Choose the question and representative sample
State whether the test evaluates installation handling, a moving span, a material comparison, or a complete assembly. Use the motion definition to identify the relevant path and environment. Document sample count and selection with the responsible reliability owner. A coupon may isolate a variable, while a product assembly includes interactions the coupon omits.
Bend test specification
| Planning item | Question | Required record |
|---|---|---|
| Purpose | Which design decision will the result resolve? | Objective and acceptance basis |
| Sample | Does it match the intended construction? | Materials, revision and identification |
| Motion | What constrains the shape throughout travel? | Fixture drawing and programmed sequence |
| Failure detection | What event ends or fails the test? | Monitoring method and event log |
Specify fixture and monitoring
Record clamping, free length, radius convention where meaningful, trajectory, travel, rate, dwell, and nearby contact surfaces. Define electrical monitoring and the detectable event duration or measurement behavior required by the application. Coordinate connectivity criteria with the test equipment. Include stop conditions and the way interrupted tests are recorded.
Preserve evidence through completion or failure
Inspect and document samples before testing. Record exposure, observations, electrical events, and the final condition. Retain failed locations without unnecessary manipulation and compare them with the expected deformation region. A test report should distinguish completed exposure, first detected event, and later damage. Do not extrapolate a universal lifetime from one fixture or an unrepresentative hand-folding demonstration.
Before you release the design
- Freeze the fixture and sample construction for a comparison.
- Define relevant electrical and physical failure criteria in advance.
- Record any setup change, stoppage, or restraint movement.
- Retain failed and unfailed samples with their individual histories.
Watch points
- A cycle count without the motion and detection method is incomplete evidence.
- The absence of a visible crack does not establish uninterrupted electrical performance.
Practical questions
Must a test run until a sample breaks?
Not necessarily. Define the required exposure and acceptance objective. A qualification exposure, comparative experiment, and failure-analysis study can have different stopping rules.
Can accelerated cycling prove real service life directly?
Only with a justified relationship between the accelerated conditions and the real failure mechanisms. Increasing speed or changing geometry can introduce a different problem.
Technical references
References support the material or design context. Check the exact grade, part number, document revision and project conditions before release.Updated 27 September 2026 · Technical content policy · Engineering guidance supports project review; the agreed drawing defines the build.