Influence of thin film thermal stress on a variable thickness layer in graded reflectivity mirror production

Author(s):  
S Scaglione ◽  
D Flori ◽  
L Caneve
Author(s):  
Rune Storesund ◽  
Alan Kropp

This forensic engineering (FE) study evaluated root cause errors associated with excessive differential settlements on a housing project constructed on top of a variable thickness layer of highly compressible clays. The structures were reported to have experienced differential settlements on the order of 2 to 10 in. across 40 ft. The FE study examined fundamental assumptions, granularity/resolution of the settlement and differential settlement analyses, and finalized grading plan vs. the conceptual grading plan used as a basis for the differential settlement predictions. The FE study found numerous discrepancies between the “idealized site” used as a basis of analysis and the “actual site” as constructed.


2019 ◽  
Vol 46 (8) ◽  
pp. 0802003
Author(s):  
周显新 Xianxin Zhou ◽  
辛博 Bo Xin ◽  
巩亚东 Yadong Gong ◽  
张伟健 Weijian Zhang ◽  
张海权 Haiquan Zhang

2019 ◽  
Vol 66 (3) ◽  
pp. 1308-1313 ◽  
Author(s):  
You-Hang Zhou ◽  
Jun Li ◽  
De-Yao Zhong ◽  
Xi-Feng Li ◽  
Jian-Hua Zhang

2006 ◽  
Vol 435 (1-2) ◽  
pp. 82-86 ◽  
Author(s):  
M. Gregor ◽  
A. Plecenik ◽  
T. Plecenik ◽  
M. Tomasek ◽  
P. Kus ◽  
...  

2015 ◽  
Vol 661 ◽  
pp. 156-161
Author(s):  
Cheng Hao Ko ◽  
Kuei Ying Chang ◽  
You Min Huang ◽  
Jih Run Tsai ◽  
Bang Ji Wang

An analytical thin film thickness model based on the geometry of a commercial vacuum coating system is proposed. This model can calculate the profiles of linear variable filters (LVFs), which are used to eliminate overlapping orders of spectra due to the use of a diffraction grating and which are fabricated using a local mask, producing a linearly variable thickness. While the filter transmits the first-order wavelength and blocks the second-order wavelength. The 75% and 25% relative thicknesses deviation between the evaporated film and the theoretical model is less than 5%, indicating good suitability for LVF design and fabrication.


1996 ◽  
Vol 441 ◽  
Author(s):  
Carrie Carter-Coman ◽  
Robert Bicknell-Tassius ◽  
April S. Brown ◽  
Nan Marie Jokerst

AbstractThin film compliant substrates can be used to extend the critical thickness in mismatched overlayers. A metastability model has been coupled with recent experimental strain relief data to determine the critical thickness of InGaAs epilayers grown on GaAs compliant substrates of variable thickness. The results of this model are also compared to other compliant substrate critical thickness models.


Author(s):  
Swarup Bag ◽  
M. Ruhul Amin

In the present work, the deformation behavior in metallic film subjected to ultra-short laser heating is investigated. Static thermo-elastic behavior is predicted for 100 nm thin film of either single layer or multiple layers. The temperature distribution is estimated from dual-phase lag non-Fourier heat conduction model. The maximum temperature after single pulse is achieved 730 K. The temperature profile for this pulse laser is used to compute elastic stress and distortion field following the minimization of potential energy of the system. In the present work, the simulation has been proposed by developing 3D finite element based coupled thermo-elastic model using dual phase lag effect. The experimental basis of transient temperature distribution in ultra-short pulse laser is extremely difficult or nearly impossible, the model results have been validated with literature reported thermal results. Since the temperature distribution due to pulse laser source varies with time, the stress analysis is performed in incremental mode. Hence, a sequentially coupled thermo-mechanical model is developed that is synchronized between thermal and mechanical analysis in each time steps of transient problem. The maximum equivalent stress is achieved 0.3 GPa. Numerical results show that the predicted thermal stress may exceeds the tensile strength of the material and may lead to crack or damage the thin film.


2007 ◽  
Vol 46 (10A) ◽  
pp. 6469-6473 ◽  
Author(s):  
Kazuya Yoshioka ◽  
Toshiyuki Sameshima ◽  
Tomoya Iwasaki ◽  
Kazushige Takechi

2016 ◽  
Vol 16 (9) ◽  
pp. 9756-9760 ◽  
Author(s):  
Hyung Yoon Kim ◽  
Jae Hyo Park ◽  
Ki Hwan Seok ◽  
Zohreh Kiaee ◽  
Hee Jae Chae ◽  
...  

Geophysics ◽  
1996 ◽  
Vol 61 (2) ◽  
pp. 365-372 ◽  
Author(s):  
Robert L. Parker

Fourier methods for potential fields have always been developed with the simplification that the calculation surface is a level plane. The Fourier approach can be extended to deal with an uneven observation surface. I consider the case of terrain correction for gravity surveys, in which the attraction of a variable‐thickness layer is calculated at points on its upper surface. The main idea is to use a power series in topographic height that is then converted into a series of convolutions. To avoid convergence problems, a cylindrical zone around the observer must be removed from the Fourier treatment and its contribution computed directly. The resultant algorithm is very fast: in an example based on a recent survey, the new method is shown to be more than 300 times faster than a calculation based on summing contributions from a column of material under each topographic grid point.


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