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，如历史版画、家具和乐器，经常会出现大变形和裂缝等损坏。原因是湿度负荷，这是由于室内气候和机械负荷的日常和季节变化而发生的，例如。由于乐器弦拉紧而产生的。在该项目的框架内，应能够对这些载荷下的木结构进行长期分析，从而为保护方面的决策开发客观工具。可以确定和研究临界载荷以及修复措施对结构响应的影响，而不会影响独特的原始物体。通过预测未来载荷和气候变化下的长期行为并定义可容忍的气候条件限制，该分析工具可以为保护历史木制文化遗产做出重要贡献。对于木制物体的全面长期结构分析通过有限元方法，开发有效的方法对于考虑与时间相关的气候载荷和结构响应是必要的。为了能够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，开发了一种针对细胞、天然材料木材、多物理特性以及湿度和机械外部载荷的时间多尺度方法。用于描述木材的时间和湿度依赖性行为所需的构成材料配方是在该项目。通过适当的实验，研究了湿气引起的应力、蠕变效应以及粘合接头和表面涂层对湿气传输和机械结构行为的影响。迄今为止，人们对历史物品中使用的与时间、湿度和负载相关的蠕变和机械吸附效应以及特征木材品种、历史胶水和表面涂层的微尺度水分传输的材料特性还知之甚少。在考虑自然变化的情况下通过实验确定。在这些实验的帮助下，导出了适当的物理定律并开发了材料模型。新开发的方法和模型用于历史物体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。实验和模拟的结果用于定义博物馆内室内气候的合理变化，这些变化不会对文化遗产造成或加剧损害，并且是保护者评估气候影响和预测结构长期影响的潜在工具。 -历史对象的术语行为。