Modelling of electrical contact resistances at metal plastic interfaces

使用导电改性塑料的一个重要方面是它们的接触。除了随后进行接触的方法（例如，特别是注塑成型，但也可以想到其他常见的初级成型、转换和连接方法的集成。所有这些接触可能性导致界面中的特定状态，其可以通过局部变量（例如，填料位置、结晶度等）。本研究计画的想法是以这些局部变数为基础，对接触电阻进行模型描述。在随后的步骤中，该描述性模型将用作定量预测界面阻力的基础。为此，生成局部变量的特定状态，并测量接触电阻。这取决于对局部变量的精确调节以及对接触电阻的可再现且精确的测量。对于接触电阻的测量，开发并使用了经典的测量方法，结合模拟方法和额外的界面直接物理测量。局部变量的不同状态只能通过可调变量间接调节，例如注塑过程中的气缸温度。因此，需要子模型来描述间接调整的局部变量和直接可调整的过程变量之间的关系。为了验证量化模型及其预测的意义，最终生成不同的应用典型接触场景，并将所得接触电阻与模型值进行比较。通过处理用于FEM应用的模型方程，可以结合现有的模拟方法（如注塑模拟或电气模拟）来实现建模。

An important aspect for the use of electrically conductive modified plastics is their contacting.In addition to methods which subsequently make contact (e.g., pinch or fuse contacts), there are also numerous process-integrated methods.Especially injection molding, but also the integration of other common primary forming, transforming and joining methods is conceivable. All these contacting possibilities lead to a specific state in the interface which can be described by local variables (e.g., filler position, crystallinity, etc.).The idea of the research project is to make a model description of the electrical contact resistance based on these local variables. In a subsequent step, this descriptive model will be used as the basis for a quantitative prediction of the interfacial resistance. For this purpose, specific states of the local variables are generated, and the contact resistance is measured. This depends on a precise adjustment of the local variables and on a reproducible and accurate measurement of the contact resistance. For the measurement of the contact resistance, classical measuring methods in combination with simulative approaches and additionally direct physical measurements at the interface are developed and used.Different states of the local variables can only be adjusted indirectly via adjustable variables as for example, the cylinder temperature during injection molding. Accordingly, submodels are required to describe the relationship between indirectly adjusted local variables and directly adjustable process variables. To validate the significance of the quantified model and its predictions, different application-typical contacting scenarios are finally generated, and the resulting contact resistances are compared with the model values. By processing the model equations for FEM applications, the possibility is created to implement the modeling in combination with existing simulation methods such as injection molding simulations or electrical simulations.