| Abstract [eng] |
With the rapid expansion of manufacturing technologies, there is a growing demand for composite materials that are not only mechanically strong but also possess additional functional properties such as electrical conductivity, flexibility and formability. One such direction is the development of graphene-reinforced TPC, intended for 3D printing and subsequent robotic incremental forming. The main objective of this study was to evaluate the behavior of TPC material enhanced with graphene (from 4% to 8%) under deformation, assess its mechanical properties, and determine suitable forming parameters. During experimental investigations, tensile (ISO 527-3), electrical conductivity (ISO 3915), and cupping (ISO 20482) tests were performed to evaluate the properties of TPC/Gr composites with different graphene concentrations. The tensile test results showed that increasing the graphene content up to 8% significantly improved tensile strength and shear modulus, while reducing the strain at break, indicating decreased elasticity. Electrical conductivity tests revealed that higher graphene content improved conductivity – the lowest resistance values were recorded for the TPC/Gr-8% [-45°/45°] structure. However, the TPC/Gr-5% [-45°/45°] structure was selected as the optimal composition due to its stable conductivity under deformation and well-balanced mechanical performance. Cupping test results indicated that increasing graphene content enhanced mechanical resistance, but reduced the material’s ability to deform without failure. The pure TPC sample (without fillers) demonstrated the greatest indentation depth, while the TPC/Gr-8% [-45°/45°] structure showed the least. The TPC/Gr-5% [-45°/45°] structure ranked in between, showing sufficient resistance and deformation capability, thus being considered the most suitable for further forming experiments. In robotic incremental sheet forming trials, the TPC/Gr-5% [-45°/45°] structure was subjected to different temperatures to identify optimal processing conditions. The results showed that at 270-280 °C, deformation was uniform, the surface remained intact and the forming process was stable and free from structural defects. In contrast, at lower temperatures (240-250 °C), microcracks and surface imperfections were observed, which reduced structural integrity and reliability. Numerical analysis using the finite element method was conducted to assess the behavior of the TPC/Gr-5% [-45°/45°] structure during cupping and robotic incremental sheet forming forming. After updating the material model parameters based on experimental data, the computed load and deformation values closely matched those obtained experimentally: the stress and indentation depth from cupping differed by less than 2%, and the forming force deviation did not exceed 8%. These findings confirm the numerical model’s suitability for predicting real-world forming processes and its applicability for further process optimization. |
