Three-degrees-of-freedom measurement system for measuring straightness errors and their position based on the Faraday effect

Abstract Background The trend in miniaturisation of structural components and continuous development of more advanced crystal plasticity models point towards the need for understanding cyclic properties of engineering materials at the microscale. Though the technology of focused ion beam milling enables the preparation of micron-sized samples for mechanical testing using nanoindenters, much of the focus has been on monotonic testing since the limited 1D motion of nanoindenters imposes restrictions on both sample preparation and cyclic testing. Objective/Methods In this work, we present an approach for cyclic microcantilever bending using a micromanipulator setup having three degrees of freedom, thereby offering more flexibility. Results The method has been demonstrated and validated by cyclic bending of Alloy 718plus microcantilevers prepared on a bulk specimen. The experiments reveal that this method is reliable and produces results that are comparable to a nanoindenter setup. Conclusions Due to the flexibility of the method, it offers straightforward testing of cantilevers manufactured at arbitrary position on bulk samples with fully reversed plastic deformation. Specific microstructural features, e.g., selected orientations, grain boundaries, phase boundaries etc., can therefore be easily targeted.

Download Full-text

Average Modelling of a Dual Half Bridge Converter Modulated with Three Degrees of Freedom

IEEE Transactions on Transportation Electrification ◽

10.1109/tte.2021.3062443 ◽

2021 ◽

pp. 1-1

Author(s):

Fei Gao ◽

Ngoni Mugwisi ◽

Daniel J. Rogers

Keyword(s):

Degrees Of Freedom ◽

Three Degrees Of Freedom

Download Full-text

Galloping Stability and Wind Tunnel Test of Iced Quad Bundled Conductors considering Wake Effect

Discrete Dynamics in Nature and Society ◽

10.1155/2020/8885648 ◽

2020 ◽

Vol 2020 ◽

pp. 1-15

Author(s):

Xiaohui Liu ◽

Ming Zou ◽

Chuan Wu ◽

Mengqi Cai ◽

Guangyun Min ◽

...

Keyword(s):

Wind Tunnel ◽

Transmission Lines ◽

Degrees Of Freedom ◽

Wind Tunnel Test ◽

Aerodynamic Coefficients ◽

Wake Effect ◽

Aerodynamic Coefficient ◽

Set Up ◽

The Stability ◽

Three Degrees Of Freedom

A new quad bundle conductor galloping model considering wake effect is proposed to solve the problem of different aerodynamic coefficients of each subconductor of iced quad bundle conductor. Based on the quasistatic theory, a new 3-DOF (three degrees of freedom) galloping model of iced quad bundle conductors is established, which can accurately reflect the energy transfer and galloping of quad bundle conductor in three directions. After a series of formula derivations, the conductor stability judgment formula is obtained. In the wind tunnel test, according to the actual engineering situation, different variables are set up to accurately simulate the galloping of iced quad bundle conductor under the wind, and the aerodynamic coefficient is obtained. Finally, according to the stability judgment formula of this paper, calculate the critical wind speed of conductor galloping through programming. The dates of wind tunnel test and calculation in this paper can be used in the antigalloping design of transmission lines.

Download Full-text

Analysis and Optimization of a New Differentially Driven Cable Parallel Robot

Journal of Mechanisms and Robotics ◽

10.1115/1.4028931 ◽

2015 ◽

Vol 7 (3) ◽

Cited By ~ 7

Author(s):

Hamed Khakpour ◽

Lionel Birglen ◽

Souheil-Antoine Tahan

Keyword(s):

Kinematic Analysis ◽

Design Methodology ◽

Degrees Of Freedom ◽

Parallel Robot ◽

Cable Robot ◽

Proper Design ◽

Two Indices ◽

Three Degrees Of Freedom ◽

Cable Robots

In this paper, a new three degrees of freedom (DOF) differentially actuated cable parallel robot is proposed. This mechanism is driven by a prismatic actuator and three cable differentials. Through this design, the idea of using differentials in the structure of a spatial cable robot is investigated. Considering their particular properties, the kinematic analysis of the robot is presented. Then, two indices are defined to evaluate the workspaces of the robot. Using these indices, the robot is subsequently optimized. Finally, the performance of the optimized differentially driven robot is compared with fully actuated mechanisms. The results show that through a proper design methodology, the robot can have a larger workspace and better performance using differentials than the fully driven cable robots using the same number of actuators.

Download Full-text

In-situ high-pressure study of the ordered phase of ethyl propionate

Acta Crystallographica Section B Structural Science ◽

10.1107/s010876810603477x ◽

2007 ◽

Vol 63 (1) ◽

pp. 111-117 ◽

Cited By ~ 8

Author(s):

Roman Gajda ◽

Andrzej Katrusiak

Keyword(s):

High Pressure ◽

Degrees Of Freedom ◽

Molecular Volume ◽

Ethyl Propionate ◽

Intermolecular Contacts ◽

High Pressure Study ◽

Pressure Phase ◽

Three Degrees Of Freedom ◽

Volume Difference

Ethyl propionate, C5H10O2 (m.p. 199 K), has been in-situ pressure-frozen and its structure determined at 1.34, 1.98 and 2.45 GPa. The crystal structure of the new high-pressure phase (denoted β) is different from phase α obtained by lowering the temperature. The freezing pressure of ethyl propionate at 296 K is 1.03 GPa. The molecule assumes an extended chain s-trans–trans–trans conformation, only slightly distorted from planarity. The closest intermolecular contacts in both phases are formed between carbonyl O and methyl H atoms; however, the ethyl-group H atoms in phase β form no contacts shorter than 2.58 Å. A considerable molecular volume difference of 24.2 Å3 between phases α and β can be rationalized in terms of degrees of freedom of molecules arranged into closely packed structures: the three degrees of freedom allowed for rearrangements of molecules confined to planar sheets in phase α, but are not sufficient for obtaining a densely packed pattern.

Download Full-text