The goal of this document is to define the test and procedure for the boattail qualification under axial compression.
The purpose of this test is to ensure that the manufactured part meets structural requirements by verifying that it withstands the specified load. This document aims to standardize the methodology, define pass/fail criteria, and document the procedural steps.
The boattail is a carbon-fiber-reinforced component whose compressive strength is a function of the number of carbon layers applied during manufacturing.
This TSP will not include simulations; the focus is exclusively on the physical test.
This document serves as a Qualification Test Specification and Procedure (TSP).
The qualification stage seeks to demonstrate that the current design meets the mechanical requirement through empirical validation.
The key question addressed by this test is:
"Is the current number of carbon layers sufficient to resist the specified axial compression load?"
The test will be carried out using the EPFL tensile/compression testing machine under controlled lab conditions.
The objective of the test is to apply a compressive axial load of 2000 N to the boattail and observe its mechanical response under repeated loading.
The test will be performed on the Zwick 100 kN testing machine in compression mode.
The procedure consists of:
This procedure allows verification of the structural integrity under a realistic and repeated load condition.
The loading sequence is essential for validating the boattail's resistance to repeated compression. Therefore, the order of operations must be followed strictly as described in the procedure (apply → hold → release → repeat).
The test is considered passed if all of the following criteria are met:
Any sign of structural failure, irreversible deformation, or non-compliance with these conditions will result in a test failure.
The test will be performed at EPFL using the Zwick 100 kN universal testing machine located in the mechanical testing lab.
The test will involve members of the Structures sub-team.
Testing is scheduled ASAP, depending on the availability of:
All safety procedures and lab rules will be followed during the setup, testing, and disassembly phases.
| Sub-System | Part Name/ID | Type of Part | Version ID |
|---|---|---|---|
| Structure | Boattail | Flight hardware | [TBD] |
| Structure | Boattail | Test sample (model) | [TBD] |
Note: Only one flight-representative test sample will be tested. Additional backup units may be prepared if available.
| Packed ? | Equipment | Packed in | Packed by |
|---|---|---|---|
| ☐ | Boattail specimen (flight-representative) | Hand carry | TBA |
| ☐ | Protective gloves | Hand carry | TBA |
| ☐ | Flat compression plates | Installed | EPFL Lab |
| ☐ | Zwick 100 kN testing machine | — | EPFL Lab |
| ☐ | Phone or camera for documentation | Hand carry | TBA |
| ☐ | Notebook + pen | Hand carry | TBA |
| ☐ | Laptop with Zwick software (if needed) | Lab station | EPFL Lab |
| ☐ | Plexiglass safety shield (transparent panel) | Loose | TBA |
The test will be performed using the Zwick 100 kN universal testing machine, configured in compression mode.
The Zwick machine and its instrumentation do not require manual mounting or calibration by the operator on the day of the test (unless stated otherwise by the lab technician).
The test will be conducted in the EPFL Mechanical Testing Lab, where the Zwick 100 kN machine is located.
| Responsible for: | Name |
|---|---|
| Equipment Checklist, Data Gathering | TBA |
| Preparing the test on-site | TBA |
| Documenting/Reporting | TBA |
| Safety | TBA |
| Safety Concern | Probability | Impact | Severity | Mitigation | Post-Mitigation Probability | Post-Mitigation Impact | Post-Mitigation Severity |
|---|---|---|---|---|---|---|---|
| Test part does not withstand load | Medium | Test failure | Medium | Verify part layup and dimensions before test | Low | Medium | Low |
| Improper alignment of the part | Medium | Invalid results | Medium | Visually inspect alignment before launching compression | Low | Low | Low |
| Part damaged during setup | Low | Rework needed | Low | Handle with gloves and position on flat plates carefully | Very Low | Low | Very Low |
| Fragment projection from carbon failure | Low | Eye or facial injury | High | Use protective plexiglass shield between operator and specimen; wear safety goggles | Very Low | Low | Low |
| Safety Concern | Probability | Impact | Severity | Mitigation | Post-Mitigation Probability | Post-Mitigation Impact | Post-Mitigation Severity |
|---|---|---|---|---|---|---|---|
| Pinch or crush injury during setup | Medium | Minor hand injury | Medium | Keep hands clear during platen movement, use gloves | Low | Low | Low |
| Sudden failure of part under load | Low | Flying debris | Medium | Wear safety goggles, maintain safe distance during loading | Very Low | Low | Very Low |
| Unexpected machine behavior or failure | Very Low | Equipment damage | Medium | Ensure operator is trained and machine is calibrated | Very Low | Very Low | Very Low |
| Done ? | Task | Time | Operator |
|---|---|---|---|
| ☐ | Transport boattail to testing lab | 10m | TBA |
| ☐ | Prepare and clean compression plates | 5m | TBA |
| ☐ | Power on and initialize Zwick machine | 5m | TBA |
| ☐ | Load test protocol into Zwick software | 5m | TBA |
| ☐ | Review safety protocols with team | 5m | TBA |
| Done ? | Step | Tool |
|---|---|---|
| ☐ | Place boattail flat on bottom plate | Gloves, Foam |
| ☐ | Align boattail visually and ensure central placement | Mirror, Eyes |
| ☐ | Lower top compression plate just above contact (no preload) | Zwick machine |
| ☐ | Launch interface and configure data logging parameters | Zwick software |
| ☐ | Final confirmation of alignment and safety clearance | Flashlight |
| Done ? | Task | Time | Operator |
|---|---|---|---|
| ☐ | Start compression cycle to 2000 N | ~2m | TBA |
| ☐ | Hold load for minimum 10 minutes | 10m | TBA |
| ☐ | Unload and reset machine | 1m | TBA |
| ☐ | Repeat entire cycle 4–5 times | 30m | TBA |
| ☐ | Monitor part for damage or deformation | — | TBA |
| ☐ | Record force-time data and take notes | — | TBA |
| Done ? | Step | Tool |
|---|---|---|
| ☐ | Begin loading ramp until force reaches 2000 N | Zwick software |
| ☐ | Observe and maintain constant force for 10 minutes | Graph display |
| ☐ | Inspect visually for delamination, cracking, or deformation | Eyes + Camera |
| ☐ | Remove load gradually and return to zero | Zwick UI |
| ☐ | Wait 1–2 minutes, then repeat for next cycle | — |
| Done ? | Task | Time | Operator |
|---|---|---|---|
| ☐ | Remove boattail carefully from the machine | 5m | TBA |
| ☐ | Perform detailed visual inspection | 5m | TBA |
| ☐ | Photograph part, ends and compression area | 5m | TBA |
| ☐ | Export and save all test data | 5m | TBA |
| ☐ | Clean up work area and shutdown machine | 5m | TBA |
| ☐ | Upload results and document observations | 10m | TBA |
| Done ? | Step | Tool |
|---|---|---|
| ☐ | Raise top platen and remove boattail gently | Zwick UI, Gloves |
| ☐ | Inspect surfaces for cracks, indentations, delamination | Flashlight |
| ☐ | Take photos of top, bottom and contact regions | Camera |
| ☐ | Export force-time data, label with date/version | Laptop |
| ☐ | Fill test summary sheet and upload report and photos | Shared Drive |