title: Wave dispersion and attenuation on human femur tissue.
abstract: Cortical bone is a highly heterogeneous material at the microscale and has one of the most complex structures among materials. Application of elastic wave techniques to this material is thus very challenging. In such media the initial excitation energy goes into the formation of elastic waves of different modes. Due to "dispersion", these modes tend to separate according to the velocities of the frequency components. This work demonstrates elastic wave measurements on human femur specimens. The aim of the study is to measure parameters like wave velocity, dispersion and attenuation by using broadband acoustic emission sensors. First, four sensors were placed at small intervals on the surface of the bone to record the response after pencil lead break excitations. Next, the results were compared to measurements on a bulk steel block which does not exhibit heterogeneity at the same wave lengths. It can be concluded that the microstructure of the tissue imposes a dispersive behavior for frequencies below 1 MHz and care should be taken for interpretation of the signals. Of particular interest are waveform parameters like the duration, rise time and average frequency, since in the next stage of research the bone specimens will be fractured with concurrent monitoring of acoustic emission.
authors.affiliation: Department of Mechanics of Materials and Constructions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium. maria.strantza@vub.ac.be.
authors.forename: Maria
authors.initials: M
authors.lastname: Strantza
authors.affiliation: Department of Radiology, UZ Brussel,Vrije Universiteit Brussel, Avenue du Laerbeek 101, 1090 Brussels, Belgium. olivia.louis@uzbrussel.be.
authors.forename: Olivia
authors.initials: O
authors.lastname: Louis
authors.affiliation: Department of Mechanical Engineering and Aeronautics, University of Patras, Panepistimioupolis Rion, 26500 Patra, Greece. polyzos@mech.upatras.gr.
authors.forename: Demosthenes
authors.initials: D
authors.lastname: Polyzos
authors.affiliation: Department of Mechanics of Materials and Constructions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium. frans.boulpaep@vub.ac.be.
authors.forename: Frans
authors.initials: F
authors.lastname: Boulpaep
authors.affiliation: Department of Mechanics of Materials and Constructions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium. danny.van.hemelrijck@vub.ac.be.
authors.forename: Danny
authors.initials: D
authors.lastname: van Hemelrijck
authors.affiliation: Department of Mechanics of Materials and Constructions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium. daggelis@vub.ac.be.
authors.forename: Dimitrios G
authors.initials: DG
authors.lastname: Aggelis
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D003198:Computer Simulation; D005269:Femur / Q000502:physiology*; D006801:Humans; D013016:Sound