Finite element analysis of a scanning x‐ray microscope micropositioning stage

It is a scientific and engineering challenge to characterize materials under nonequilibrium conditions. In recent years, X-ray photon correlation spectroscopy (XPCS), a synchrotron-based coherent X-ray scattering technique, has been found useful in determining the timescales associated with various nonequilibrium processes, with detailed descriptions of the underlying processes lacking. Here, both static ultra small angle X-ray scattering (USAXS) and dynamic USAXS-based XPCS were used to investigate a transient structural change (a nonequilibrium process) associated with an isothermal anneal in a glass polymer composite system. While the bulk USAXS technique lacked the required sensitivity to detect the change in the microstructures, the local structural reorganization was apparent in the XPCS study. The structural changes were modeled using a three-dimensional finite element analysis approach and wave-propagation theory was used to simulate the resulting reciprocal-space coherent scattering intensity. Qualitative agreement was found between the modeling and experimental results, which validates that stress relaxation in the viscous polymer matrix was responsible for the observed changes. This analysis demonstrates that multi-physics modeling of complex systems can be used to interpret XPCS measurements of nonequilibrium processes.

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Effect of Argon-Purged Cooling on Generating Residual Stress in Oxide Scale Formed on Si-Containing Steels Examined by In Situ X-ray Diffraction and Finite Element Analysis

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.mt-maw2019003 ◽

2020 ◽

Vol 61 (1) ◽

pp. 136-141

Author(s):

Koji Sasaki ◽

Kazushi Hayashi ◽

Mikako Takeda ◽

Shohei Nakakubo ◽

Yohei Yamada ◽

...

Keyword(s):

Residual Stress ◽

Finite Element Analysis ◽

Finite Element ◽

Oxide Scale ◽

X Ray Diffraction ◽

Element Analysis ◽

X Ray

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Long, elliptically bent, active X-ray mirrors with slope errors <200 nrad

Journal of Synchrotron Radiation ◽

10.1107/s1600577517005422 ◽

2017 ◽

Vol 24 (3) ◽

pp. 615-621 ◽

Cited By ~ 3

Author(s):

Ioana T. Nistea ◽

Simon G. Alcock ◽

Paw Kristiansen ◽

Adam Young

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Free Electron Laser ◽

State Of The Art ◽

Optical Metrology ◽

Optical Surface ◽

High Quality ◽

Element Analysis ◽

Bending Performance ◽

X Ray

Actively bent X-ray mirrors are important components of many synchrotron and X-ray free-electron laser beamlines. A high-quality optical surface and good bending performance are essential to ensure that the X-ray beam is accurately focused. Two elliptically bent X-ray mirror systems from FMB Oxford were characterized in the optical metrology laboratory at Diamond Light Source. A comparison of Diamond-NOM slope profilometry and finite-element analysis is presented to investigate how the 900 mm-long mirrors sag under gravity, and how this deformation can be adequately compensated using a single, spring-loaded compensator. It is shown that two independent mechanical actuators can accurately bend the trapezoidal substrates to a range of elliptical profiles. State-of-the-art residual slope errors of <200 nrad r.m.s. are achieved over the entire elliptical bending range. High levels of bending repeatability (ΔR/R = 0.085% and 0.156% r.m.s. for the two bending directions) and stability over 24 h (ΔR/R = 0.07% r.m.s.) provide reliable beamline performance.

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