Crystal Elasticity

5Experimental Macroscopic Elasticity: Relation with Structural Aspects and Physical Properties

While elasticity was until now approached from a phenomenological perspective, based on ideal monocrystals, things are quite different when actual functional materials are characterized. These may have specific structures or defects at nano- to microscopic scale. Moreover, a coupling between elasticity and certain physical properties is possible. This may sometimes provide surprises to the experimenter. Some cases having sometimes distinctive properties are approached in this chapter.

5.1. A high-performance experimental method

As already mentioned in the Introduction, experimental methods that were more physical than the conventional mechanical tests, such as the tension test (Gadaud 2008), were developed at the beginning of the 20th century. Among them is the dynamic resonant method. It derives from the widely used pulse method, which gave rise to an updated international standard (ASTM 2001). Thanks to the progress of instrumentation, the excitation and resonance detection methods were improved at the former LMPM in Poitiers in the 1990s (Mazot et al. 1992). Without getting into further details, an electrostatic measuring bridge controls a capacitor created between the sample and an electrode, which provides contactless measurement. This section only presents three types of experimental tests dedicated to the study of massive crystal materials, and further theoretical developments ...