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Molding samples from gels
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Molding samples from gels
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Photoelastic samples can also be cast from more common materials than [urethane](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/molding-urethane). For example gelatin is a very good photoelastic material, with a high photoelastic constant, which means a small stress induces a large photoelastic effect (Kuske & Robinson, "Photoelastic Stress Analysis"). Gelatin is most likely the most used photoelastic gel but many others like agar or konjac exist ([Tomlinson and Taylor](https://www.spiedigitallibrary.org/journals/Optical-Engineering/volume-54/issue-8/081208/Photoelastic-materials-and-methods-for-tissue-biomechanics-applications/10.1117/1.OE.54.8.081208.short?SSO=1))
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Photoelastic samples can also be cast from more common materials than [urethane](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/molding-urethane). For example gelatin is a very good photoelastic material, with a high photoelastic constant, which means a small stress induces a large photoelastic effect (Kuske & Robinson, "Photoelastic Stress Analysis"). Gelatin is most likely the most used photoelastic gel but many others like agar or konjac exist ([Tomlinson and Taylor](https://www.spiedigitallibrary.org/journals/Optical-Engineering/volume-54/issue-8/081208/Photoelastic-materials-and-methods-for-tissue-biomechanics-applications/10.1117/1.OE.54.8.081208.short?SSO=1)).
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Making cross-linked gelatin discs
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Making cross-linked gelatin discs
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... | @@ -17,9 +17,11 @@ Making cross-linked gelatin spheres |
... | @@ -17,9 +17,11 @@ Making cross-linked gelatin spheres |
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Gelatin spheres can be made by dripping a hot gelatin solution in a cold oil (e.g decane). To make sure the droplet remains spherical, it is important that the Bond number (the ratio of the weight of the droplet and surface tension) is low. This can be achieved by making sure the droplets are sufficiently small (by using a very small nozzle) and to avoid using surfactants. The droplet size can be made even smaller by applying a coaxial air flow. This air flow along the nozzle allows gelatin particles to be made with sizes ranging from 2.3 to 7 mm ([Workamp et al](https://aip.scitation.org/doi/abs/10.1063/1.4972587)). To ensure the droplets are fully solidified before touching each other (which could lead to merging), it is convenient to have a sufficiently long tube of cold oil in which the droplets slowly solidify while settling to the bottom.
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Gelatin spheres can be made by dripping a hot gelatin solution in a cold oil (e.g decane). To make sure the droplet remains spherical, it is important that the Bond number (the ratio of the weight of the droplet and surface tension) is low. This can be achieved by making sure the droplets are sufficiently small (by using a very small nozzle) and to avoid using surfactants. The droplet size can be made even smaller by applying a coaxial air flow. This air flow along the nozzle allows gelatin particles to be made with sizes ranging from 2.3 to 7 mm ([Workamp et al](https://aip.scitation.org/doi/abs/10.1063/1.4972587)). To ensure the droplets are fully solidified before touching each other (which could lead to merging), it is convenient to have a sufficiently long tube of cold oil in which the droplets slowly solidify while settling to the bottom.
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![Gelspheres](uploads/5492c9ade2e6f329f957ec9147d22150/Gelspheres.PNG)
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![Gelspheres](uploads/5492c9ade2e6f329f957ec9147d22150/Gelspheres.PNG)
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Gelatin spheres made using the technique published by ([Workamp et al](https://aip.scitation.org/doi/abs/10.1063/1.4972587)).
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Gelatin spheres made using the technique published by ([Workamp et al](https://aip.scitation.org/doi/abs/10.1063/1.4972587)).
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![PEResponseGelSuspension](uploads/dc8a7fd217686de833f13ea249ea1fcd/PEResponseGelSuspension.PNG)
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![PEResponseGelSuspension](uploads/dc8a7fd217686de833f13ea249ea1fcd/PEResponseGelSuspension.PNG)
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Photoelastic response of a suspension of bidisperse gelatin spheres in a Couette geometry. For details see [Workamp et al](https://doi.org/10.1051/epjconf/201714003020).
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Photoelastic response of a suspension of bidisperse gelatin spheres in a Couette geometry. For details see [Workamp et al](https://doi.org/10.1051/epjconf/201714003020).
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[<go back to home](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/home) |
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[<go back to home](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/home) |
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