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Steady-state traveling waves in structures have been previously investigated for a variety of purposes including propulsion of objects and agitation of a surrounding medium. In the field of additive manufacturing, powder bed fusion (PBF) is a commonly used process that uses heat to fuse regions of metallic or polymer powders within a loose bed. PBF processes require post-process removal of loose powder, which can be difficult when blind holes or complex internal geometry are present in the fabricated part. Here, a preliminary investigation of a simple part is conducted examining the use of traveling waves for post-process de-powdering of additively manufactured specimens. The generation of steady-state traveling waves in a structure is accomplished through excitation at a frequency between two adjacent resonant frequencies of the structure, resulting in two-mode excitation. This excitation can be generated by bonded piezoceramic elements actuated by a sinusoidal voltage signal. The response of the structure is affected by the parameters of the excitation, such as the particular frequency of the voltage signal, the placement of the piezoceramic actuators, and the phase difference in the signals applied to different actuators. Careful selection of these parameters allows adjustment of the quality, wavelength, and wave speed of the resulting traveling waves. In this work, open-top rectangular box specimens composed of sintered nylon powder and coated with fine sand are used to represent freshly fabricated parts yet-to-be cleaned of un-sintered powder. Steady-state traveling waves are excited in the specimens while variations in the frequency content and phase differences between actuation points of the excitation are used to affect the characteristics of the dynamic response. The effectiveness of several response types for the purpose of moving un-sintered nylon powder within the specimens is investigated.
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Utilizing Steady-State Traveling Waves in a Quiescent Water Environment for Particle Propulsion
Abstract Using steady-state traveling waves as a propulsion mechanism emerges as a highly effective strategy for displacing particles, eliminating the need for an external fluid transfer pump. This experimental inquiry delves into the intricate application of traveling waves within a beam submerged in quiescent water, deploying two distinctive force input methods to govern particle movement acoustically. The complexity of this research lies in balancing the finesse of particle motion while concurrently imposing constraints on the number of control cycles implemented. To address this challenge comprehensively, we introduce a diverse range of control cycles tailored to manipulate particles of varying sizes. Navigating the nuanced dynamics of this system requires a sophisticated approach, prompting the adoption of the Reinforcement Learning Approach. This methodological choice empowers us to discern the characteristics of traveling waves necessary for facilitating the movement of particles with divergent sizes. The utilization of Reinforcement Learning not only refines our understanding of the intricate interplay between waves and particles but also enhances our ability to optimize control strategies in this particular context. The significance of this research extends beyond the confines of the laboratory, resonating in various applications, with particular prominence in advancing transportation mechanisms for cells and analogous entities. By elucidating the underlying principles governing the interaction between traveling waves and particles of different sizes, the findings offer invaluable insights that can be harnessed to optimize particle manipulation techniques. This holds potential implications in biotechnology, where the precision control of particle movement is pivotal for applications ranging from targeted drug delivery to the manipulation of biological cells. Furthermore, our exploration not only contributes to the theoretical understanding of particle manipulation through traveling waves but also yields tangible practical implications. The versatility of our approach, as exemplified through the successful manipulation of particles with varying sizes, underscores its potential applicability across a spectrum of scenarios, emphasizing its broader relevance within the burgeoning field of acoustic fluids. In conclusion, the utilization of steady-state traveling waves as a particle propulsion mechanism, as showcased in this experimental investigation, not only holds promise for the advancement of particle manipulation but also underscores its potential impact in diverse applications. Through the thorough exploration of control cycles and the strategic application of the Reinforcement Learning Approach, this research not only contributes to the theoretical knowledge underpinning acoustofluidics but also provides practical methodologies for precision particle manipulation. These advancements are poised to play a pivotal role in shaping the future landscape of biotechnology and related fields, where fine-tuned control over particle dynamics is a cornerstone for innovation and progress.
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- Award ID(s):
- 2301776
- PAR ID:
- 10562623
- Publisher / Repository:
- American Society of Mechanical Engineers
- Date Published:
- ISBN:
- 978-0-7918-8832-2
- Format(s):
- Medium: X
- Location:
- Atlanta, Georgia, USA
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1115/SMASIS2024-140461
