The coupon gauge region and gripping regions serve different test functions.

Composite Tensile Coupons: Gripping and Alignment Belong in the Report

A tensile coupon test needs a controlled loading and measurement arrangement. Grip configuration, alignment and the observed failure location help explain the result. They are part of the test context, not incidental photographs to discard after the numbers are entered.

The agreed method defines the relevant specimen and test arrangement. Keep dimensions, laminate direction and any required tab information with the record. A failure near the gripping region needs evaluation under the applicable method rather than being automatically accepted as the material strength.

Retain the strain measurement basis

Instron describes composite tensile accessories that measure axial strain on both specimen sides to address bending associated with misalignment. For an enquiry, specify the required method and reporting rather than prescribing an improvised instrumentation setup. The measurement basis should remain clear in a comparison.

Connect the report to its specimen

Record the specimen identity, construction, condition and observed failure information. If a result is excluded, retain the stated reason and replacement-test history. A clean average without that context can conceal an unresolved test problem. These are laboratory reporting questions; a purchaser should confirm qualified test arrangements rather than infer validity from a video of a specimen breaking.

Retain specimen history and the basis for assessing result validity.
Retain specimen history and the basis for assessing result validity. View full size.

For the project review: specimen direction and gripping arrangement; strain measurement basis; failure location and validity review; excluded results and specimen history.

Further reading: Instron: composite test fixtures.