Nondestructive evaluation methods for damage assessment in fiber‐metal laminates

Abstract

Aerospace Research (IAR) is engaged in a collaborative project with Bombardier Aerospace. The main objective of the project is to evaluate the potential of applNg fiber-metal laminates (FML) to aircraft types manufactured by Bombardier. As a part of this project, nondestructive evaluation (NDE) procedures have been developed and used at IAR to determine the extent of damage caused by impact, corrosion and fatigue loads in a commercial FML material (GLARE). X-rays using radioopaque fluids as well as conventional and air-coupled ultrasonic and eddy current methods have been investigated. This report describes the NDE procedures employed at IAR to assess damage in FML and provides examples of the results obtained utilizing each of the inspection methods and the damage types investigated. Also, the ability of the investigated NDE methods to determine damage size and the accuracy of damage measurements is discussed.

The mechanical behavior of GLARE laminates for aircraft structures

“…Moreover, the internal impact damage is formed in composite laminates extending well beyond the impacted area, which significantly reduces the strength and stiffness of composite structures. However, research [59][60][61][62] has indicated that GLARE is not susceptible to the formation of large areas of internal damage under impact loading. The internal impact damage in GLARE is mostly confi ned to a relatively small area surrounding the point of impact.…”

Effects of interface stiffness and delamination on resonant oscillations of metal laminates

“…In non-destructive testing of the interface of the metal laminate, ultrasonic speculation method and the transmittance X-ray inspection have been often applied [3,4]; however, an easier and quicker method would be preferable for practical evaluations.…”

Non-destructive testing investigation of gaps in thin Glare laminates

“…Various inspection methods have proven their effectiveness in the detection of different defects and damages in Glare structures. The most consolidated are based on ultrasonic C-scan inspections [9,[14][15][16][17][18]. Ultrasonic inspections are based on differences in sonic transmission of different materials and reflection on interfaces in laminates.…”

“…Among other well-known NDT techniques used in Glare it is worth mentioning ultrasonic Lamb wave propagation [21,22], eddy current testing [13,16], x-ray radiography [16], thermography [23], and shearography [24]. In addition to the different constraints inherited in each single methodology, the common drawback is related to the limitation during in-service operations.…”