Development of a two-sided coupled material model for the characterization of ideal process parameters of application-optimized foams

世界人口的增长和日益繁荣导致对能源和材料的需求不断增加。应用优化蜂窝材料实现更大的可持续性和成本节约。这促使开孔聚氨酯（PU）泡沫通过电化学沉积涂层生产混合泡沫。在电极定位过程中的材料传输限制导致显著的涂层不均匀性，迄今尚未得到充分的研究。本课题对电沉积工艺的影响参数进行确定和优化。目的是建立一个宏观的双面耦合材料模型来描述多孔材料的电沉积过程。为了进一步发展聚氨酯泡沫上的电沉积，研制了一种电化学流动镀膜池，并利用不同的参数集制备了混合泡沫。基于重力测量、霍尔探头磁通密度测量和计算机断层扫描图像，开发了一种半破坏性测定混合泡沫涂层厚度的新方法，为测量涂层厚度提供了一种既省时又经济的方法。采用单侧耦合宏观材料模型，阐述了速度、扩散常数、电场和沉降常数等参数对电沉积过程和镀层厚度均匀性的影响。采用差分法实现了材料模型，并对电沉积过程进行了模拟。为了描述镀层厚度对电沉积过程的影响，研究了镀层几何性能之间的关系。这些相关性一方面是由实验确定的，另一方面是由虚拟结构确定的。为了模拟镀层厚度对电沉积过程的影响，需要关系式。利用有限差分法建立了双面耦合材料模型，并对电沉积过程进行了模拟。通过反计算确定了电沉积工艺的最佳工艺参数。这些工艺参数被用于生产具有最佳参数集的优化混合泡沫。最后，对优化后的泡沫进行力学试验，研究涂层均匀性对材料性能的影响。通过这些步骤，将达到项目目标，从而实现Ni/PU混合泡沫的均匀涂层厚度。均匀的涂层厚度使混合泡沫具有均匀的材料特性，这使它们具有作为能量吸收剂或催化剂的多功能。

The growing world population and increasing prosperity lead to an increasing demand for energy and materials. Application-optimized cellular materials achieve greater sustainability and cost savings. This motivates the coating of open-pore polyurethane (PU) foams by electrochemical deposition for the production of hybrid foams. Material transport limitations during the electrode positioning process cause significant coating inhomogeneities that have not been adequately investigated so far. In this project, the influencing parameters on the electrodeposition process are to be determined and optimized. The aim is to develop a macroscopic two-side coupled material model to describe the electrodeposition process on porous materials.For the further development of the electrodeposition on PU foams, an electrochemical flow-through coating cell is developed and hybrid foams are produced with the aid of different parameter sets. A new method for the semi-destructive determination of the coating thickness of hybrid foams based on gravimetric measurements, measurements of the magnetic flux density using a Hall probe and computer tomography images is being developed for a time and cost effective method of measuring the coating thickness. The influence of the parameters velocity, diffusion constant, electric field and sink constant on the electrodeposition process and on the resulting coating thickness homogeneity will be formulated using a one-sided coupled macroscopic material model. The material model is implemented by finiter differences and the electrodeposition process is simulated. To describe the influence of the coating thickness on the electrodeposition process, the relationships of the geometric properties are investigated. These correlations are determined experimentally on the one hand and by virtual structures on the other hand. The correlations are required for modelling the influence of the coating thickness on the electrodeposition process. The two-side coupled material model is also implemented using finite differences and the electrodeposition process is simulated. Optimum process parameters of the electrodeposition process are determined by inverse calculation. These process parameters are used for the production of optimized hybrid foams with exactly this optimal parameter set. Finally, mechanical tests will be carried out on the optimized foams to investigate the influence of coating homogeneity on the material properties.Through these steps the project goal and thus a homogeneous coating thickness of Ni/PU hybrid foams shall be achieved. A homogeneous coating thickness gives the hybrid foams homogeneous material properties, which makes them multifunctional as energy absorbers or catalysts.