Research On The Thermal Performance Of Nomex Honeycomb Sandwich Structure Heated By Laser

The study of the correlation between temperature and mechanical properties of Nomex honeycomb sandwich panels can provide a reference for their engineering applications. In this paper, the thermal and mechanical properties, especially the correlation between temperature and bending properties of Nomex honeycomb sandwich structures are studied with experimental measurements in uniform heating and laser heating condition.When the temperature is high, the Nomex honeycomb sandwich structures will experience thermal decomposition. Samples are made at various thickness position of the panels, and the thermal gravimetric analysis(TGA) experiments are performed to identify their characteristic temperature for obvious thermal decomposition and the kinetic parameters for thermal decomposition.In the condition of uniform heating, the bending stiffness and the shear stiffness of Nomex honeycomb sandwich panels are measured in different temperatures with the overhanging beam three-point bending method, based on which the elasticity modulus in different directions of the panel and the shear elasticity modulus of the honeycomb core are calculated. The results show that: with the temperature increasing, the bending stiffness, shear stiffness and peak load of the Nomex honeycomb sandwich structure all decrease obviously. At a high temperature, the failure mode of panels separating from honeycomb core can be easily seen, which may result from the performance degradation of the adhesives.Based on the overhanging beam three-point bending method, the experiment system is set up in laser heating to test the change of bending properties for Nomex honeycomb sandwich panels. The change of bending and shear stiffness with time is measured in irradiation of different laser power density. Relationship between stiffness and temperature in laser heating is built. Comparing to the uniform heating, the bending stiffness and shear stiffness decrease to nearly zero when the temperature is not high in the condition of laser heating.