Physical change of paintings on a textile base caused by mechanical loads: Investigations on origin and development of damage

由于公共和私营部门的特别展览的增加，近年来艺术品运输的数量显著增加。偶尔，这会导致易碎物品的明显损坏，但最重要的是，这也会导致微观上的微小变化。尽管有大量的尝试，以完全隔离机械应力从艺术作品，这是不可能完全实现在实践中。不能完全排除运输过程中艺术品的老化。因此，期望预先知道预期的损害，或者至少能够预先估计它。然而，就目前的研究状况而言，这只是不够可能的。因此，这个跨学科项目的目的是使人们有可能预测受到机械应力的纺织品基础的绘画损坏，并从客观的角度评估损坏。基本上，这需要两个步骤：首先，在运输之前必须确定油漆层的运动，其次，考虑到特定艺术品的纹理，必须能够推断出油漆层运动造成的损坏。第一个里程碑是使空间分布的油漆层运动可从机械注入（即帧运动）计算。数学模型和真实的对象行为之间的协议进行评估的基础上真实的运输和他们的准确再现在实验室中稳定的气候条件下。实验识别过程是为真实的绘画开发的，它允许对数学模型进行参数化和调整，但是，要注意对绘画的最小可能的压力。这样，可以预先确定已经完成的以及计划的运输的油漆层运动-建立油漆层运动估计器。这使得能够根据最小的油漆层运动动态地设计运输板条箱中的油漆安装。第二个里程碑是使用预测的油漆层运动来预测损坏量，并系统地将其与其他损坏源区分开来。为此，材料/分层和损伤所需的振幅/循环次数之间的关系在动态疲劳试验中通过实验确定，并在应力循环图中进行总结。损伤被光学捕获。这些测试是在本项目中特别制造的特殊形状的测试样本上进行的，或者是从艺术价值很小或没有艺术价值的绘画中获得的。为了估计真实的绘画上的损伤，使用循环计数方法和对数计数算法将绘画层的空间分布运动与应力循环图进行比较-建立损伤估计器。

Due to the increase in special exhibitions in the public and private sectors, the number of art transports has risen remarkably in recent years. Occasionally, that leads to obvious damage to the fragile objects, but most of all that leads to microscopically small changes as well. Despite extensive attempts to completely isolate mechanical stresses from pieces of art, that is impossible to achieve completely in practice. Aging of artwork during transport cannot be completely ruled out. It is therefore desirable to know the expected damage in advance, or at least to be able to estimate it beforehand. To the current state of research, however, this is only insufficiently possible. Therefore, the aim of this interdisciplinary project is to make it possible to predict damage to paintings with textile bases subject to mechanical stresses and to enable the assessment of damage from an objective perspective. Essentially, two steps are necessary for this: Firstly, the paint layer motion must be determinable before transport, and secondly, it must be possible to deduce the damage caused by the paint layer motion considering the texture of the particular artwork. The first milestone is making the spatially distributed paint layer movement calculable from the mechanical immission, i.e. the frame motion. The agreement between the mathematical model and the real object behavior is evaluated based on real transports and their accurate reproduction in the laboratory under stable climatic conditions. Experimental identification processes are developed for real paintings, which allow the mathematical models to be parameterized and tuned, however, with attention to the least possible stress on the paintings. This way, the paint layer motion for an already completed, as well as a planned transport can be determined in advance - a paint layer motion estimator is established. This enables to dynamically design painting mounts in transport crates in terms of minimal paint layer motion. The second milestone is to use the predicted paint layer motion in order to predict the amount of damage and to systematically distinguish it from other sources of damage. For this purpose, the relationship between materiality/layering and the amplitude/number of cycles required for damage is determined experimentally in dynamic fatigue tests and summarized in stress-cycle diagrams. The damage is captured optically. The tests take place on specially shaped test specimens that are particularly manufactured in this project or are obtained from paintings of little or no artistic value. In order to estimate the damage on real paintings the spatially distributed motion of the paint layer is compared to the stress-cycle diagram using cycle-counting methods and rainflow-counting algorithms - a damage estimator is established.