Session: 02-03-01: Studies in Aerospace Structural Dynamics

Paper Number: 110939

110939 - Experimental Comparative Studies on the Dynamical Responses of Additively Manufactured Cantilever Beams 

Abstract:

As technology begins to advance, it generates a web leading to the creation of new and innovative ideas. One of these ideas is Additive Manufacturing (AM). Both commercial industry and hobbyist alike are starting to throw out their old means of subtractive manufacturing and adopting AM due to the unique benefits that it presents to the user. In order to utilize AM, one must design a part through various software then upload it to the printer. This allows on the fly design changes to be made with ease while still having the capability to make very complex parts. In turn, AM made humans and material properties the limiting factor in the manufacturing process while reducing material waste and saving energy compared to subtractive manufacturing. Although this is such a revolutionary idea due to possible non-isotropic responses, little time has been devoted to investigating the dynamic properties of AM parts. Additionally, the studies that do exist show identical AM parts are exhibiting slightly different behaviors. Using two experimental setups, we examine and compare the dynamical responses of identically printed beams. To conduct both experiments, a tri-axial accelerometer is placed at the tip of the additively-manufactured beam in order to collect the experimental data. Inherently, this accelerometer can be used as a tip mass. For the first experimental setup, the beam is placed horizontally to mitigate the effects of static displacement. For the second setup, the beam is placed vertically allowing for a significant static displacement to be present in the system. Manufacturing of these beams is done using Polylactic Acid (PLA) on a Creality CR10S Pro V2 3D printer. To ensure consistency, the same build plate temperature, nozzle temperature, filament orientation, and material deposition speed are considered for each experiment. Each of the three identical beams using the same printing parameters mentioned above are utilized for both experimental setups. To determine the dynamical responses of these additively-manufactured beams, three different modes of excitation are examined, namely, free, random, and harmonic. By using free vibration and the logarithmic decrement, the variations of the dominant frequency of oscillation and damping as function of time are determined. Next by using random vibration testing, multiple modes of vibration are activated in a predetermined band. Performing an up and down sweep while using harmonic excitation capture the beam's resonant responses to different excitation frequencies. This investigation allows us to identify the presence of nonlinear softening and damping in the system’s response and the influence of the experimental setup on the dynamical properties of these additively-manufactured systems. Additionally, the possible existence of multi-stable solutions is investigated for both setups.

Key words: experimental testing, nonlinear dynamics, additive manufacturing, multi-stable solutions

 

Presenting Author: Nicholas Hall New Mexico State University

Presenting Author Biography: Nicholas joined the structural dynamics research group at New Mexico State University last year and has worked collaboratively with his colleagues to perform research of his own. Currently he is a senior who has excelled throughout his undergrad and is planning to pursue graduate studies where he can continue his research. Nicholas is working under the guidance of Los Alamos National labs and is planning to do a summer internship with Devon Energy.

Authors:

Nicholas Hall New Mexico State University
Micah Guajardo New Mexico State University
Mason Curtin New Mexico State University
Luis Corral New Mexico State University
Megan Trujillo New Mexico State University
Abdessattar Abdelkefi New Mexico State University