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Finite Element simulations of rubbers and biological soft tissue usually assume that the material being deformed is slightly compressible. It is shown here that in shearing deformations the corresponding normal stress distribution can exhibit extreme sensitivity to changes in Poissons ratio. These changes can even lead to a reversal of the usual Poynting effect. Therefore the usual practice of arbitrarily choosing a value of Poissons ratio when numerically modelling rubbers and soft tissue will, almost certainly, lead to a significant difference between the simulated and actual normal stresses in a sheared block because of the difference between the assumed and actual value of Poissons ratio. The worrying conclusion is that simulations based on arbitrarily specifying Poissons ratio close to 1/2 cannot accurately predict the normal stress distribution even for the simplest of shearing deformations. It is shown analytically that this sensitivity is due to the small volume changes which inevitably accompany all deformations of rubber-like materials. To minimise these effects, great care should be exercised to accurately determine Poissons ratio before simulations begin.
Most materials exhibit positive Poissons ratio (PR) values but special structures can also present negative and, even rarer, zero (or close to zero) PR. Null PR structures have received much attention due to their unusual properties and potential app
We present first-principles calculations of elastic properties of multilayered two-dimensional crystals such as graphene, h-BN and 2H-MoS2 which shows that their Poissons ratios along out-of-plane direction are negative, near zero and positive, respe
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Silicon dioxide or silica, normally existing in various bulk crystalline and amorphous forms, is recently found to possess a two-dimensional structure. In this work, we use ab initio calculation and evolutionary algorithm to unveil three new 2D silic