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

湿机械荷载下木制文化遗产结构行为的建模和表征

• 批准号: 240287377
• 负责人: Professor Dr.-Ing. Michael Kaliske
• 金额: --
• 依托单位: Institut für Statik und Dynamik der Tragwerke
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/240287377?language=en
• 关键词: Modelling; Characterization; Structural; Behaviour; Wooden

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.

木制文化遗产，例如历史板块绘画，家具和音乐乐器通常会显示出较大的变形和裂缝。原因是由于室内气候和机械载荷的每日和季节性变化而发生的潮流负荷，例如由张力的仪器串产生。在项目的框架内，应启用对这些负载下木结构的长期分析，因此，在保护背景下为决策而开发了一种客观工具。可以确定和研究临界负载以及恢复度量对结构响应的影响，而不会影响独特的原始物体。通过预测未来的负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，该分析工具可以对保存历史木制文化遗产的保存做出重要贡献。对于有限元元素方法对木制对象进行全面的长期结构分析，有效的方法的开发对于有效的方法是必要的。为了在长期范围和高度非线性材料模型中模拟大型结构，需要大大降低计算成本。因此，开发了一种用于细胞，天然材料木材的时间多尺度方法，多物理特征以及潮汐和机械外部负载。在项目中开发了木材的时间和水分依赖性行为所需的本构材料配方。借助适当的实验，研究了水分引起的应力，蠕变效应以及粘合接头和表面涂层对水分传输和机械结构行为的影响。到目前为止，在历史对象中使用的特征性木材物种，历史胶水和表面涂层的特征性木材，历史胶水和表面涂层的微尺度水分转运的时间，水分和载荷依赖性的蠕变和机械含量效应的材料特性（用于自然变异）在实验上确定。得出适当的物理定律，并在这些实验的帮助下开发了材料模型。新开发的方法和模型用于历史对象的数值模拟和结构分析。多物理载荷和材料特征对负载行为的影响是通过有限元素脉冲捕获的。实验和模拟的结果用于定义博物馆内房间气候的合理变化，这些变化不会造成或加强对文化遗产的损害，这是保护者评估气候影响并预测历史对象的结构长期行为的潜在工具。