High-Velocity Impact Studies on Scaled Leading Edges of Horizontal Tail with Smart Composite Layers

Rangaiah Basavanna,Karisiddappa &Nbsp,Samikkannu Raja,Jeevarathinam Dhayanidhi

doi:10.4236/aast.2022.71003

Abstract

Bird strike studies on typical aluminium leading edges of the Horizontal Tail (HT) with and without Glass Fibre Shape Memory Polymer (GF-SMP) layers are carried out. A one-fifth scaled model of HT is designed and fabricated. The parameters like bird dimension and energy requirements are accordingly scaled to conduct the bird strike tests. Two leading-edge components have been prepared, namely one with AL 2024-T3 aluminium alloy and the other specimen of the same dimension and material, additionally having GF-SMP composite layers inside the metallic leading edge, in order to enhance its impact resistance. Bird strike experiments are performed on both the specimens, impacting at the centre of the leading edge in the nose tip region with an impact velocity of 115 m/s. The test component is instrumented with linear post-yield strain gauges on the top side and the PZT sensors on the bottom. Furthermore, the impact scenario is monitored using a high-speed camera at 7000 fps. The bird strike event is simulated by an equation of state model, in which the mass of the bird is idealized using smooth particle hydrodynamics element in PAMCRASH? explicit solver. The strain magnitude and its pattern including time duration are found to be in a good correlation between test and simulation. Key metrics are evaluated to devise an SHM scheme for the load and impact event monitoring using strain gauges and PZT sensors. GF-SMP layers have improved the impact resistance of the aluminium leading edge which is certainly encouraging towards finding a novel solution for the high-velocity impact.

Highlights

The aircraft flight may face the risk of colliding with foreign objects during its life cycle
The Leading Edge (LE) was instrumented with strain gauges and Piezoelectric Sensor (PZT) sensors (See Figure 1(a)), to capture the dynamic event using high speed Data Acquisition Systems (DAS) (NI system®) at high sampling frequency 1 MHz and the event was captured by high speed cameras of 3D DIC system (Figure 1(b))
The aluminium LE feature level specimens with and without Glass Fibre Shape Memory Polymer (GF-Shape Memory Polymer (SMP)) layers were impacted at a velocity 115 m/s using a scaled gelatine mass, which is equivalent to an 8-lb bird

Summary

Introduction

The aircraft flight may face the risk of colliding with foreign objects during its life cycle. Birds are one of such foreign objects; when birds collide with the aircraft structure, the damage may turn out to be catastrophic and this collision is defined as “Bird Strike”. The onset of such collision may cause serious structural damage at the impact location of the aircraft. Extensive tests and simulations have to be conducted to make the structure more resilient towards the bird strike. The airworthiness certification authorities, namely FAA and EASA have defined the bird Strike regulations for large civil aircrafts. The certification clauses demand that the aircraft be able to successfully land after the collision with a bird at an impact velocity, which is decided based on the cruise velocity of the aircraft

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