Thermomechanical Simulation of Infrared Heating Diaphragm Forming Process for Thermoplastic Parts

International audienceAn innovative methodology for the thermomechanical simulation of the infrared heating diaphragm forming (DF) process is proposed. In the first section of the paper, the heat transfer mechanisms between the infrared (IR) heating lamps and the thermoplastic plate are simulated, and the effect of the various preheating parameters on the heating time and temperature distribution is investigated. In the second section, the mechanical deformation of the thermoplastic component is simulated to enable prediction of heat losses due to the plate contact with the mold. Based on the developed simulation methodology, the main process parameters — e.g., the number, location, and power of IR lamps for optimal preheating; the heat losses during plate deformation; and the minimum required mold temperature throughout the forming phase — are derived for five different thicknesses. The optimization results show that the forming parameters considered influence the heating of the plate in a complex and interactive way; in addition, it is found that with increasing plate thickness, the heating time required to reach the desired temperature also increases

A critical assessment of multifunctional polymers with regard to their potential use in structural applications

Multi Wall Carbon Nanotubes (MWCNTs) and Polyhedral Oligomeric Silsesquioxanes (POSS) are common additives to simultaneously enhance electrical conductivity and flame resistance. In the present work, the synergistic effect of the addition of MWCNTs and two different POSS compounds, DodecaPhenyl POSS (DPHPOSS) and Glycidyl POSS (GPOSS), on the mechanical behavior of multifunctional polymers subjected both to quasi-static as well as to fatigue loading was investigated. The results of the mechanical tests were discussed supported by Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) analyses. The results showed that the incorporation of MWCNTs in the resin containing GPOSS determines a slight decrease in the flexural modulus compared to the unfilled resin. The material filled with MWCNTs and DPHPOSS shows a higher reduction of the flexural modulus as compared to the other analyzed materials. The same trend was observed also for the flexural strength; more than 50% decrease of the flexural strength of the material filled with MWCNTs and DPHPOSS is detected. As far as the fatigue is concerned, it seems that the incorporation of the flame retardants led to an appreciable decrease in the fatigue life. The decrease in the mechanical properties of the nanofilled resin loaded with DPHPOSS is most likely due to the presence of aggregates of DPHPOSS crystals in the matrix. This hypothesis is confirmed by EDX analysis which shows that DPHPOSS forms some small aggregates, whereas GPOSS, being molecularly solubilized in the epoxy formulation, shows mechanical performance more similar to the sample loaded only with carbon nanotubes