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Full-Text Articles in Engineering

Planar Compliance Realization With Two 3-Joint Serial Mechanisms, Shuguang Huang, Joseph M. Schimmels Oct 2022

Planar Compliance Realization With Two 3-Joint Serial Mechanisms, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

In this paper, the realization of any specified planar compliance with two 3R serial elastic mechanisms is addressed. Using the concept of dual elastic mechanisms, it is shown that the realization of a compliant behavior with two serial mechanisms connected in parallel is equivalent to its realization with a 6-spring fully parallel mechanism. Since the spring axes of a 6-spring parallel mechanism indicate the geometry of a dual 3R serial mechanism, a new synthesis procedure for the realization of a stiffness matrix with a 6-spring parallel mechanism is first developed. Then, this result is extended to a geometric construction-based synthesis …


Poly (5-Carboxyindole)–Β-Cyclodextrin Composite Material For Enhanced Formaldehyde Gas Sensing, John N. Hodul, Nikhil F. Carneiro, Allison K. Murray, Wilson Lee, Kelly M. Brayton, Xinping He, Carsten Flores-Hansen, Dimitry Zemlyanov, George T.-C. Chiu, James E. Braun, Bryan W. Boudouris, Jeffrey F. Rhoads Jun 2022

Poly (5-Carboxyindole)–Β-Cyclodextrin Composite Material For Enhanced Formaldehyde Gas Sensing, John N. Hodul, Nikhil F. Carneiro, Allison K. Murray, Wilson Lee, Kelly M. Brayton, Xinping He, Carsten Flores-Hansen, Dimitry Zemlyanov, George T.-C. Chiu, James E. Braun, Bryan W. Boudouris, Jeffrey F. Rhoads

Mechanical Engineering Faculty Research and Publications

Formaldehyde, a compound commonly employed in many construction materials, paints, and plastics, has been linked to deleterious health effects. Thus, monitoring the presence of formaldehyde in interior locations is increasingly important when it comes to public health. Currently, there is a crucial need for a low-cost, small-scale, selective, and sensitive indoor sensor capable of real-time formaldehyde detection. To meet these performance metrics, materials need to be incorporated onto existing gas sensor platforms to act as chemically selective recognition layers. A main challenge when addressing this issue is creating a material that can remain easily processable, can be easily synthesized, and …


Microstructural Characteristics And Mechanical Properties Of Additively Manufactured Cu–10sn Alloys By Laser Powder Bed Fusion, Abhishek Mehta, Le Zhou, Holden Hyer, Thinh Huynh, Binghao Lu, Erica J. Drobner, Sun Hong Park, Yongho Sohn Mar 2022

Microstructural Characteristics And Mechanical Properties Of Additively Manufactured Cu–10sn Alloys By Laser Powder Bed Fusion, Abhishek Mehta, Le Zhou, Holden Hyer, Thinh Huynh, Binghao Lu, Erica J. Drobner, Sun Hong Park, Yongho Sohn

Mechanical Engineering Faculty Research and Publications

Cu – 10 wt% Sn (Cu–10Sn) alloy specimens were additively manufactured by varying the laser powder bed fusion (LBPF) processing parameters, e.g., laser power (200–350 W) and laser scan speed (100–1400 mm/s) at a fixed hatch spacing (0.12 mm) and slice thickness (0.03 mm), to examine their effects on the density, melt pool structure, and microstructure. Microstructural characteristics of the most dense sample were examined using electron microscopy (SEM, TEM) and X-ray Diffraction. The grains in the top-most melt pool layer showed a fan-like structure, whereas all other areas showed small columnar structure aligned nearly parallel to the build direction …


Elimination Of Extraordinarily High Cracking Susceptibility Of Aluminum Alloy Fabricated By Laser Powder Bed Fusion, Holden Hyer, Le Zhou, Sharon Park, Thinh Huynh, Abhishek Mehta, Saket Thapliyal, Rajiv S. Mishra, Yongho Sohn Mar 2022

