## 1 Introduction  
Function modeling enables engineers in product development to synthesize, elaborate, concretize, evaluate, communicate and discuss technical problems and solutions, and even to explore and understand potential failure mechanisms in complex systems [1]. The functional domain links the requirements for technical systems to possible solution concepts and is therefore of paramount importance for digital product development processes. Current investigations show that system architectures created from the functional domain are nearly identical to the architecture of real systems [2]. In the field of digital function modeling, generic libraries for functions were developed [3] and were formulated as object-oriented models using the well-known Systems Modeling Language (SysML) [4]. The central advantages of this formulation are, on the one hand, the improvement of model consistency and traceability and, on the other hand, the integration of simulation processes in order to provide the possibility of an early evaluation of concept variants [4]. In spite of these advantages, the integration of the functional domain into current digital product development processes in industry has not been addressed sufficiently yet. This paper investigates the possibility of using GBDLs for this endeavor. One major advantage of this integration is the opportunity of automated analyses in this domain, such as fault tree analyses (FTA--compare Riestenpatt gen. Richter and Rudolph [5]) and fault propagation path analyses, which could facilitate the estimation, planning and management of engineering change significantly [6]. Essentially, the determination of a suitable solution to a design problem can be understood as an ongoing interplay between reasoning about what is required and what particular combination of possible solution elements will be able to provide for this, and how [7; 8]. Determining a suitable solution is, consequently, an iterative process that consists of phases with a main emphasis on analyzing, and phases with a main emphasis on gradually synthesizing the potential solution(s). It is important to note that some features or constraints of the solution(s) may require a redefinition of the problem, either partial or complete [9]. These kinds of iterations are not limited to specific design stages, but can be present through large process segments or even the entire design process. This kind of iteration needs to be connected with a continuous update of the product and process models that represent the concerned information [10]. In order to support this endeavor, several models and processes were proposed over the last several years; these models and processes specifically aim to coherently model functions and solutions. The models aim to create links between the conceptual and the subsequent design stages (i.e., they aim to bridge the gap between qualitative information on an abstract level and increasingly quantitative information on more concrete levels) in a traceable manner. These models and processes include the System Modeling Language (SysML), the Object-Process Methodology (OPM, [11]), Function Analysis Diagrams [12], Computational Functional Basis [13; 14; 15; 16], and the Integrated Function Modeling (IFM) Framework [17]. The application of such models was investigated by several research teams [18; 19; 20]. In general, these models and processes still remain at an abstract level for the description of the resulting technical system. It is important to note that these models and processes primarily focus on the product structure and that they describe its sub-systems, parts and their functional or physical links on an abstract level. It is highly desirable to transfer this information into simulation tools that are used for system evaluation and verification.