01 Jul Structural Weldments for Aerospace Vibration Testing
Structural Weldments for Aerospace Vibration Testing
Integrating Design, Fabrication, and Quality to Meet Program-Critical Requirements
In aerospace applications, ground testing is critical when validating system integrity prior to flight. Vibration tests enable engineers to simulate the operational stresses components will encounter in service.
These structural test fixtures must not only support high loads, but also preserve tight tolerances and dimensional integrity under extreme dynamic conditions. For projects like these, success depends on more than just fabrication skill — it requires integration across design interpretation, part production, welding, inspection, and program responsiveness.
Engineering Considerations in Fabrication
Fabricating this type of structural assembly requires more than welding capability alone. From the outset, the project demanded close coordination between design intent, fabrication sequencing, and dimensional control to ensure the final structure would maintain integrity under dynamic loading conditions.
Key factors included:
1. Understanding Load Paths and Test Objectives
Effective fabrication starts with understanding the functional role of the weldment within the qualification program. In this case, alignment with the vibration test profile and anchoring strategy was critical to ensure the structure could deliver consistent, valid test results, without introducing test artifacts or unexpected structural behavior during repeated cycles.
2. End-to-End Fabrication Process Control
Before the main weldment could even be tacked together, numerous adjacent processes had to be executed with precision. These included:
- Saw cutting of structural steel members
- Waterjet cutting of mounting and interface plates
- 3-axis CNC milling of flat and prismatic surfaces on both structural shapes and plate stock
- CNC turning of sleeves and bushings
- Complex 5-axis machining of separable payload interface components — including tight-tolerance features on both aluminum and steel materials
This complete suite of in-house capabilities enabled efficient coordination between upstream part production and downstream assembly, avoiding reliance on outside vendors for critical path items and preserving overall schedule integrity.
3. Fabrication Sequencing and Weld Strategy
Large structural weldments are inherently susceptible to residual stress and distortion, particularly when working with mixed thicknesses and complex geometries. To address this, the team employed a carefully planned weld sequencing strategy to:
- Minimize thermal distortion
- Preserve flatness and squareness
- Maintain part-to-part repeatability and fixture alignment
These controls are especially important when test data visibility is high and fixture variability could impact test validity.
4. Precision Fixturing
Custom welding fixtures were designed and fabricated in-house to fully support the structure during both tack-up and final welding operations. These fixtures allowed accurate, repeatable alignment across multiple interfaces, including the vibration table hardware and the customer’s test article. This ensures clean integration and accurate data capture.
5. Weld Quality and Dimensional Inspection
Given the structural role of the assembly and the sensitivity of the test environment, weld quality was non-negotiable. The team implemented:
- In-process visual and dimensional checkpoints
- Final part inspection with documented verification
- Verification of GD&T-defined interfaces and critical mounting features
Only powder coat finishing was outsourced — every other element of part production and inspection was managed internally, providing maximum control over quality and turnaround time.
6. Adaptability to Program Requirements
Program-critical hardware often comes with changing design inputs and compressed schedules. This project required flexibility and real-time collaboration to accommodate late-stage design revisions without impacting downstream quality or delivery.
By controlling all manufacturing steps, the team was able to adjust quickly while preserving part integrity, repeatability, and traceability.
Conclusion
While there are certainly other vendors capable of producing aerospace vibration test fixtures, delivering a project like this successfully requires more than welding alone. It demands control over multiple adjacent processes — machining, cutting, fixturing, inspection — and the ability to coordinate them seamlessly under program pressure.
KL Engineering’s integrated approach eliminates reliance on third parties for critical-path components, enabling faster iteration, higher consistency, and greater accountability from start to finish.
Let’s Build the Right Solution—Together.
At KL Engineering, capability and flexibility unite to serve one purpose: your goals. We don’t believe in one-size-fits-all. Instead, we tailor every project to fit your unique needs, seamlessly aligning with your processes and priorities. Ready to move forward with a partner who adapts to you? Contact us today to get started on your next project.