Stability of a support sandwich panel with a detached fresco: An experimental, analytical, and numerical evaluation

The conservation of detached frescoes commonly relies on their transfer onto lightweight support systems, such as honeycomb sandwich panels. This intervention leads to a multilayer configuration (support, epoxy resin, fresco), that affects the buckling response under in-plane compressive loading, amplifying instability, and compromising integrity of detached fresco. The study investigates stability of honeycomb panel supporting a fresco through an integrated experimental analytical-numerical approach, focusing on fresco layer on overall stability. Edge-wise compression tests were performed on panels with a plaster layer simulating the fresco. Digital Image Correlation technique was employed to capture both in-plane and out-of-plane deformations. An analytical model was developed to evaluate the sensitivity of the support stability to the presence of fresco and epoxy resin layers. Finite Element analyses were performed using both a two-dimensional multilayer plate model and a three-dimensional model to assess accuracy and computational efficiency in linear buckling analyses. Sensitivity analysis to the panel stability demonstrated influence of the fresco in the critical load. The findings indicate that additional structural support is required to prevent collapse under self-weight in larger panels. Here, a reliable framework for assessing the buckling response of support panels with frescoes is investigated, guiding the design of effective conservation solutions.