Compression After Impact Experiments on Thin Face Sheet Honeycomb Core Sandwich Panels

Indentation of sandwiches using a plate model with variable kinematics and fixed degrees of freedom

“…A mesoscale model is chosen considering that, as claimed e.g. in [31], this kind of model is known for being more accurate and computationally advantageous than structural scale models assuming cracks as hard discontinuities. With this approach, the discretely damaged medium is replaced with a continuous homogeneous medium, which is equivalent from an energy standpoint, and which incorporates into the expression of the strain energy damage indicators, computed as the homogenised result of damage micromodels.…”

“…Consider the 152.4 Â 152.4 mm 2 sandwich plates with honeycomb core analysed by McQuigg [31]. The skins of the sandwich construction are obtained using two plies of style 7781 plain woven E-glass fabric with 40% epoxy resin content, whose strength and modulus in the warp and fill direction are 413.6 MPa and 20.7 GPa, respectively, for compressive loading, and 372.3 MPa and 20.7 GPa, respectively, for tensile loading.…”

“…But instead of considering a healthy material, a damaged material is considered at each time step because the continuum damage mesomechanic model by Ladevèze et al [29], [30] is used inside the VK-ZZ model, along with the properties of core provided by the preliminary FEA carried apart. A mesoscale model was chosen because, as claimed in [31], this kind of models is more accurate and computationally advantageous than structural scale ones, which consider cracks as hard discontinuities. The mesoscale model provides a modified expression of the strain energy that accounts for the effects of the damage on the microscale.…”

Indentation of Sandwiches Using a Refined Zig-Zag Model and a Mesoscale Damage Model

“…To overcome this drawback, here the damage mesomodel (MSD) by Ladevèze et al [27]- [28] is chosen, considering that this kind of models has an accuracy comparable to that of the above mentioned models, but an improved efficiency, as claimed by McQuigg [29].…”

“…It considers the effects of the damages on the microscale through a modified expression of the strain energy. This damage model was chosen because, as explained in [29], it provides greatly accurate results with a smaller computational burden than structural scale models.…”