Article
Optics
Kevin Rainey, Steve Gilbertson, Daniel Kalb, Thomas Beery
Summary: The study developed a method called Modulation Based Ranging (MBR) for directly measuring displacement of a moving surface in dynamic or high explosive driven experiments. It effectively overcame errors associated with integrating velocity history of objects undergoing non-radial flow, and demonstrated high accuracy in measuring displacement. The MBR technique showed excellent agreement with the Photonic Doppler Velocimetry (PDV) integrated velocity measurements in the absence of non-radial flow, and accurately measured true displacement of surfaces under strong non-radial components.
Article
Engineering, Mechanical
A. P. Simonov, I. V. Sergeichev
Summary: The direct impact method provides a higher sample deformation rate and reliable results for materials with low yield strength and hardening rate. This study proposes an alternative procedure for calculating the strain rate in order to improve accuracy of the direct impact method for a wide range of metals and alloys. The proposed method has been validated through finite element analysis and direct impact tests, and it qualitatively changes the shape of the stress-strain curve by adding an unloading area.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2024)
Article
Multidisciplinary Sciences
Xiao-He Wang, Wu Jing, Wen-Bo Zhang, Jiang-Hao Wang, Qing-Long Yun, Yi-Qing Wang, Sui Yi
Summary: This study investigates the energy dissipation characteristics in coal crushing under impact loads, focusing on the dynamic compression mechanical attributes from perspectives of energy and fragmentation's fractal dimensions. The findings highlight the significant escalation in fragmentation work for burst-prone coal samples compared to non-burst-prone samples, correlating with enhanced strain rates. The study also reveals the relationship between energy growth and the persistent escalation of fragmentation's fractal dimensions.
SCIENTIFIC REPORTS
(2023)
Article
Mechanics
S. Saraygord Afshari, Seid H. Pourtakdoust, B. J. Crawford, R. Seethaler, A. S. Milani
Summary: The study introduces a dynamic reliability evaluation method based on PDEM for analyzing the reliability of composite structures under uncertainties. A Back-Propagation Neural Network approach is used to identify nonlinear structural response in the case of large deformations. Experimental results validate the accuracy and applicability of the method.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Mechanical
Tomas Fila, Petr Koudelka, Jan Falta, Petr Zlamal, Vaclav Rada, Marcel Adorna, Stefan Bronder, Ondrej Jirousek
Summary: This paper introduces a new experimental method using an Open Hopkinson Pressure Bar (OHPB) instrumented with strain-gauges on both bars, combined with Digital Image Correlation (DIC) to accurately study the behavior of cellular materials under dynamic impact conditions. Experimental results show that a simple linear elastic model is sufficient for materials with viscoelastic bars, without the need for additional corrections.
INTERNATIONAL JOURNAL OF IMPACT ENGINEERING
(2021)
Article
Optics
William P. Mullins, Nazila Soleimani, Natalie Prince, Zachary A. Fussell, Michael R. Armstrong
Summary: Photon Doppler velocimetry (PDV) is a widely used diagnostic method in dynamic compression experiments. In this study, detailed measurements of the bidirectional reflectance distribution function for different surface preparations and materials are presented. Scattering theory and simulations are employed to accurately emulate the measured data, and a straightforward method to derive the average scattering distribution is introduced to optimize PDV signals.
OPTICAL ENGINEERING
(2022)
Article
Instruments & Instrumentation
Pinghan Chu, Velat Kilic, Mark A. Foster, Zhehui Wang
Summary: A time lens is described for expanding the dynamic range of photon Doppler velocimetry systems. The use of a four-wave-mixing time lens can slow down frequency shifts of PDV with a magnification factor M, allowing for a wider velocity measurement range. TL-PDV has been shown to be feasible and can open up new avenues for dynamic material experiments.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2021)
Article
Engineering, Industrial
Stanley Bovid, Micheal Kattoura, Allan Clauer, Anupam Vivek, Glenn Daehn, Stephen Niezgoda
Summary: The study found that using adhesive-backed overlays can increase peak pressures in laser shock peening, and the temporal characteristics are independent of the laser pulse width. A novel analytical model to predict shockwave pressures was proposed and validated with experimental data.
