<p>Although automatic impact hammers are being used in dynamics and vibration research, they have seen little application in resource-poor settings, such as undergraduate labs and the parts of the developing world. The primary reason for the limited spread of such a technology is their cost, as a commercially available automatic modal hammer typically costs more than USD 10000. An inexpensive, easy to assemble automatic modal hammer can thus be helpful in educational labs and promote the "Do it yourself" attitude in future scientists. This research describes a new approach to making a low-cost, repeatable, and scalable automatic modal hammer. The primary focus of the study is on creating and using an open-source, scalable, repeatable, low-cost automatic modal hammer for investigating the dynamics of strongly nonlinear systems. The design consists of a standard modal hammer mounted on a stepper motor's shaft with an encoder controlled using a hybrid servo drive and a microcontroller. The motor, servo drive, and encoder combination allow for micro-stepping and precise control of the motor shaft and, thus, the modal hammer's motion. The stepper motors used in this hammer are the ones that are used in small 3D printers and CNC machines and therefore are widely available at a low cost. The functionality of the automatic hammer is demonstrated using a model airplane wing with a non-smooth nonlinear vibration absorber.</p>

An Open-Source, Low-Cost Automatic Modal Hammer  for Studying Nonlinear Dynamical Systems

Paper Proceedings: https://asmedigitalcollection.asme.org/IDETC-CIE/IDETC-CIE2021/volume/85369

ASME 2021 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference (IDETC/CIE2021)

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