THE INFLUENCE OF FIBREGLASSES THICKNESS ON HEAT RELEASE CHARACTERISTICS AT BURNING

All the materials intended for manufacturing of aviation technics, should correspond to requirements of aviation rules, including the fire safety. As characteristics of fire danger depend on sample thickness, therefore the analytical dependences of change of the defined fire characteristic with growth of thickness of a material is desirable. In this work are carried out researches of influence of fiberglass sample thickness on characteristics of heat released at burning (the maximal heat release rate, total heat release at 1; 2 or 5 minutes). Tests of samples of fibreglasses with thickness from 0,2 up to 4,5 mm have been implemented for polymeric binders the various chemical nature: thermoplastic with low coke formation (polycarbonate), thermoplastic with an middle coke formation (polysulphone), thermosetting plastic with high cokes number (phenolic binder). For exception of influence of filler type, all experiments are executed on the same type of fiber glass fabric — Ò-15(P)-76. Tests on heat release rate were carried out on OSU-type calorimeter according to requirements of aviation norms (heat flux 35 kW
m2 ). It is shown, that heat released lines have extreme character with a maximum at thickness 1…3 mm. For the analytical description of dependence of characteristics of a thermal emission from thickness the analytical equation of a kind y = (Ax – C) e–Bx + C is offered. Factors of the equation depend from both as a kind of the characteristic of a heat release, and nature polymeric matrix. Factors of the equations for three types of a polymeric matrix — polysulphone, polycarbonate, phenolic binder are calculated. It is shown, that the offered analytical equation allows describing experimental results on the maximal intensity of a heat release rate (peak) and total heat releases at first two minutes with satisfactory accuracy.