Mid-cable objects are additional objects that can be placed along a cable span to simulate real-world scenarios.

Neara supports the modelling of 4 different types of mid-cable objects that attach to a single cable of a span:

You can visualise and perform various dynamic analyses such as Finite Element Analysis (FEA) on constructions with these mid-cable objects attached.

Neara also supports the visualisation of spreaders:

To model one of the 4 single cable mid-cable objects, you must first add a new object type entry and specify it's properties.

Click the Library menu from the menubar and select Mid-Cable Objects:

The Mid-Cable Object Library will open:

Create a new entry and in the Type column, choose between marker ball, tiger tail, vibration damper, or rota marker:

For each mid-cable object type, you can also specify the Key, Length, Mass, Wind Area and Drag Coefficient.

The Key is a user-defined name to help you easily identify the each entry you have created, by default it will be called MidCableObjectType1 however, this can be changed by clicking on the cell and updating the name.

The Length, Mass, Wind Area and Drag Coefficient are all physical parameters that are taken into account when FEA is performed on constructions with these mid-cable object types attached.

Once you have created a mid-cable object type entry (excluding spreaders, which don't require one), you can place a new mid-cable object of that type onto your desired span.

Select a span: this will automatically open the Properties tab. In the Properties tab navigate to the Spans sub-tab.

You will see a section called Mid-cable objects for span. If your span contains multiple sections, you will need to specify the section of the span (i.e. between which two poles) you want to place the mid-cable object using the dropdown menu:

At the top of the Mid-cable objects for span table, click Add new entry and assign it the type you just created:

Be sure to select the Type when adding a new entry.

You will see the object appear in the middle of the chosen span section on the first cable in the Perspective view. You can change the Cable Index to change the cable that it lies on. You can also adjust its position by changing the Position Reference and Position Offset.

Single cable mid-cable objects are accounted for when analysing conductor behaviour including cable sag and blowout, and pole loading using FEA.

At the top of the Spreaders table, click Add new entry.

The spreader appears in the middle of the chosen span section in the Perspective view:

Adjust its position by changing the Position Reference and Position Offset.

The mass, wind area and drag coefficients of mid cable objects are combined with those of the cable before analysis in the FEA engine, to determine cable sag and point tip load calculations.

In static analysis, the load of the objects is spread out over the cable as follows:

If we place five 7kg marker balls on a single cable:

The cable mass will increase by 5 ✕ 7kg = 35kg

The wind area will increase as follows:

The object drag coefficient is therefore accounted for in the new wind area, and the drag coefficient for the cable will remain unchanged.