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787 results on '"Simpson, Timothy W."'

2. An image-based transfer learning approach for using in situ processing data to predict laser powder bed fusion additively manufactured Ti-6Al-4V mechanical properties

Author

Luo, Qixiang, Shimanek, John D., Simpson, Timothy W., and Beese, Allison M.

Subjects
Physics - Applied Physics
Abstract

The mitigation of material defects from additive manufacturing (AM) processes is critical to reliability in their fabricated parts and is enabled by modeling the complex relations between available build monitoring signals and final mechanical performance. To this end, the present study investigates a machine learning approach for predicting mechanical properties for Ti-6Al-4V fabricated through laser powder bed fusion (PBF-LB) AM using in situ photodiode processing signals. Samples were fabricated under different processing parameters, varying laser powers and scan speeds for the purpose of probing a wide range of microstructure and property variations. Photodiode data were collected during fabrication, later to be arranged in image format and extracted to information-dense vectors by the transferal of deep convolutional neural network (DCNN) structures and weights pre-trained on a large computer vision benchmark image database. The extracted features were then used to train and test a newly designed regression model for mechanical properties. Average cross-validation accuracies were found to be 98.7% (r2 value of 0.89) for the prediction of ultimate tensile strength, which ranged from 900 to 1150 MPa in the samples studied, and 93.1% (r2 value of 0.96) for the prediction of elongation to fracture, which ranged from 0 to 17%. Thus, with high accuracy and hardware accelerated inference speeds, we demonstrate that a transfer learning framework can be used to predict strength and ductility of metal AM components based on processing signals in PBF-LB, illustrating a potential route toward real-time closed-loop control and process optimization of PBF-LB in industrial applications.

Published
2024
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21. An Exploration of the Effectiveness of Product Archeology in an Undergraduate Engineering Curriculum: What Can a Five-Hour Curriculum Do?

Author

Okudan Kremer, Gül E., Simpson, Timothy W., and Ashour, Omar M.

Abstract

In this paper, we present our efforts in embedding product archeology inspired curricula into two engineering courses along with assessment results. The assessment focuses on the effectiveness of the embedded curricula in enhancing students' understanding on the global, societal, environmental, and economic (GSEE) implications of engineering design. The results show the significant positive impact of the curricula as perceived by students in comparison to other engineering courses, and thus, is another testament to the fact that carefully crafted curricula can have substantial impact.

Published
2013

22. A Study on Situated Cognition: Product Dissection's Effect on Redesign Activities

Author

Grantham, Katie, Okudan Kremer, Gül E., Simpson, Timothy W., and Ashour, Omar

Abstract

Situated cognition theory describes the context of a learning activity's effect on learner's cognition. In this paper, we use situated cognition theory to examine the effect of product dissection on product redesign activities. Two specific research questions are addressed: 1) Does situated cognition, in the form of product dissection, improve product functionality during redesign exercise?, and 2) Does situated cognition, again in the form of product dissection, affect the creativity during product redesign? In this study, three sections of first-year students in two different locations--The Pennsylvania State University (Penn State) and Missouri University of Science and Technology (S&T)--performed product redesign using coffee makers. The redesigned products have been analyzed with respect to both depth (detail level) and creativity. Based on our results, we find that situated cognition, in the form of product dissection, improves product functionality during redesign and positively affects creativity. The implications of these results are also discussed.

Published
2013

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