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Search Publications by: Brian Simonds (Fed)

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Displaying 1 - 25 of 48

Accurate keyhole instability prediction in metal additive manufacturing through machine learning-aided numerical simulation

February 20, 2025
Author(s)
Jiahui Zhang, Runbo Jiang, Kangming Li, Pengyu Chen, Xiao Shang, Zhiying Liu, Brian Simonds, Qianglong Wei, Hongze Wang, Jason Hattrick-Simpers, Tao Sun, Anthony Rollet, Yu Zou
A primary obstacle impeding the use of metal additive manufacturing technologies in fatigue-sensitive applications is the presence of porosity, primarily caused by keyhole instability. To tackle this challenge, it is imperative to accurately forecast

Direct Realization of the Optical Watt from Planck's Constant

October 28, 2024
Author(s)
Brian Simonds, Kyle Rogers, Sven Schulze, David Newell, Gordon Shaw, Paul A. Williams
A primary force standard is implemented to directly realize Planck's constant to the optical Watt by means of radiation pressure at the kilowatt level. The high amplification laser-pressure optic, or HALO, is a multiple reflection radiation pressure

Benchmark Study of Melt Pool and Keyhole Dynamics, Laser Absorption, and Porosity in Additive Manufacturing of Ti-6Al-4V

April 29, 2024
Author(s)
Arash Samaei, Joseph Leonor, zhengtao gan, Zhongsheng Sang, Xiaoyu Xie, Brian Simonds, Wing Kam Liu, Gregory Wagner
Metal 3D printing involves a multitude of operational and material parameters that exhibit intricate interdependencies, which pose challenges to real-time process optimization, monitoring, and controlling. The dynamic behavior of the laser-induced melt

Ability to simulate laser absorption and melt pool dynamics in solid aluminum: results and insights from the 2022 asynchronous AM-Bench challenge

February 1, 2024
Author(s)
Brian Simonds, Jack Tanner, Alexandra Artusio-Glimpse, Niranjan Parab, Cang Zhao, Tao Sun, Paul A. Williams
The 2022 Asynchronous AM-Bench challenge was designed to test the ability of simulations to accurately predict laser power absorption as well as various melt pool behaviors (width, depth, and solidification) during laser melting of solid metal during

Deep learning approaches for time-resolved laser absorptivity prediction

January 5, 2024
Author(s)
Runbo Jiang, John Smith, Yu-Tsen Yi, Tao Sun, Brian Simonds, Anthony D. Rollett
The quantification of the amount of absorbed light is essential for understanding laser-material interactions and melt pool dynamics in order to minimize defects in additive manufactured metal components. The geometry of a vapor depression, also known as a

NIST efforts in extreme-ultraviolet metrology

November 21, 2023
Author(s)
Charles S. Tarrio, Steven Grantham, Rob Vest, Thomas A. Germer, Bryan Barnes, Stephanie Moffitt, Brian Simonds, Matthew Spidell
For several decades, the National Institute of Standards and Technology (NIST) has actively supported metrology programs for extreme ultraviolet (EUV) lithography. We will describe our existing programs in optics lifetime, reflectometry, and radiometry

High-Power Radiation-Pressure-based Laser Metrology Using an Electrostatic Force Balance

September 11, 2023
Author(s)
Brian Simonds, Kyle Rogers, Sven Schulze, David Newell, Gordon Shaw, John Lehman, Paul A. Williams
A primary standard electrostatic force balance has been integrated into a multiple-reflection radiation pressure-based laser power meter capable of measuring kilowatts of optical power. We present optical power data at 0.1 kW, 1 kW, 2 kW, and 5 kW with the

Laser Power Accuracy of Additive Manufacturing Systems - A Round Robin Study

September 11, 2023
Author(s)
Brian Simonds, Kyle Rogers, Paul A. Williams
High power lasers are at the core of metal additive manufacturing (AM) systems and the accurate delivery of laser energy is critical to part performance. We have performed a round robin style survey of U.S. AM equipment across industry, academia, and

Radiation Pressure-based Laser Metrology Implementing an Electrostatic Force Balance

