Acoustic characterization of void distributions across carbon-fiber composite layers

Rostand Tayong Boumda, Robert A. Smith, Valerie J. Pinfield

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

3 Citations (Scopus)
428 Downloads (Pure)


Carbon Fiber Reinforced Polymer (CFRP) composites are often used as aircraft structural components, mostly due to their superior mechanical properties. In order to improve the efficiency of these structures, it is important to detect and characterize any defects occurring during the manufacturing process, removing the need to mitigate the risk of defects through increased thicknesses of structure. Such defects include porosity, which is well-known to reduce the mechanical performance of composite structures, particularly the inter-laminar shear strength. Previous work by the authors has considered the determination of porosity distributions in a fiber-metal laminate structure [1]. This paper investigates the use of wave-propagation modeling to invert the ultrasonic response and characterize the void distribution within the plies of a CFRP structure. Finite Element (FE) simulations are used to simulate the ultrasonic response of a porous composite laminate to a typical transducer signal. This simulated response is then applied as input data to an inversion method to calculate the distribution of porosity across the layers. The inversion method is a multi-dimensional optimization utilizing an analytical model based on a normal-incidence plane-wave recursive method and appropriate mixture rules to estimate the acoustical properties of the structure, including the effects of plies and porosity. The effect of porosity is defined through an effective wave-number obtained from a scattering model description. Although a single-scattering approach is applied in this initial study, the limitations of the method in terms of the considered porous layer, percentage porosity and void radius are discussed in relation to single- and multiple-scattering methods. A comparison between the properties of the modeled structure and the void distribution obtained from the inversion is discussed. This work supports the general study of the use of ultrasound methods with inversion to characterize material properties and any defects occurring in composites structures in three dimensions. This research is part of a Fellowship in Manufacturing funded by the UK Engineering and Physical Sciences Research Council (EPSRC) aimed at underpinning the design of more efficient composite structures and reducing the environmental impact of travel.

Original languageEnglish
Title of host publication42nd Annual Review of Progress in Quantitative Nondestructive Evaluation
Subtitle of host publicationIncorporating the 6th European-American Workshop on Reliability of NDE: Volume 35 Edited by Leona
EditorsDale E. Chimenti, Leonard J. Bond
PublisherAmerican Institute of Physics (AIP)
Number of pages10
ISBN (Print)9780735413535
Publication statusPublished - 10 Feb 2016
Event42nd Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE 2015): Incorporating the 6th European-American Workshop on Reliability of NDE - Minneapolis, Minnesota, United States
Duration: 26 Jul 201531 Jul 2015
Conference number: 42

Publication series

NameAIP Conference Proceedings
PublisherAIP Publishing
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


Conference42nd Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE 2015)
Abbreviated titleQNDE 2015
Country/TerritoryUnited States
CityMinneapolis, Minnesota


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