# Tensile test and Poisson ratio calibration Classic List Threaded 4 messages Open this post in threaded view
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## Tensile test and Poisson ratio calibration

 Hi everyone, In my research I am trying to simulate an epoxy (Poisson ratio of epoxy is about 0,3 and Young modulus = 3 GPa). So during calibration with tensile test I faced a problem: axial Poisson's ratios Poisson_YY and Poisson_ZZ are too different. poisson_graph.pngIs it correct to use average Poisson ratio for calibration (Poisson_ave on picture) or am doing something wrong? Test sample is a cube box 7*7*7mm with AverageDeRadius="227e-6" and RandomRange="25%", so Cardinality is about 6,2 and ratio "microscale over macroscale" is more than recommended 20. Here are parts of my input file (TimeStep="3e-8" and there are 300000 iterations):          ...                         Also, I don't use _SetElasticProperty plugin, because it gives me wrong values (it gave me MicroYoungModulus = 83 GPa and RadiusRatio = 0,32 for CoordinationNumber = 6,183722 for the values of the macroparameters specified at the beginning) Is it OK? And is the calibration procedure that I use in general normal? Thanks
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## Re: Tensile test and Poisson ratio calibration

 Administrator Hello, ctrlc0ctrlv wrote In my research I am trying to simulate an epoxy (Poisson ratio of epoxy is about 0,3 and Young modulus = 3 GPa). So during calibration with tensile test I faced a problem: axial Poisson's ratios Poisson_YY and Poisson_ZZ are too different. Is it correct to use average Poisson ratio for calibration (Poisson_ave on picture) or am doing something wrong? I guess that you can improve the accuracy of your results by unclamping the "Boundary-xMin" set. The discrete element must be free to move in the Y and Z direction to match a perfect uniaxial tensile test. Kind regards, Damien.