Development of a DIC-instrumented bubble inflation test: Characterization of ABS thermoforming.

This study addresses the mechanical characterization of ABS material under test conditions relevant to the vacuum-forming process. To examine the nonlinear response of the material behavior, a custom-made bubble inflation test setup was linked to a stereo Digital Image Correlation (DIC) system to measure the large deformation behavior during fast inflation of the material in the range of forming temperature (130 to 150°C). To attain the desired temperature, a temperature-control convection oven is employed. To assess the temperature uniformity of the material, an infrared (IR) camera is employed. The IR camera enables to assess the temperature distribution across the material surface. In order to replicate the strain and rate of deformation conditions experienced by the material in actual vacuum forming processes, DIC measurement was performed on a negative semi-sphere mold. By incorporating real-world strain data with a bubble inflation test setup, the experimental conditions closely mimic those encountered in vacuum-forming processes, leading to a more relevant evaluation of the material's behavior. The main output of this experimental work is to accurately measure the out-of-plane displacement of the material along the centerline during the isothermal inflation process. Subsequently, the collected data will be utilized to calibrate the nonlinear parameters of the material model using the inverse approach using Finite Element Model Updating (FEMU). This methodology ensures that the simulated bubble shape effectively matches the experimental observations at different temperatures during inflation. [ABSTRACT FROM AUTHOR]