Using SOLIDWORKS Motion to Accurately Model a Disc Golf Basket Chain

In our previous article, the disc golf basket was modeled in SOLIDWORKS using a top-down approach, weldments, and a skeleton sketch in the assembly to mate all the components together. By referencing the geometry in this assembly, I will model a chain ensuring the links hang from the frame as intended.

This task will be accomplished using in-context assembly features, the move/copy body command, and a curve pattern. With the help of SOLIDWORKS Motion Analysis, I’ll simulate the real-life shape of the chain under gravity and compare it to my initially assumed shape.

In-Context Assembly Modelling

In SOLIDWORKS, in-context assembly modeling refers to creating and modifying parts within the assembly file instead of individual part files. One major benefit of modelling in the assembly file is the ability to establish relationships between parts based on their geometry. Changes to one part in the assembly will automatically update linked parts.

In some scenarios, it is easier to model inside the assembly for spatial reasons. One example is pipe routing and electrical wiring, where connection points in 3D space dictate the start and ending points of wires and pipes. A couple of common in-context assembly modeling methods include creating a new part in an assembly and editing existing components in an assembly.

Assembly sketch created with in-context relations

Given that the disc frame and chain ring are defined in the assembly, I modeled the chain in context to leverage that geometry and ensure it is hanging from the correct points.  As shown above, the green and magenta sketches were sketched such that their end points are linked to components in the assembly. These sketches represent my assumption of the chain’s shape, but we’ll see how accurate that is later.

Using Move/Copy Body

The first chain link is modeled by sweeping a circle profile along a slot path. Creating a profile sketch and a path sketch requires two planes and two sketches, which results in putting a ton of miles on your mouse and wrist. Instead, I copied and translated the first link using the Move/Copy Body command.

Two chain links created with the Move/Copy Body command

This command allows users to translate, rotate, copy, and constrain solid or surface bodies. The benefit of this approach is that the copied chain link is linked to the first link… making it a chain reaction. Any changes made to the first link will automatically propagate to any copied links. This technique is useful to manipulate bodies in a multi-body part environment.

Leveraging Curve Driven Patterns

Now that a pair of 90-degree alternating chain links are modelled, the next step is to pattern these two bodies along the chain-shaped sketch. The Curve Driven Pattern is versatile in that it accepts patterns along a planar or 3D curve, and the pattern can be defined using a sketch segment, edge of a face (solid or surface), on an open curve, or a closed curve (such as a circle). I am basing mine on a curve.

Setting up a Curve Driven Pattern with different Alignment options

Whenever you are patterning or mirroring in SOLIDWORKS, select the right option for your scenario, whether it’s features and faces or bodies, to achieve the desired result. In the Curve Driven Pattern Property Manager, the Alignment method option dictates whether the patterned features/bodies align to the seed or align tangent to the curve.

Validating Assumptions Using SOLIDWORKS Motion Analysis

Simulations are often conducted to answer specific questions prior to real-world testing, thereby reducing the number of prototypes required to achieve the desired performance. Typically, simulations answer specific questions. What is the final shape of the chain under the influence of gravity alone? What is the estimated time it takes the chain to settle from an initial position?

The Motion Analysis tool included in SOLIDWORKS Simulation licenses is the ideal solution to answer these types of questions. It is a true physics-type analysis software built right into SOLIDWORKS, used to solve kinematic problems by calculating forces, velocities, accelerations, torques, and contacts between components.

Using SOLIDWORKS Motion to simulate the disc golf chain

This brings us back to my initial assumption: how well did I predict the shape of the chain?

Using Motion Analysis, I defined the contact interactions between the chain links and applied gravity to the study. To accelerate convergence, I increased the damping and friction parameters between chain links. After 10 seconds, the chain does not fully reach equilibrium but has settled sufficiently for a meaningful comparison. The results are below for your review.

 SOLIDWORKS Motion study result (Left) vs assumed chain shape (Right) 

Looking to use SOLIDWORKS Motion Analysis for a similar study to improve your designs? Enroll in a formal training class here.