Modelling and Characterization of the Structural Behaviour of Wooden Cultural Heritage under Hygro-mechanical Loading

木制文化遗产，如历史性的板画、家具和乐器，往往会出现大的变形和裂缝。原因是由于室内气候的每日和季节性变化以及机械负载（例如，由乐器的张紧弦引起）而产生的湿度负载。在该项目的框架内，将能够对这些荷载下的木结构进行长期分析，从而为保护方面的决策制定一个客观的工具。可以确定和研究临界载荷以及恢复措施对结构响应的影响，而不影响独特的原始对象。该分析工具通过预测未来荷载和气候变化下的长期行为，并通过定义可容忍的气候条件限制，可以为历史木制文化遗产的保护做出重要贡献。对于木构件的长期结构分析，需要开发有效的方法来考虑随时间变化的气候荷载和结构响应。为了能够模拟长期范围内的大型结构和高度非线性的材料模型，需要大大降低计算成本。因此，一个时间的多尺度方法的细胞，天然材料木材，多物理特性和hygrical和机械的外部loadings.The所需的本构材料配方的木材的时间和水分依赖性的行为的描述内开发的项目。湿致应力，蠕变效应以及粘接接头和表面涂层对水分传输和机械结构行为的影响进行了研究与适当的实验的帮助。到目前为止，广泛未知的材料性能的时间，水分和负载依赖的蠕变和机械吸附效应，以及微观尺度的水分传输的特征木材品种，历史胶水和表面涂层，在历史的对象，实验确定考虑自然变化。在这些实验的帮助下，导出了相应的物理规律，建立了材料模型，并将这些新的方法和模型用于历史文物的数值模拟和结构分析。通过有限元分析捕获多物理载荷和材料特性对承载行为的影响。实验和模拟的结果被用来定义博物馆内的房间气候的合理变化，不会导致或加剧对文化遗产的破坏，这是一个潜在的工具，保护者评估气候的影响，并预测结构的长期行为的历史对象。

Wooden cultural heritage, like historical panel paintings, furniture and music instruments often show damages as large deformations and cracks. The reason are hygrical loadings, that occur due to daily and seasonal variation of the room climate and mechanical loadings, e.g. resulting from tensioned strings of instruments. Within the framework of the project, the long-term analysis of wooden structures under these loadings shall be enabled and, thus, an objective tool developed for decision making in the context of conservation. Critical loadings as well as effects of restoration measures on the structural response can be determined and investigated, without influencing the unique original objects. By predicting the long-term behaviour under future loadings and climate change and by defining tolerable climate conditional limits, the analysis tool can be an important contribution to the preservation of the historical wooden cultural heritage.For the comprehensive long-term structural analysis of wooden objects by the Finite-Element-Method, the development of efficient methods is necessary to consider time-dependent climate loads and structural responses. To enable the simulation of large structures in the long-term range and highly non-linear material models, the computational costs need to be considerably reduced. Thus, a temporal multiscale method for the cellular, natural material wood, the multi-physical characteristics and hygrical and mechanical external loadings is developed.The required constitutive material formulations for the description of the time- and moisture-dependent behaviour of wood are developed within the project. The moisture-induced stresses, creep effects as well as the influence of adhesive joints and surface coatings on moisture transport and mechanical structural behaviour are studied with the help of appropriate experiments. The, until now, widely unknown material properties for time-, moisture- and loading-dependent creep and mechano-sorptive effects as well as micro-scale moisture transport of characteristic wood species, historical glues and surface coatings, used in historical objects, are determined experimentally under consideration of the natural variation. Appropriate physical laws are derived and material models are developed with the help of these experiments.The newly developed methods and models are used for the numerical simulation and structural analysis of the historical objects. The influence of multi-physical loadings and material characteristics on the load-bearing behaviour is captured by means of Finite-Element-Analyses. The results of the experiments and simulations are used to define reasonable changes of room climate within museums that do not cause or intensify damages to the cultural heritage and with that are a potential tool for conservators to evaluate the influence of the climate and predict the structural long-term behaviour of historical objects.