부산대학교 도서관

The Rheometrics variable-speed impact tester (RVSIT) was evaluated with regard to the stability and reproducibility of the velocity and load signals. A drop in the speed of the probe was observed upon impact. The extent of the drop depends on the impact speed and the material tested. Mounting the load cell ahead of the impact rod was found to improve the reproducibility of load-deflection signals and to alleviate spurious postpuncture noise. A new rod was designed to apply circumferential loads on notched specimens. Load-deflection data obtained with this type of loading were used to calculate the dynamic critical stress intensity factors (SIF) for sheet molding compound (SMC) and reinforced reaction injection-molded (RRIM) polyurethane panels in the opening and the sliding modes.