Help for newbee Kangroo cable definitions

by tonguc salgar

Jun 20, 2011

Hello Everybody

 

First of all I must express my feelings about Grasshopper and kangaroo : Amazing work that will change the shape of design architecture and engineering.

 

As for my need of help. After many times of trial and error I am afraid  I will not be able to master kangaroo without good knowledge of civil engineering. So I am asking for help.

 

I am on to a concept drawing of a factory shed which I like to design with a suspended cable system. But I cant define any suspended cable system no matter hard I try. Does anyone has any pre-defined grasshopper definition. I can do the rest. I need to define shape of the wire rop, so I can be sure to have neccesary clearance from the ground. here is my pre-design.

 

Thank for any help

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  • jjsolly

    The sag of the cable will form a catenary under uniform loading (which it looks like you have)..

     

    The final sag of this catenary can be chosen by you - this then determines the tension in the cable and hence it's thickness and the requirements on the surrounding structure.

     

    You do not need to use Kangaroo to form-find the cables in this roof for scheme design - they will be VERY close to catenarys.

     

    If i've misunderstood the question then I would recommend looking at the USS Wire Rope Engineering Handbook which has simple equations for the shape of cables under a whole variety of situations...

    Jun 22, 2011

  • tonguc salgar

    thanks alot for the reply. I will in to what you mention right a way. The reason I want to use kangaroo is to get fast feedback from when I made design changes. The above basic design tends to change when I get better understanding of Kangaroo and grasshopper. But to bigin with I need to solve this basic system. But You gave me new directions to follow thanks alot.

     

    Jun 22, 2011

  • Steve Lewis

    JJsolly is correct for a single curvature span you can estimate loads and geometry assuming a catenary profile.

     

    If you have a 2-way spanning cable net with or without double curvature you cannot use a catenary defintion and you will have to form-find it using a suitable iterative numerical approach that accurately models the form with the requiried equilibrium required.

     

    Jun 25, 2011