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1. Correcting flat mirrors with surface stress: analytical stress fields

   https://doi.org/10.1364/JOSAA.35.001705  

   Chalifoux, Brandon D. ; Heilmann, Ralf K. ; Schattenburg, Mark L. ( September 2018 , Journal of the Optical Society of America A)
2. A surface flattening method for characterizing the surface stress, drained Poisson's ratio and diffusivity of poroelastic gels

   https://doi.org/10.1039/D1SM00513H  

   Liu, Zezhou ; Hui, Chung-Yuen ; Jagota, Anand ; Gong, Jian Ping ; Kiyama, Ryuji ( August 2021 , Soft Matter)

   When a poroelastic gel is released from a patterned mold, surface stress drives deformation and solvent migration in the gel and flattens its surface profile in a time-dependent manner. Specifically, the gel behaves like an incompressible solid immediately after removal from the mold, and becomes compressible as the solvent is able to squeeze out of the polymer network. In this work, we use the finite element method (FEM) to simulate this transient surface flattening process. We assume that the surface stress is isotropic and constant, the polymer network is linearly elastic and isotropic, and that solvent flow obeys Darcy's law. The short-time and long-time surface profiles can be used to determine the surface stress and drained Poisson's ratio of the gel. Our analysis shows that the drained Poisson's ratio and the diffusivity of the gel can be obtained using interferometry and high-speed video microscopy, without mechanical measurement. 

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3. The Impact of Topography and Eddy Parameterization on the Simulated Southern Ocean Circulation Response to Changes in Surface Wind Stress

   https://doi.org/10.1175/JPO-D-20-0142.1  

   Kong, Hailu ; Jansen, Malte F. ( March 2021 , Journal of Physical Oceanography)

   null (Ed.)

   Abstract It remains uncertain how the Southern Ocean circulation responds to changes in surface wind stress, and whether coarse-resolution simulations, where mesoscale eddy fluxes are parameterized, can adequately capture the response. We address this problem using two idealized model setups mimicking the Southern Ocean: a flat-bottom channel and a channel with moderately complex topography. Under each topographic configuration and varying wind stress, we compare several coarse-resolution simulations, configured with different eddy parameterizations, against an eddy-resolving simulation. We find that 1) without topography, sensitivity of the Antarctic Circumpolar Current (ACC) to wind stress is overestimated by coarse-resolution simulations, due to an underestimate of the sensitivity of the eddy diffusivity; 2) in the presence of topography, stationary eddies dominate over transient eddies in counteracting the direct response of the ACC and overturning circulation to wind stress changes; and 3) coarse-resolution simulations with parameterized eddies capture this counteracting effect reasonably well, largely due to their ability to resolve stationary eddies. Our results highlight the importance of topography in modulating the response of the Southern Ocean circulation to changes in surface wind stress. The interaction between mesoscale eddies and stationary meanders induced by topography requires more attention in future development and testing of eddy parameterizations. 

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4. Application of Stress Sensing Coatings on Metal Substrates with a Sub-surface Notch

   https://doi.org/10.2514/6.2019-1969  

   Esteves, Remelisa ; Hoover, Ryan ; Vo, Khan ; Jahan, Sanjida ; Haldar, Sandip ; Raghavan, Seetha ( January 2019 , AIAA Scitech 2019 Forum)
5. Effect of Prior Surface Textures on the Resulting Roughness and Residual Stress during Bead-Blasting of Electron Beam Melted Ti-6Al-4V

   https://doi.org/10.3390/cryst12030374  

   Rifat, Mustafa ; Basu, Saurabh ; De Meter, Edward C. ; Manogharan, Guha ( March 2022 , Crystals)

   The finishing of additive manufactured (AM) components is crucial for endowing them with fatigue resistance. Unfortunately, current AM processes naturally promote anisotropic surface characteristics that make it challenging to optimize finishing processes. In this study, bead-blasting is explored as a process for finishing Electron Beam Melted (EBM) Ti-6Al-4V. The effects of anisotropic roughness characteristics on the mechanics of bead-blasting are delineated using surface texture measurements via optical profilometry and residual stress measurements via X-ray diffraction. As-received surfaces resulting from AM, as well as those that have been Electrical Discharge Machined (EDM), are studied. It is seen that pre-processed roughness textures heavily influence the final textures and residual stresses. These linkages are quantified using a plasticity index as the governing metric—a rougher surface features a larger plastic index, which results in comparatively greater evolution of its texture characteristics than a smoother surface after equivalent bead-blasting treatments. The mechanics of this evolution are delineated using energy-controlled indentation as a model representing a single impact in bead-blasting. It is seen that rougher surfaces featuring complex textures in as-received states also produce complex stress states featuring a greater level of locally tensile stresses during indentation compared with smoother surfaces. Approaches to address these complications are proposed that can potentially transform a printed, non-functional surface into one that is optimized for fatigue resistance.

    

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