Design Challenge & Concept
Off-road utility buggies require robust spaceframes to withstand high torsional stresses during multi-terrain driving. However, shipping and storage requirements often dictate a compact footprint. This project presents a full CAD assembly of a lightweight, foldable spaceframe chassis. It collapses into a flat-pack volume while maintaining roll-over protection standards (ROPS) when deployed.
Figure 1: Spaceframe CAD wireframe sweep modeling showing cage members and bracket attachments
Mechanical Assembly & Linkages
The frame's folding mechanics rely on custom designed locking linkages and pivot joints:
- Linkage Kinematics: Designed dual-pivot joints that enable the roll cage section to fold down into the main passenger compartment.
- Locking Pins: Quick-release pin structures lock the frame segments under tension, eliminating buckling risks.
- Suspension Clearance: Double-wishbone geometry paths were plotted in SolidWorks to ensure suspension arms avoid collisions with the folded frame components.
Material Selection & Stress Modeling
To balance structural rigidity with overall chassis weight, the frame utilizes hollow circular AISI 4130 Chromoly Steel tubing. Weld joints are reinforced with steel gussets to mitigate torsional buckling during cornering.
| CAD Parameter | Structural Specification |
|---|---|
| Modeling Software | SolidWorks 3D |
| Material Class | AISI 4130 Chromoly Steel Tubing |
| Frame Weight | 62 kg (Spaceframe skeleton only) |
| Volume Reduction | 55% Volume reduction (Flat-folded) |
| Torsional Rigidity | 1800 Nm/degree |
| Safety Factor | 2.1 (Roll-over ROPS static loads) |
Structural Rendering & Fold Assembly
To check interference zones and verify component placement, a solid assembly was modeled, showing the engine bay mount plate, standard double bucket seats, and suspension attachments:
Figure 2: Complete CAD assembly showing seating layouts and member folding axes
Space Savings Impact
When folded, the chassis volume is reduced by 55%, allowing two fully compiled buggy frames to be transported within the cargo bed space of a single standard utility truck.