Optical Crack Tracer System for Automatic Fracture Toughness Measurement by Optical Monitoring of Crack Propagation La Vi s i a N Fraunhofer Polymeric Materials and Composites

Optical Crack Tracer Application LaVision Optical Crack Tracer (OCT) is a new generation of instruments for crack analysis. The OCT works on a wide range of different materials: ► Brittle and Toughened Resins ► Thermoplastic Polymers ► Adhesives, Components, Molding Resins ► Metals, Ceramics, Inorganic Glasses In combination with every standard Materials Testing Machine LaVision OCT tracks the crack optically during crack initiation and propagation and computes fully automatically the ► Critical Stress Intensity Factor Klc ► Strain Energy Release Rate Glc Fully Integrated Package In this fully...

This example shows an almost constant Klc, that indicates the true material fracture toughness has been correctly determined by this test. Obviously, an ideal pre-crack has been formed, because fracture toughness is the same for crack initiation and propagation. ► l\lo additional sample preparation ► Automatic determination of Klc and Glc ► No subsequent manual analysis of the broken specimen required ► High accuracy, needs very few samples ► High reliability (for transparent and non-transparent samples) ► Complete measurement results (calculations, graphs, printouts) within a minute ► Easy to...

Specification Optical Crack Tracer CCD-camera: 768 x 576 pixel Time resolution: 10 Hz Resolution: typically 0.05 mm (observation window 25 mm) Error of crack length: < 0.1 mm Max. time of monitoring: ca. 2 min (depending of RAM in PC and image size) Advanced PC AD-converter TTL-I/O Framegrabber Stroboscope/lightning synchronisation Software: Win-NT DaVis-6 crack software package Interface to the material testing machine (analog force signal) Optional high-speed crack recording (100 Hz, 1kHz, 40 kHz) high-resolution CCD-cameras up to 2k x 2k pixel micro-crack detection with pm-resolution Optical...