Frangibility Of Airport Approach Lighting Towers
Free (open access)
D G Zimcik, M Nejad Ensan & M H Farha
A series of full-scale impact tests on approach lighting towers, used at Canadian airports, was conducted to provide information on tower response. These data were necessary for the development of simplified requirements and test methods for the design of frangible structures, which will minimize the impact hazard to aircraft. A total of 48 tests were completed which included striking the tower triangular cross-section at both the apex and on the side at high, medium and low impact speeds (140, 80 and 50 km/h). High-speed video cameras were used during test program to record the impact sequence, the mode of failure and the contact time between the impactor and the tower. The influence of impact speed on the maximum impact force, energy to maximum force and energy over the contact period were key parameters measured in order to define the requirements for frangibility. A discrete model to simulate the impact of the tower was developed using finite element analysis (FEA). The results obtained from this model were compared to the full-scale test results to validate the accuracy of the model. In addition, the tower dynamic behavior was compared to the visual data obtained from the high-speed video cameras to confirm failure mode predictions.