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
(2022)
Article
Chemistry, Analytical
Yunfei Mu, Wei Zhang, Ruiqi Shen, Yinghua Ye
Summary: This study used PDV and PVDF gauges to investigate the detonation growth of lead azide (LA) and discussed the three phases of detonation propagation in LA microcharges.
Article
Physics, Multidisciplinary
Xiao-Feng Shi, Dong-Jun Ma, Song-lin Dang, Zong-Qiang Ma, Hai-Quan Sun, An-Min He, Pei Wang
Summary: The photon Doppler velocimetry (PDV) spectrum is studied to determine particle parameters of ejecta from shock-loaded samples in a vacuum. A theoretical optical model is proposed to extract particle parameters directly from the PDV spectrum.
Article
Engineering, Chemical
Wanquan Deng, Zhen Li, Lei Ji, Linmin Shang, Demin Liu, Xiaobing Liu
Summary: This paper investigates the velocity distribution in the draft tube of a Francis pump turbine using laser Doppler velocimetry. The study finds that the velocity pulsation is directly related to the pressure pulsation and is also influenced by the cavitation coefficient.
Article
Cardiac & Cardiovascular Systems
Misun Pak, Takeshi Kitai, Atsushi Kobori, Yasuhiro Sasaki, Taiji Okada, Ryosuke Murai, Toshiaki Toyota, Kitae Kim, Natsuhiko Ehara, Makoto Kinoshita, Yutaka Furukawa
Summary: This study investigated the reliability of an algorithmic classification system using invasively measured left atrial pressure in a large-scale cohort. The results showed that the classification using echocardiographic parameters may be useful for detecting patients with normal left ventricular filling pressure, but may be limited for detecting elevated left ventricular filling pressure.
JACC-CARDIOVASCULAR IMAGING
(2022)
Article
Construction & Building Technology
Yijiao Huang, Xianfeng Wang, Min Sheng, Dawei Qin, Jun Ren, Xiaoqing Zhou, Jihua Zhu, Feng Xing
Summary: This study investigated the dynamic behavior of microcapsule-based self-healing concrete under impact loading. It found that the dynamic mechanical properties of the self-healing concrete exhibit strong strain-rate dependency, with compressive strength and strain energy density increasing with increasing strain rate. Significant differences in post-test damage patterns were observed between control and experimental groups. The dynamic increase factor (DIF) of the self-healing concrete increases logarithmically with strain rate, with a strain-rate sensitivity threshold at 25.7 s(-1). Empirical DIF relations were proposed for predicting material behavior under static and impact loading.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Physics, Multidisciplinary
Marta Pita-Vidal, Arno Bargerbos, Rok Zitko, Lukas J. Splitthoff, Lukas Grunhaupt, Jaap J. Wesdorp, Yu Liu, Leo P. Kouwenhoven, Ramon Aguado, Bernard van Heck, Angela Kou, Christian Kraglund Andersen
Summary: Spin qubits in semiconductors are a promising platform for scalable quantum computing devices, but achieving multiqubit interactions over extended distances is challenging. Superconducting spin qubits encoded in Andreev levels provide an alternative with intrinsic spin-supercurrent coupling. This study demonstrates an electrostatically defined quantum dot Josephson junction with a spin-split doublet ground state, allowing for qubit manipulation and investigating the qubit performance using direct spin manipulation. Coupling the Andreev spin qubit with a superconducting transmon qubit shows strong coherent qubit-qubit coupling, a crucial step towards a hybrid architecture combining the advantages of both superconducting and semiconductor qubits.
Article
Materials Science, Multidisciplinary
Puneeth Jakkula, Georg Ganzenmueller, Stefan Hiermaier
Summary: This study introduces a variation of the Hopkinson bar, called Direct Impact Tension Bar (DITB), which is well-suited for probing low-impedance materials at intermediate strain-rates. The DITB offers accurate force signals without detrimental oscillations, making it a reliable tool for studying strain-rate effects. Experimental results on polycarbonate specimens demonstrate the applicability of the DITB in dynamic tensile tests, providing high-quality data free from oscillations.
