## 3 Printing Information Model for Additive Manufacturing of Concrete Structures
### Verification of the Printing Information
#### 3.3.2 Competency Questions
``` SELECT?process WHERE{?wallpimo:hasProperty?property.?wallrdf:typepimo:AMWallComponent.?propertyrdf:typepimo:Density.?propertypimo:hasValue?denistyValue. FILTER(?denistyValue>=2050 &&?denistyValue<=2080)Based on the positive results of the competency questions on the PIM-O, the correctness of the PIM model is verified. Hence, the PIM model, representing a metamodel, can be instantiated into specific models that are used for designing and planning concrete printing jobs. In the following subsection, the PIM model is validated. ### Validation of the Printing Information Model

The validation aims to test if the PIM model is suitable to describe process, geometry, and material input parameters as well as interactions between the parameters in AM data modeling of concrete structures. The validation is conducted by implementing the PIM model into a software tool to collect, generate, and store the parameters necessary for AM of concrete structures. The UML diagram guides the development of the software tool, while the PIM-O provides the knowledge necessary for data integration and data storage. Building upon previous work of the authors [27], the software tool has been developed using the PIM model as the backbone, and it integrates BIM concepts into the concrete printing processes. As an illustrative example, a cylindric tank is planned for concrete printing using the software tool to generate toolpaths and gather inputs for simulating the build-up process. The software tool is written as a plug-in for BIM platforms for designing and planning concrete printing projects, and it generates specific models (i.e., instances) from the PIM model. The software tool, referred to as the \"PIM tool\", incorporates algorithms for (i) slicing, (ii) toolpath planning, and (iii) CNC code generation. The inputs of the PIM tool are user-defined parameters for process-related information (e.g., machine data, slicing data, and toolpath data) and material-related information (e.g., material specifications and material properties), which extend the BIM models. The PIM tool updates the BIM models as the slicing and toolpath planning are executed and outputs CNC code as machine instructions for concrete printers. For the exemplary case, the software tool facilitates the generation of information necessary for simulating the build-up process of the cylindric tank, in particular the temporal behavior of early-age concrete in accordance with the user-defined process parameters (printing speed and layer interval time), as shown in Figure 8. The information is tabulated and stored as a file, facilitating its interoperability with finite element analysis (FEA) software tools. The information is fed to a finite element model, and the build-up process is \begin{table}
\begin{tabular}{l l l} \hline \hline \multicolumn{1}{c}{**Competency Question**} & \multicolumn{1}{c}{**Answer**} & \multicolumn{1}{c}{**Result**} \\ \hline  & _AMWallComponent_ & \\  & _AMBeamComponent_ & \\  & _AMColumnComponent_ & ✓ \\  & _AMSupportComponent_ & \\  & _AMReinfComponent_ & \\ \hline CQ2: Identify walls that are designed using concrete as main material & Instance: _wall\_LOG_ & ✓ \\ \hline CQ3: Identify AM processes that have walls as output & Instance: _cp\_Process1_ & ✓ \\ \hline CQ4: Retrieve walls that have a bulk density between 2050 and 2080 kg/m\({}^{3}\) & Instance: _wall\_LOG_ & ✓ \\ \hline CQ5: Which fresh state material property are identified by material test data? & Instance: _property\_GreenStrength_ & ✓ \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of the competency question query results for PIM-O. simulated. The results of the simulation are compared with those reported in the literature to evaluate the completeness of the inputs. The cylindrical tank is prepared for simulating the concrete printing process based on a BIM model, as shown in Figure 9. The cylindrical tank is designed with an inner radius of 250 mm, a thickness of 60 mm, and a height of 600 mm.