaction on each girder but I am wanting to know how this load varies as you progress along the girder to ensure that it complies with deck loading rules.

Any help or advice would be greatly appreciated!

Many thanks,

Ian

 

[L_K]

Could you split the large surface to smaller segments and define fixed support for each?

 

[L_K]

Or integrating surface stresses.

 

[smithson1984]

Hi L K,

Thanks for the response.

I think splitting the faces may be the best solution to this. I was hoping that I could get a single plot or graph which would show the distribution rather than having to have several/many different force reactions.

In terms of integrating the surface stresses would you be meaning a stress probe? Or perhaps a just a von mises plot? I think my model is not ideally set up but I am finding the stresses are c. zero because of the fixed support.

Thanks again,

Ian

 

[L_K]

I meant for example if you look at the normal to surface stresses of some segment of fixed support, by integrating
the stress values over area you should get force reaction in that direction.

However, this is not very easy to do in Ansys. If you are looking at the fastest and easiest way, splitting the
boundary condition is best.

 

[L_K]

There are also other possibilities. If you are willing to share some pictures of the model and said boundary condition,
that would help.

 

[D_UK]

Ian

One option would be to define remote constraints about the centroid of the support patch. These allow output of the reaction forces and moments which could be used to calculate the (triangular) pressure distribution.

Alternatively, set up contacts between the hull and support frame and output the contact pressures directly.