Tunder89
Guest
Good morning.
I'm a researcher. I am modeling on abaqus 2022 a sandwich panel consisting of three layers: two very thin external layers (skin) and a thick internal layer (core). the core is of alveolar type, therefore the panel is of the type honeycomb, with constituent elements the core made of wood with cylindrical geometry and section in the shape of a circular crown, placed with their longitudinal axis perpendicularly on the panel plane. These elements are untied and untied. skins are composed of a fibroreinforzate composite material. the thickness of the skins is 0.6 mm, while the core is 13,1 mm. the skins are glued with rings through an epoxy resin. each wooden ring is glued individually with the skins forming the panel.
the panel is subject to three-point bending tests. the dimensions of the panel to be tested are: total length 300 mm, distance between the supports 220 mm, panel width 35 mm. the supports of the beam and the load cell are shaped as cylindrical rigid shells with diameters of 15 mm, to which the boundary conditions are applied via reference points (rp). constraints were imposed on the supports, while the load cell is free to transverse direction to the longitudinal direction of the sample.
the skins and rings of the core were modeled using 3d elements, with the extrude function. for each element has been imposed a system of local coordinates. in the model the skins were bound by cohesive contact interaction with the individual rings, specifying the coefficients of rigidity k equal to 150. through the damage option I specified "damage evolution" with "quadratic traction" criterion and maximum rated stress equal to 36. in evolution damage has chosen type "energy" and "linear" defining a fracture energy equal to 12.5. the viscosity of 0.0001 was specified.
Moreover, in contact surfaces between load cell and skin, as well as for supports and skin, a hard contact interaction and tangential friction with a penalty value of 0.1 has been inserted. the same was done within the core, ie in the contact zones between rings. Composite skins and core rings are shaped using a linear 3d brick element with eight knots (c3d8r).
the problem I have encountered is that, once the model is executed, the response in terms of normal tensions is not symmetric. In particular, along the base, the distribution of tensions is not symmetric, which should not happen. I can't understand why. This problem does not arise when I impose a type of interaction tied between the skins and rings constituting the core.
I'm a researcher. I am modeling on abaqus 2022 a sandwich panel consisting of three layers: two very thin external layers (skin) and a thick internal layer (core). the core is of alveolar type, therefore the panel is of the type honeycomb, with constituent elements the core made of wood with cylindrical geometry and section in the shape of a circular crown, placed with their longitudinal axis perpendicularly on the panel plane. These elements are untied and untied. skins are composed of a fibroreinforzate composite material. the thickness of the skins is 0.6 mm, while the core is 13,1 mm. the skins are glued with rings through an epoxy resin. each wooden ring is glued individually with the skins forming the panel.
the panel is subject to three-point bending tests. the dimensions of the panel to be tested are: total length 300 mm, distance between the supports 220 mm, panel width 35 mm. the supports of the beam and the load cell are shaped as cylindrical rigid shells with diameters of 15 mm, to which the boundary conditions are applied via reference points (rp). constraints were imposed on the supports, while the load cell is free to transverse direction to the longitudinal direction of the sample.
the skins and rings of the core were modeled using 3d elements, with the extrude function. for each element has been imposed a system of local coordinates. in the model the skins were bound by cohesive contact interaction with the individual rings, specifying the coefficients of rigidity k equal to 150. through the damage option I specified "damage evolution" with "quadratic traction" criterion and maximum rated stress equal to 36. in evolution damage has chosen type "energy" and "linear" defining a fracture energy equal to 12.5. the viscosity of 0.0001 was specified.
Moreover, in contact surfaces between load cell and skin, as well as for supports and skin, a hard contact interaction and tangential friction with a penalty value of 0.1 has been inserted. the same was done within the core, ie in the contact zones between rings. Composite skins and core rings are shaped using a linear 3d brick element with eight knots (c3d8r).
the problem I have encountered is that, once the model is executed, the response in terms of normal tensions is not symmetric. In particular, along the base, the distribution of tensions is not symmetric, which should not happen. I can't understand why. This problem does not arise when I impose a type of interaction tied between the skins and rings constituting the core.