Fire resistance test of CFRP composite in bench scale
Source: BAM, division Technical Properties of Polymeric Materials
Fire stability is one of the biggest issues of carbon fibre reinforced polymer (CFRP) composites, particularly when they are used in load bearing applications. As soon as the glass transition temperature of the polymer matrix (100-200°C) is achieved, the composite loses its structural integrity leadings to distortion of the material and ultimately failure. Generally, the fire stability testing of components in realistic conditions requires intermediate-scale or full-scale investigations. The proposed bench-scale setup offers the possibility to simulate the key parameters for a proper assessment of fire resistance of composites during their development. This method saves time, effort, personnel, and costs.
The principal fire stability test is based on simultaneous application of fire and mechanical load. Since the carbon fibres can transfer the tensile loads quite well, the compression load is chosen as a required mechanical load for a test. The device has ability to apply mechanical load up to 232.4 kN. The fire test is preceded by a static load test at room temperature, to determine the ultimate failure load. 10% of compression failure load and the direct flame of a fully developed fire (heat flux ≈ 180 kW m-2) are applied simultaneously to the specimen, while the time to failure is measured. The flame is applied according to fire tests used in aviation, e. g. 14 CFR 25.856 Appendix F Part VII; 2003 using a NextGen burner.
This paper of the month shows that bench scale fire stability setup is a practicable and efficient method to assess protective concepts. Therefore, in cooperation with international partners, three different kinds of protective approaches were performed: nonstructured film, non-woven insulation mats and intumescent coatings. CFRP composite shell specimens were cut from quasi-isotropic, symmetrical laminate (1050 x 550 x 3 mm) composed of 24 carbon layers and covered with different protective coatings: layered silicates clay/ nanofibrillated cellulose papers (120 x 120 mm), non-woven sandwich composites (150 x 150 mm) and intumescent coatings (120 x 120 mm). The additional protection provided the thermal insulation for CFRP specimens and prolonged the time to failure significantly.
Bench-scale fire stability testing – Assessment of protective systems on carbon fibre reinforced polymer composites
Weronika Tabaka, Sebastian Timme, Tobias Lauterbach, Lilian Medina, Lars A. Berglund, Federico Carosio, Sophie Duquesne, Bernhard Schartel
published in Polymer Testing, Vol. 102, page 107340, 2021
BAM division Technical Properties of Polymeric Materials