TEKNOFEST Electromobile: Door and Lock Mechanism Design
DfM-driven door and latch system design for a competition electromobile — assembly compatibility, weight constraint management, and cross-team interface coordination
01 Problem & Context
The TEKNOFEST electromobile competition imposes strict dimensional and mass constraints across all vehicle subsystems. Designing a door and lock mechanism that satisfies chassis interface geometry, structural load requirements, and assembly manufacturability — while remaining within team-allocated weight budget — requires coordinated interface management with parallel design teams. Interface dimensions are subject to revision throughout development, creating a dependency between door design progress and chassis finalization. This project is in active development.
02 Objectives & Constraints
- — Design door and lock mechanism geometry in SolidWorks achieving full dimensional compatibility with the existing vehicle chassis
- — Stay within the door-lock unit mass budget allocated by the team-level weight management process
- — Satisfy structural requirements: door panel resistance to lateral loads without permanent deformation; latch retention under competition dynamic conditions
- — Ensure all components are manufacturable with available club workshop tooling or standard outsourcing routes (DfM constraint)
- — Establish and maintain interface control with chassis and body panel teams: freeze mating surface dimensions before detailed geometry is committed
03 Process
Process
Project Context
The AGÜ Automotive Club is building a competition vehicle for the TEKNOFEST Electromobile category. The vehicle is developed by parallel subsystem teams — chassis, powertrain, body panels, door-lock, and electronics — each with independent design scope and shared interface obligations. The door and lock system interfaces with chassis frame geometry, body panel surfaces, and vehicle entry/exit functional requirements.
Requirements and Interface Definition
The design process began with translating vehicle-level competition requirements into door-lock unit specifications:
- Structural: door panel must withstand specified lateral load without permanent deformation; latch mechanism must retain under vehicle dynamics conditions encountered during competition use
- Mass: stay within the mass budget allocated by the team-level weight management process
- Assembly: all components must be installable using club workshop tooling or standard fasteners; no bespoke tooling
- Interface: door attachment geometry must conform exactly to chassis mating surfaces defined by the chassis team
Interface control was the first design gate: a cross-team checkpoint was established to freeze chassis mating surface dimensions before door geometry advanced beyond concept stage. This prevented a common failure mode in parallel team design — detailed door geometry developed against a chassis that subsequently changes, requiring geometry rework.
Design Development in SolidWorks
The door system is modeled as a full SolidWorks assembly:
- Outer panel — sized for dent resistance under lateral contact; geometry follows body panel surface curvature
- Inner structural frame — primary load-carrying structure; transmits hinge and latch reaction forces to chassis attachment points
- Hinge brackets — designed for fatigue-tolerant attachment; clearance for installation sequence
- Latch mechanism — positive retention design: no single-point failure mode releases under competition dynamic conditions
- Striker plate — chassis-mounted mating component; position determined by interface control document
Each component is modeled with explicit manufacturing constraints incorporated from the first geometry iteration:
- Sheet metal bend radii compatible with available club forming equipment
- Fastener clearance for installation with standard tooling (no access restrictions)
- Weld joint access at any frame joints requiring fusion welding
Mass and Structural Tradeoffs
The primary design tension is mass reduction against structural section adequacy. The load path analysis clarifies the tradeoff:
- Door panel: carries no primary structural load — load is transmitted through hinge brackets and latch to the chassis frame. Panel thickness is sized for dent resistance and surface appearance, not structural contribution. This is the primary mass reduction opportunity.
- Inner frame: is structural — section depth sized to carry hinge reaction moments and latch retention forces without exceeding material yield. Section is concentrated at load introduction points (hinge attachment, latch housing), with reduced section in the non-load-carrying spans.
This load-path-informed sizing approach targets mass reduction where the panel has no structural role, while preserving adequate section where it does.
DfM Review Process
Manufacturing constraints are evaluated at each geometry iteration before the SolidWorks assembly is updated:
- Bend radius check against available forming equipment
- Fastener clearance verification for installation sequence
- Weld access review for any welded joints
- Material thickness consistency with club stock
Components failing DfM review are flagged for geometry revision before the assembly is advanced. This keeps DfM issues from accumulating late in the development cycle.
Current Status
Active development. Initial assembly geometry produced. Interface control document with chassis team in progress. Structural verification via SolidWorks Simulation planned for completion once door geometry is stable.
04 Challenges & Solutions
Designing door geometry that conforms to a chassis defined by parallel teams, where interface dimensions remain subject to revision throughout the development cycle
Established a chassis interface freeze checkpoint before door geometry advanced past concept stage — mating surface dimensions locked as a prerequisite for detailed design. This decoupled door design progress from ongoing chassis revisions and eliminated late-stage geometry rework from interface drift
Meeting mass budget while maintaining sufficient structural section for latch retention force and door panel stiffness under lateral load
Applied load-path-aware section sizing: door panel carries no primary structural load (load path runs through hinge brackets and latch to chassis frame), so panel thickness is sized for dent resistance, not structural contribution. Section depth concentrated at hinge and latch attachment points where bending moments are highest
05 Results & Outputs
- ✓ Door and lock mechanism assembly model under active development in SolidWorks; initial geometry produced
- ✓ Interface control checkpoint established with chassis and body panel teams; mating dimensions documented
- ✓ DfM review cycle ongoing: sheet metal bend radii, fastener clearance, and weld joint access evaluated at each geometry iteration
06 Measurable Impact
Competition deadline: TEKNOFEST 2026 (active development)
07 Lessons Learned
- → In parallel multi-team vehicle design, interface control is a hard design dependency, not a coordination formality — establishing mating dimension freezes explicitly and early prevents compounding late-stage rework when adjacent subsystems converge
- → DfM analysis is most cost-effective at the concept stage: evaluating bend radii, fastener clearance, and weld access during section sizing and profile selection eliminates rework cycles that emerge when manufacturability is assessed only after geometry is committed