Elimination Of Extraordinarily High Cracking Susceptibility Of Aluminum Alloy Fabricated By Laser Powder Bed Fusion, Holden Hyer, Le Zhou, Sharon Park, Thinh Huynh, Abhishek Mehta, Saket Thapliyal, Rajiv S. Mishra, Yongho Sohn

Mechanical Engineering Faculty Research and Publications

Using the calculation of phase diagrams approach and Scheil solidification modeling, the Al-2.5Mg-1.0Ni-0.4Sc-0.1Zr alloy was designed, intentionally with an extraordinarily high cracking susceptibility, making it prime for solidification cracking during laser powder bed fusion. This study demonstrates the ability to mitigate even the most extreme solidification cracking tendencies in aluminum alloys with only minor alloying additions of Sc and Zr, 0.5 wt.% max. Furthermore, by employing a simple direct ageing heat treatment, good tensile mechanical properties were observed with a yield strength of 308 MPa, an ultimate tensile strength of 390 MPa, and a total elongation of 11%.


A Continuum Damage Approach To Spallation And The Role Of Microinertia, S. B. Qamar, John A. Moore, Nathan R. Barton Feb 2022

A Continuum Damage Approach To Spallation And The Role Of Microinertia, S. B. Qamar, John A. Moore, Nathan R. Barton

Mechanical Engineering Faculty Research and Publications

Spall failure is of interest due to its prevalence in high strain rate problems in which the spallation is driven by the interaction of release waves. In this article, a porosity-based damage model that includes microinertial effects is used to examine spall failure. The model is successfully calibrated to plate impact-driven experiments and then used to evaluate experimental conditions producing more extreme strain rate conditions, such as those in laser-driven experiments. The incorporation of microinertia allows us to better understand the increase in apparent macroscopic spall strength seen at high strain rates. Correspondingly, we conclude that the incorporation of microinertial …


Microstructural Development In Inconel 718 Nickel-Based Superalloy Additively Manufactured By Laser Powder Bed Fusion, Thinh Huynh, Abhishek Mehta, Kevin Graydon, Jeongmin Woo, Sharon Park, Holden Hyer, Le Zhou, D. Devin Imholte, Nicolas E. Woolstenhulme, Daniel M. Wachs, Yongho Sohn Jan 2022

Microstructural Development In Inconel 718 Nickel-Based Superalloy Additively Manufactured By Laser Powder Bed Fusion, Thinh Huynh, Abhishek Mehta, Kevin Graydon, Jeongmin Woo, Sharon Park, Holden Hyer, Le Zhou, D. Devin Imholte, Nicolas E. Woolstenhulme, Daniel M. Wachs, Yongho Sohn

Mechanical Engineering Faculty Research and Publications

Excellent weldability and high temperature stability make Inconel 718 (IN718) one of the most popular alloys to be produced by additive manufacturing. In this study, we investigated the effects of laser powder bed fusion (LPBF) parameters on the microstructure and relative density of IN718. The samples were fabricated with independently varied laser power (125–350 W), laser scan speed (200–2200 mm/s), and laser scan rotation (0°–90°). Archimedes’ method, optical microscopy, and scanning electron microscopy were employed to assess the influence of LPBF parameters on the relative density and microstructure. Optimal processing windows were identified for a wide range of processing parameters, …


The Relationship Between Mechanism Geometry And The Centers Of Stiffness And Compliance, Shuguang Huang, Joseph M. Schimmels Jan 2022

The Relationship Between Mechanism Geometry And The Centers Of Stiffness And Compliance, Shuguang Huang, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

A significant amount of research has been directed toward developing a more intuitive appreciation of spatial elastic behavior. Results of these analyses have often been described in terms of the elastic behavior (stiffness or compliance) centers. This paper investigates the properties of centers of stiffness and compliance and provides a fresh view of elastic center locations, specifically, the locus of centers associated with a given mechanism’s topology and geometry. We show that the location of the center of stiffness (compliance) for a set of elastic components connected in parallel (in serial) can be described in terms similar to the …