A symmetrically piecewise linear oscillator: design and measurement

A simple piecewise linear system with symmetrical flexible constraints was designed and manufactured to carry out a wide range of experimental dynamic analysis and ultimately to validate piecewise models. The design choice wa s based on the following criteria: accuracy in representing the mathematica l model, manufacturing simplicity, flexibility in terms of parameter change s and cost effectiveness. The system consists of a block mass attached to t wo leaf springs, the stiffness of which can easily be varied by changing th eir length. The secondary stiffness in the form of cantilever beams can be widely varied in the same way. The clearance between the mass and secondary springs can also be varied by adjusting the screws at the ends of the beam s. A variable pneumatic damper is mounted on the upper surface of the mass and provides a means of changing the viscous damping coefficient. The exper imental set-up, calibration procedures and typical results are discussed.