Summary
We address in this communication the use of phase resonance testing, practically realized by phase lock loop experimental continuation of periodic solutions, to measure the conservative backbone curves of a geometrically nonlinear structure. We focus on highly flexible structures, such as cantilever elements, for which the transverse stiffness is related only to bending, without additional nonlinear stretching effects such as in plates, shells or axially restrained 1D structures. In this case, the geometrical nonlinearity is weak and noticeable only at very large amplitude. The communication will show that phase resonance testing is a way of measuring the nonlinear modes of a structure independently of damping effects and their nature (linear, nonlinear etc.), provided it is smooth. Then, by monitoring the input forcing, it is possible to estimate the damping law as a function of the amplitude of the motion.
