Ultrasonic testing of thin walled components made of aluminum based laminates

Abstract

The goal of this paper is to evaluate the feasibility of testing thin walled components made of aluminum based laminates using ultrasonic waves. Aluminum alloys are applied in aviation, maritime and railway industries. The advantages of aluminum alloys include high specific strength, good machinability, and formability. In recent years, the position of aluminum as preferred material in transportation has been challenged by composites. The share of composites in the structure of aircraft such as AirBus A350XWB and Boeing 787 Dreamliner exceeds 50%. The application of composites allow weight to be reduced by 10 ÷ 20%. In response to the proliferation of composite structures aluminum industry started developing the next generation of aluminum lithium alloys allowing a reduction in aircraft structure weight by 8 ÷ 15%. In Bombardier CSeries aircraft the fuselage was made of aluminum lithium alloy, while the wings were made of composites. In the near future, both aluminum and composites will be used in aviation. There is a need for the development of technology for testing of thin walled components made of aluminum based sheets. In this work, ultrasonic testing of the aluminum based laminate having section thickness of 1.5 mm is presented. The laminate comprised two aluminum sheets with and without the polyimide interlayer which were joined using friction stir welding technology. The suggested ultrasonic method allowed material discontinuities having a width greater than 0.4 mm to be detected.