Understand the Shaft Geometry: Define the core shaft (material and diameter) and the flexible outer casing, considering the bend radius and material flexibility.

Choose CAD Software: Use software like SolidWorks, Autodesk Inventor, or PTC Creo that supports flexible components and simulations.

Model the Shaft: Create the core shaft as a cylinder, then add the flexible outer casing, accounting for thickness.

Simulate the Bend: Use the CAD software to bend the shaft, setting the bend radius and angle, and simulate how the shaft deforms.

Assign Materials and Simulate: Assign material properties to both the core and casing, then run simulations to check stress and deformation under load.

Adjust and Refine: Modify the model based on simulation results, ensuring proper performance under operational conditions.

Export and Document: Export the model in suitable file formats and document the design parameters for manufacturing.

trying to model a flexible drive shaft with a multi-layer wire configuration. Since you're encountering issues when using the "flex" feature to model the bending of the shaft, there may be several factors affecting your model.

Check for Proper Definition of the Bending Radius:

When specifying a bending radius, especially for a complex model with multiple coil layers, ensure that the parameters are correctly set to accommodate the total geometry of the drive shaft.

If your model is failing to bend, it's possible that the software is interpreting the geometry of each individual coil in a way that conflicts with the bending radius.

You might want to divide the bending into smaller sections (sub-components), particularly if you're dealing with a high degree of flexibility.

2. Simplify the Initial Model (for Testing):

As a first step, simplify the model to see if it can bend in a straightforward configuration (such as a single coil or layer). This can help isolate whether the issue is related to the complexity of the multi-layer wire configuration or the bending feature itself.

Gradually add complexity (like more layers or wires) to see where the model fails to bend.

3. Check Material Properties and Constraints:

Verify the material properties (e.g., elasticity, stiffness, and other mechanical properties) in the CAD software for the flexible shaft. If these properties are incorrectly defined or overly rigid, they may not allow the shaft to bend properly.

Also, review any constraints or fixed points that may prevent the model from bending freely. Make sure that the bend is being applied correctly to the whole assembly, not just to a specific segment.

4. Use Additional Features for Wire Coiling:

If your software supports specific wire or coil modelling features, make sure you’re using those instead of just the general "flex" feature. Some CAD tools have specific wire coiling or spring features, which can help define the layers more precisely.

Ensure that the direction of each coil layer is correctly modelled to achieve the intended helical pattern.

5. Verify the Bending Methodology:

If you're using an advanced bending simulation or tool (like "flex" in your software), check if the bending tool supports multi-layer flexible models or if additional settings need to be configured to allow for bending in a multi-layer setup.

Some CAD tools have limits on how much bend can be applied to flexible bodies, and this could be a factor at 180 degrees. You may need to break down the bend into smaller steps (e.g., 90 degrees at a time) and check if this approach works.

6. Check for Software-Specific Limitations:

Depending on the software you're using (e.g., SolidWorks, CATIA, Autodesk Inventor, etc.), there might be limitations on how flexible components can be bent or simulated.

Some CAD tools may not fully support complex multi-layer flexible models with significant deformation, and additional plug-ins or alternative bending techniques might be required.

7. Use Finite Element Analysis (FEA):

If your software has an FEA module, you could try running a basic simulation of the bending using FEA to test if the material and structural setup are appropriate for the deformation you need. This may provide additional insights into the reasons the "flex" feature is not working as expected.

8. Consult Documentation/Support:

It's also a good idea to refer to the official documentation or user guides for your CAD software. Often, complex modelling issues are addressed with specific workflows, especially when it comes to flexible components.

Alternatively, you may want to contact the software's technical support team for specific advice on how to handle multi-layer flexible shafts in the bending configuration.