A partitioning strategy for the coupled hygromechanical analysis with application to wood structures of cultural heritage

Abstract

SUMMARYOne of the main causes for damage of panel paintings of cultural heritage is due to the environmental micro-climatic variations. Wood science and numerical modeling may help to analyze and calibrate restoration interventions, to predict the behavior of the artwork, taking into account the individual painted panels and the conservation environment. In this article, a partitioning numerical strategy is proposed to predict by simulation the behavior of such artworks. It is based on a multiphysics partition focusing on the interactions between the different physics that are described in a thermodynamical framework. It is applied to the case study of Mona Lisa, modeled as a strongly coupled hygromechanical structure. The strategy is designed to couple two different modelings: a plate model for the mechanical behavior of the panel and 1D transverse diffusion for the moisture evolution.

Kinetic analysis of poplar wood properties by thermal modification in conventional oven

“…Many questions about the behaviour of wooden material during aging are still unanswered; wood researchers are more and more investigating cultural heritage problems (Marcon 2009, Dureisseix & Marcon 2011). Indeed, because it is often impossible to perform mechanical tests on wood from the cultural heritage, it is practically very difficult to describe the effect of aging on wood.…”

Modelling wooden cultural heritage. The need to consider each artefact as unique as illustrated by the Cannone violin

“…The mass transfer of water in hygroscopic materials such as wood depends on the diffusion of bound water through cell walls and of water vapour in the lumens, both being in equilibrium [33][34][35]. At the macroscopic scale, the overall effect is often modelled as a global diffusion with a unique diffusivity tensor D [11] containing the mass diffusion coefficients in the three anatomical directions. The varnished surface was supposed as not exchanging moisture (impervious boundary condition), while the non-coated face of the boundary tends to the computed equilibrium moisture content.…”

“…Anisotropic behaviour of wood, moisture gradients as well as asymmetric moisture adsorption in wooden cultural heritage is a large problem in the formation and grow of damage [3,4]. Approaches to measure and model the role of moisture gradients, constrained deformations, and resulting stresses have been undertaken since two decades in the field of panel paintings [5][6][7][8][9][10][11][12][13]. These research works were recently extended to musical instruments [14], timber structures [15], and waterlogged wood [16].…”

Mechanical study of a support system for cupping control of panel paintings combining crossbars and springs

“…The wooden support of this triptych, like the supports of many Italian panel paintings, especially in Central Italy during late 13th, 14th and early 15th centuries, was made of boards of poplar (Populus alba L.) [9,11], glued along their edges to form the planking. For this species, air-dry density ρ o ranges between 390 and 460 kg.m-3 [6,12].…”

“…Cracking with a large number of micro-cracks may indeed reduce the overall macroscopic stiffness. There is locally a stress redistribution that leads to a crack network [12]. Taking into account the ageing effect, the additional stiffness is not an issue, but renders the model more difficult to manage (with the requirement for a further new constitutive parameter to be estimated).…”