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Alexander Dunbar

Alexander Dunbar

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9
Publications
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398
Citations

Publications

Publications (9)
Article
Simulations of offshore floating wind turbine platform dynamics typically utilize engineering tools that include simplified modeling assumptions. In this study, an open-source CFD/6-DOF solver is developed using OpenFOAM for high-fidelity simulation of offshore floating wind turbine platforms. The solver tightly couples the fluid and 6-DOF equation...
Article
Measurements of the temperature and distortion evolution during laser powder bed fusion (LPBF) are taken as a function of time. In situ measurements have proven vital to the development and validation of FE models for LPBF. Due to powder obscuring all but the top layer of the part in LPBF, many non-contact measurement techniques used for in situ me...
Article
Developing methods which allow real-time monitoring of powder bed fusion (PBF) additive manufacturing (AM) processes is key to enabling in situ assessments of build quality (e.g. lack of fusion and porosity). Here, we investigate the use of optical emission spectroscopy and high-speed (100 kHz) measurement of select wavelength emissions, based on a...
Article
A key challenge in metal additive manufacturing is the prevalence of defects, such as discontinuities within the part (e.g., porosity). The objective of this work is to monitor porosity in laser powder bed fusion (L-PBF) additive manufacturing of nickel alloy 718 (popularly called Inconel 718) test parts using in-process optical emission spectrosco...
Conference Paper
Industrial application of PBFAM continues to expand, and there is growing interest in use of sensors to monitor the process. Sensor data collected during the build provides insight into process physics, and may also lead to a reduction in overall fabrication time and cost by offering an alternative to extensive post-build nondestructive inspection...
Article
In situ experimental measurements of the laser powder bed fusion build process are completed with the goal gaining insight into the evolution of distortion in the powder bed fusion build process. Utilizing a novel enclosed instrumented system, five experimental builds are performed. Experimental builds compare materials: Ti-6Al-4V and Inconel® 718,...
Article
Support structures are required in powder bed fusion (PBF) additive manufacturing of metallic components with overhanging structures in order to reinforce and anchor the part, preventing warping during fabrication. In this study, we fabricated and tested the tensile structural strength of support structures with four different 2-dimensional lattice...
Article
Experimental measurements are a critical component of model development, as they are needed to validate the accuracy of the model predictions. Currently, there is a deficiency in the availability of experimental data for laser powder bed fusion made parts. Here, two experimental builds of cylindrical geometry, one using a rotating scan pattern and...

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Projects

Project (1)
Archived project
In the context of quality assurance in AM, the goal of this work is the identification and isolation of defects in a specific metal additive manufacturing process, called laser powder bed fusion (L-PBF) using data from in-process sensors.