Remote inline monitoring of thermal effects coupled with bending stresses of glass fibres composites

Thanks to its remote operation through thermal radiation sensing, infrared thermography has proved suitability for inline monitoring of thermal effects coupled with mechanical stresses. The attention of this work is focused on the contribution of infrared thermography in the characterization of glass fibres-based composites undergoing either very rapid, or very slow, bending under mechanical tests. Several specimens with glass fibres embedded in either a thermoset or a thermoplastic matrix are prepared and are subjected to both impact and quasi-static bending, tests. An infrared camera views the specimen surface when it is under load and records sequences of images at a proper frame rate. The acquired sequences are later post-processed and analysed. For both types of test, infrared thermography allows getting information about damage initiation and propagation and in particular about the impactor peak force and contact duration. These pieces of information, which are attained in a remote way, so without any contact with the part under investigation and without any interference with the test execution, could contribute to increase knowledge of the undergoing phenomena. The presented results are also analysed with a critical view on the selection of the infrared camera to be used for the specific test both in terms of detector resolution and frame rate.