Biomedical Engineering Reference
In-Depth Information
15
The Use of Vibration Principles to Characterize
the Mechanical Properties of Biomaterials
Osvaldo H. Campanella
1
, Hartono Sumali
2
,
Behic Mert
3
and Bhavesh Patel
1
1
Agricultural and Biological Engineering Department and
Whistler Carbohydrate Research Center, Purdue University, West Lafayette, IN
2
Sandia National Laboratories, Albuquerque, NM
3
Department of Food Engineering, Middle East Technical University, Ankara
1,2
USA
3
Turkey
1. Introduction
Mechanical properties are a primary quality factor in many materials ranging from liquids
to solids including foods, cosmetics, certain pharmaceuticals, paints, inks, polymer
solutions, to name a few. The mechanical properties of these products are important because
they could be related to either a quality attribute or a functional requirement. Thus, there is
always a need for the development of testing methods capable to meet various material
characterization requirements from both the industry and basic research.
There is a wide range of mechanical tests in the market with a wide price range. However,
there is an increasing interest in finding new methods for mechanical characterization of
materials specifically capable to be adapted to in-line instruments. Acoustic/vibration
methods have gained considerable attention and several instruments designed and built in
government labs (e.g. Pacific Northwest National Laboratory and Argon National
Laboratory) have been made commercially available.
To measure mechanical properties of material a number of conventional techniques are
available, which in some cases may alter or change the sample during testing (destructive
testing). In other tests the strains/deformations applied are so small that the test can be
considered non-destructive. Both types of test are based on the application of a controlled
strain and the measurement of the resulting stress, or viceversa. Different types of
deformations, e.g. compression, shear, torsion are used to test these materials.
Depending on the type of material, different conventional techniques utilized to measure its
mechanical properties can be grouped as viscosity measurement tests (liquid properties),
viscoelasticity measurement tests (semiliquid/semisolid properties), and elastic
measurement tests (solid properties).
Acoustics based techniques can be used for all types of material and the following sections
discuss in detail how these techniques have been adapted and used to measure materials
whose properties range from liquids to solids. Some of the applications discussed in this
chapter are based on the basic impedance tube technique. Applications of this technique for
