Effect of thermal cycling heated Fibre Metal Laminates under static load

Abstract

Heated GLARE, a Fibre Metal Laminate with an integrated heater element, has been developed for de- or anti-icing systems in aircraft structures. Besides cyclic thermal loading these structures are also subjected to mechanical loading. To investigate the effect of static loading in addition to thermal cycling a series of tests have been performed on heated GLARE using a specifically designed mechanical load fixture and thermal cycling setup. Three different tensile stress levels, 150, 200 and 300 MPa, were used in combination with up to 36,000 thermal cycles between −20 and 50 °C. The effect of the combined thermo-mechanical loading was investigated by testing the interlaminar shear properties of each sample after thermal cycling. Thermal cycling under a 150 MPa static load showed much less reduction or even increase in strength compared to previously reported test results for thermal cycling only. This effect was not found for thermal cycling under the 200 and 300 MPa static load cases. On the contrary, in these cases more reduction in strength was found compared to test results after thermal cycling without static load.