In this paper, we propose a new FE model of a carbon fiber reinforced thermoplastic (CFRTP) in order to capture the deformation during a thermoforming process because the thermoforming process of CFRTP has increased its presence in the automotive industry for its wide applicability to the mass production car. The proposed model can describe temperature dependent non-linear bending property of CFRTP by a set of elements which consists of two shell elements with membrane elements in between them. The membrane elements represent temperature dependent anisotropic in-plane behavior by calculating stress contributions of the textile reinforcement and thermoplastic in a parallel system. By applying Reuss model to the stress calculation of thermoplastic, the in-plane shear behavior which is the key deformation mode during forming can be accurately predicted. FE model is constructed based on the results of three point bending and bias-extension experiments which are conducted in the range of the process temperature. Thermoforming simulations are presented and compared to experimental results. Simulated outline and shear angle are in good agreement with experimental results. It will be shown by sensitivity study that the effect of the temperature plays an important role in deformation during a non-isothermal forming process.

Burn marks are serious defects in injection-molded parts that can result in many defective products. There is thus a great demand for effective systems to reduce these defects in injection-molded products. In this study, we investigate the relationship between gas generation and molding conditions using gas sensors. The results show that gas sensors can be used to monitor burn marks.

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A Herbert pendulum was modified to a lightweight pendulum with a cylindrical indenter by Habara in order to measure the hardness of viscoelastic materials such as plastics and rubbers. It is difficult to provide enough strain to evaluate the hardness of hard materials using the Herbert pendulum with a cylindrical indenter because the contact stress between the indenter and the specimen is smaller than that of the original Herbert pendulum. In this study, a modified measurement system is developed to accurately measure the swing angle of a lightweight Herbert pendulum with a cylindrical indenter. Two independent laser displacement meters are installed, to provide a noncontact measurement of the swing angle. The modified Herbert pendulum with a cylindrical indenter is evaluated for measuring the hardness of metals. Four types of Herbert hardness are compared with the Vickers hardness. Good correlation is shown between the damping hardness (one type of Herbert hardness) and the Vickers hardness. The damping hardness measured based on the modified Herbert hardness tester can be used as the hardness parameter of the metals.

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