CompositesWorld
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15 CompositesWorld.com Video Extensometry More repeatable, reliable, applicable In this demonstration, video-derived measurements were shown to give more repeatable results than a conventional KGR extensometer, while still following the rules outlined in the ASTM D 5656 standard. Potentially, this could allow for smaller specimen batches, leading to time and cost savings. Subsequent testing demonstrated that even greater consistency could be achieved by using the UVX multi-point capabilities to track strain at multiple points along the bond line. Multiple measurements also can even out the variations in stiffness seen along the bond line, further improving repeatability. A noncontact extensometry solution offers other benefits, such as removing the potential for device slippage on the specimen or ABOUT THE AUTHOR Simon Jenkins is a chartered mechanical engineer, providing technical leadership and project management in manufacturing research to GKN Aerospace (Filton, UK). Previously an applications engineer for Imetrum (Flax Bourton, UK), he supported customers by performing dynamic measurements on test articles, ranging from sub-millimeter laboratory-scale coupons to bridges in service. Before coming to Imetrum, Jenkins spent 12 years at BAE Systems (Bristol, UK) working in materials research, with specialties in nonstandard mechanical testing, high-strain-rate testing and digital image correlation. He holds a Ph.D in mechanical engineering from Bristol University. device damage at failure. Furthermore, although the KGR exten- someter was developed specifically for the ASTM D 5656 test, video metrology-equipped extensometers are more test-method agnostic. e UVX configuration used here can be employed to make measurements on other specimens and for other test method standards. UVX Flexi video extensometers, for example, are highly configurable with a wide choice of user-interchange- able camera and lens options, enabling a single system camera to be used for almost all material testing requirements. e UVX is designed for ease of use and fast throughput speeds and is ideal for batch testing. FIG. 5 The various relationships between 18 points on the critical central section of the test specimen (depicted here) can be tracked via video metrology both in real-time during the test or analyzed later in post process. Source | Imetrum 8 1 2 5 6 3 4 7 9 10 11 12 15 16 13 14 17 18 INTERNATIONAL INC. EUROPE Sarl ASIA LTD ADVANCED MATERIALS LTD PRODUCT SPOTLIGHT Filmcote ® 1524 Engineered film developed as a replacement for release liquids on the surface of mold tools Video available online Benefits: • No contamination of parts by release agents transfer. • Excellent release reduces rework or cleaning of tooling. • Film protects parts during trim and drill operation.