December 12, 2022
Author(s)
Brian Simonds, Kyle Rogers, Sven Schulze, David Newell, Gordon Shaw, Paul A. Williams, John Lehman
A primary standard force sensor and laser power meter are combined to achieve laser power traceability to Planck's constant by means of radiation pressure. We assess the statistical uncertainty for measurements of 1 kW, 2 kW, and 5 kW using an

Modes of laser melting in additive manufacturing of metals

October 20, 2022
Author(s)
Cang Zhao, Bo Shi, Shuailei Chen, Tao Sun, Brian Simonds, Anthony Rollett
In the laser powder bed fusion additive manufacturing of metals, extreme thermal conditions create many highly dynamic physical phenomena, such as vaporization and recoil, Marangoni convection, and protrusion and keyhole instability. Collectively, however

Are additive manufacturing systems accurately delivering laser power?

September 12, 2022
Author(s)
Brian Simonds, Kyle Rogers, Paul A. Williams
At the core of most metal additive manufacturing (AM) systems is a high-power (100-1000 W) laser. The delivered light energy drives the entire AM process by determining the melt volume and maximum temperature, which ultimately dictates solidification and

Laser Spot Welding of Additive Manufactured 304L Stainless Steel

February 1, 2022
Author(s)
Brian Simonds, Cheryl Hawk, Stephen Liu, Daniel Javernick, Robin Pacheco, Michael Brand, Jack R. Tanner, Greg Vigil
The goal of this work is to understand if an additively manufactured 304L stainless steel exhibited similar spot welding behavior as wrought 304L stainless steel. Due to the many differences between an additively manufactured component and wrought product

In situ absorption synchrotron measurements, predictive modeling, microstructural analysis, and scanning probe measurements of laser melted Ti-6Al-4V single tracks for additive manufacturing applications

December 29, 2021
Author(s)
Nicholas Derimow, Edwin Schwalbach, Jake Benzing, Jason Killgore, Aly Artusio-Glimpse, Nik Hrabe, Brian Simonds
In this work, the fundamental processing-structure-property (PSP) relationships that govern laser-based additive manufacturing were investigated with the Ti-6Al-4V alloy. X-ray synchrotron imaging carried out in conjunction with in-situ integrating sphere

The causal relationship between melt pool geometry and energy absorption measured in real time during laser-based manufacturing

December 16, 2021
Author(s)
Brian Simonds, Jack R. Tanner, Aly Artusio-Glimpse, Paul A. Williams, Niranjan Parab, Cang Zhao, Tao Sun
During laser powder bed fusion additive manufacturing, a protean pool of molten metal governs a complex energy absorption process as it presents as either a highly reflective surface, a deeply absorbing cavity (a keyhole), or some amalgamation thereof. To

In Situ Monitoring of Cu/Al Laser Welding using Laser Induced Fluorescence

September 10, 2020
Author(s)
Brian Simonds, Tran N. Tran, Paul A. Williams
We investigate laser spot welding of 200 µm thick Cu and Al foils using laser-induced fluorescence (LIF). The key to strong Cu/Al welds is limited intermetallic compound formation through controlled molten metal interaction time. For laser lap welds, Cu in

Simultaneous High-speed X-ray Transmission Imaging and Absolute Dynamic Absorptance Measurements during High-power Laser-metal Processing

September 10, 2020
Author(s)
Brian Simonds, Jack R. Tanner, Alexandra B. Artusio-Glimpse, Paul A. Williams, Niranjan Parab, Cang Zhao, Tao Sun
During high-power laser metal processing, the absorbed light is intimately related to the molten metal cavity shape. For the first time, we directly and simultaneously observe this relationship by implementing state-of-the-art techniques of high-speed x

Measurement of thermophysical properties of NIST SRM 1155a (Cr18-Ni12-Mo2)

December 9, 2019
Author(s)
Peter Pichler, Brian Simonds, Jeffrey W. Sowards, Gernot Pottlacher
SRM 1155a is an AISI 316 stainless steel (Cr18-Ni12-Mo2) and Standard Reference Material (SRM) intended for use with test methods for elemental analysis. At the National Institute of Standards and Technology (NIST) in Boulder, Colorado dynamic absorptance