PSI - Issue 14

Author name / Structural Integrity Procedia 00 (2018) 000 – 000

6

S. Narendar et al. / Procedia Structural Integrity 14 (2019) 89–95

94

5. Experimental Results and Discussions

The applied non-dimensional forces (both axial and lateral) versus time are plotted and shown in Fig. 3(a). The radome was first loaded to proof load and then the thermal load was applied; and after the completion of thermal profile, the radome was loaded up to failure. It can be seen that the radome withstood the 2.5 times of the proof load till failure. The failure load is simulated only in lateral direction. The corresponding deflection data are plotted and shown in Fig 3(b). The measured deflection at the end of thermal profile application is 2.6 mm. The deflection of the radome is increased to 4.3 times of the test prediction one at the failure load. Just before the failure the radome is deflected up to 11.2 mm. Both the lateral load and the deflections are linear throughout the thermo-structural test. The present thermo-structural test qualification of ceramic radome comes under the stiffness-based design qualification.

Fig. 4. (a) Desired versus achieved temperature profiles, (b) calculated heat fluence in the test, (c) power to the infrared heating systems and (d) measured front and back wall temperatures.

Once the desired axial and lateral proof loads are achieved on the radome section, the thermal profile is simulated in a closed loop manner. During the thermal load application, the structural loads are kept constant at their proof values. After the completion of thermal load, the lateral loads are increased up to failure of the radome and during this process, the axial structural load is kept constant at its proof value. This procedure is followed to understand the structural behaviour of the ceramic radome under thermal environment. The maximum deflection measured on the ceramic radome during the thermo-structural (proof) loading is 2.6 mm. It can be seen that the