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Computational and Experimental Investigation of Inert Gas Flow Field in Direct Metal Laser Melting Printer Build Chambe

Czekałowski Paweł, Stryczniewicz Wit, Żuk Paweł, Panna Krzysztof, Borkowski Paweł, Bujak Michał, Iglewski Tomasz

Advances in Science and Technology. Research Journal

2023

Vol. 17, no 6

378--387

Additive manufacturing methods are becoming more and more popular in today’s production market. These methods became a useful and flexible alternative to traditional manufacturing approach. One of the most popular methods in this family is Direct Metal Laser Melting. It can achieve high quality prints, however, numerous parameters need to be established, to achieve a good quality product. One of the aspects of printing process is inert gas flow. The goal of presented study is to quantitatively assess inert gas flow field using both experimental and numerical methods. Flow field parameters have been measured with anemometry and Particle Image Velocimetry. Additionally Computational Fluid Dynamics tools were used to investigate flow phenomena occurring inside the build chamber. PIV measurements give good insight into the flow field, but they are costly and require significant time for preparation. For this reason, CFD analysis is widely used as a design tool, giving reasonable turnaround time. In addition, every design tool to be reliable need to be validated against test data. In this study the team was able to collect both experimental and numerical data and finally conduct the validation. Work allowed to determine the most suitable approach for predictions in given problem. Different turbulence models have been tested. Simulation results were validated against collected experimental data.

Bone conduction stimulation of the otic capsule: a finite element model of the temporal bone

Borkowski Paweł, Marek Piotr, Niemczyk Kazimierz, Lachowska Magdalena, Kwacz Monika, Wysocki Jarosław

Acta of Bioengineering and Biomechanics

2019

Vol. 21, no. 3

75--86

Bone conduction stimulation applied on the otic capsule may be used in a conductive hearing loss treatment as an alternative to the bone conduction implants in clinical practice. A finite element study was used to evaluate the force amplitude and direction needed for the stimulation. Methods: A finite element model of a female temporal bone with a precisely reconstructed cochlea was subjected to a harmonic analysis assuming two types of stimulation. At first, the displacement amplitude in the form of air conduction stimulation was applied on the stapes footplate. Then the force amplitude was applied on the otic capsule in the form of bone conduction stimulation. The two force directions were considered: 1) the primary direction, when a typical opening is performed during mastoidectomy, and was coincident with the axis of an imaginary cone, inscribed in the opening, and 2) the direction perpendicular to the stapes footplate. The force amplitude was set so that the response from the cochlea corresponded to the result of air conduction stimulation applied on the stapes footplate. Results: The amplitude and phase of vibration and the volume displacement on the round window membrane were considered as well as vibrations of the basilar membrane, spiral lamina, and promontory. Conclusions: The cochlear response was comparable for the two types of stimulation. The efficiency of bone conduction stimulation depended on the force direction. For the primary direction, the force was a few times smaller than for the direction perpendicular to the stapes footplate.