Michael A. Klecka

Design and topology/shape structural optimisation for additively manufactured cold sprayed components

Integrating advanced structural optimisation, such as topology optimisation (TO), with additive manufacturing (AM) allows design and fabrication of extremely efficient and effective components. Such integration is challenging because characteristics can vary from process to process. In this paper, designing and optimising a part for the cold spray AM process is demonstrated. Cold spray process characteristics and constraints are enforced throughout. The analysis shows a tradeoff between stress and mass, but the combined process delivers a structure at much lower stress (up to 3X reduction in peak stress in a case study) with the capability to be much lighter than the original part (case study: 20% reduction in weight). The general approach to specifying design guidelines, interpreting TO results, and applying other structural optimisation methods is directly applicable to many AM processes – and especially other spray deposition techniques – in addition to cold spray.

Real Time NDE of Cold Spray Processing Using Acoustic Emission

As interest continues to grow in Additive Manufacturing (AM) processes, the inspection challenges that arise in this class of material need to be addressed. This must be balanced by considering cost and finding defects as soon as feasible in the process to minimize downstream production impacts. As a means to consider defect detection as early as possible, acoustic emission (AE) was used to monitor the cold spray powder deposition process. The concept was to observe the article being coated for the acoustic signature of internal cracking or interface delamination, resulting in a quick and cost-effective means to detect problems during cold spray parameter development and ultimately during production. Real time monitoring was used to delineate between particle impacts and more significant events such as delamination and internal cracking. The results of this study show that AE can be used to monitor processes in extremely noisy environments. Opportunities for extension to other additive manufacturing processes will be discussed.

A Multi-Scale, Multi-Physics Optimization Framework for Additively Manufactured Structural Components

This paper proposes an optimization framework enabling the integration of multi-scale / multi-physics simulation codes to perform structural optimization design for additively manufactured components. Cold spray was selected as the additive manufacturing (AM) process and its constraints were identified and included in the optimization scheme. The developed framework first utilizes topology optimization to maximize stiffness for conceptual design. The subsequent step applies shape optimization to refine the design for stress-life fatigue. The component weight was reduced by 20% while stresses were reduced by 75% and the rigidity was improved by 37%. The framework and analysis codes were implemented using Altair software as well as an in-house loading code. The optimized design was subsequently produced by the cold spray process.