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了对能源和材料的需求不断增加。应用优化的蜂窝材料实现了更大的可持续性和成本节约。这促使了电化学沉积开孔聚氨酯(PU)泡沫塑料的涂层，以生产混合泡沫。电极定位过程中的材料传输限制导致了涂层的显著不均匀，到目前为止还没有得到充分的研究。在本项目中，对影响电沉积过程的参数进行了确定和优化。建立了描述多孔材料电沉积过程的宏观双面耦合材料模型，为进一步研究PU泡沫塑料的电沉积过程，研制了电化学渗流涂层电池，并在不同的参数设置下制备了复合泡沫塑料。一种基于重量测量、使用霍尔探头测量磁通密度和计算机断层成像图像的半破坏性确定混合泡沫涂层厚度的新方法正在开发中，该方法是一种时间和成本效益高的涂层厚度测量方法。参数速度、扩散常数、电场和沉陷常数对电沉积过程和由此产生的涂层厚度均匀性的影响将使用单侧耦合的宏观材料模型来表示。采用有限差分法实现了材料模型，并对电沉积过程进行了模拟。为了描述涂层厚度对电沉积过程的影响，研究了各几何性质之间的关系。这些相关性一方面是通过实验确定的，另一方面是由虚拟结构确定的。在模拟涂层厚度对电沉积过程的影响时，需要关联式。采用有限差分法实现了双侧耦合材料模型，并对电沉积过程进行了数值模拟。通过反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设置的优化混合泡沫塑料。最后，对优化后的泡沫塑料进行力学性能测试，研究涂层均匀性对材料性能的影响，通过这些步骤达到项目目标，从而实现均匀涂层厚度的Ni/PU杂化泡沫材料。均匀的涂层厚度使混合泡沫塑料具有均匀的材料性能，这使得它们具有作为能量吸收器或催化剂的多功能。

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.