The tribological behavior of a thermoplastic polyurethanes (TPU) sliding against a non-polished steel counterface was studied as a function of load, velocity and temperature under dry conditions. Thermomechanical and chemical analyses were carried out on the TPU using DSC, FTIR and DMTA devices prior to the sliding tests. Contact changes were followed using a speed camera and an acoustic emission device. A simple thermal numerical simulation, to calculate temperature rise generated by friction, completes these analyses. To characterize wear performances, a wear rate was determined by considering the linear dependence between the wear volume and the product of the normal load by the travel distance (Archard model). Finally, wear mechanisms of TPU involve both abrasion scratches and adhesion patterns (Schallamach ridges). To conclude, a wear process description using the third body approach was proposed to gather the whole tribological results.

A novel experimental methodology is developed for the characterization of the vulcanization and foaming processes of an ethylene propylene diene (EPDM) cellular rubber and for establishing the relationship of its physical and mechanical property evolution with vulcanization and foaming process temperature. To establish this relationship, the vulcanization and foaming reaction kinetics and their coupling have been determined, as well as important parameters in the behavior of the material, such as conductivity, specific heat capacity and coefficients of expansion and foaming. This aforementioned strategy allows the setting of a material model that can be implemented into finite-element (FE) codes to reproduce the material changes during the vulcanization and foaming processes. The material model developed reproduces with enough accuracy the coupling of chemical kinetics of vulcanization and foaming reactions. The results provided by the numerical material model fit a similar trend, and values with an accuracy of 90–99% to those observed in the experiments conducted for the determination of the cellular rubber expansion in function of the temperature. Moreover, the cellular rubber expansion values agree with the structural analysis of vulcanized and foamed samples at different isothermal temperatures and with the proportional loss of mechanical properties in the function of the vulcanization and foaming degree.

Phone: þ34 976 01 1875, Fax: þ34 976 01 1888Composites of Mo 6 S 2 I 8 -nanowires, MoO (3 À x) -nanowires and MoS 2 -nanotubes with polyamide 6 (PA6) have been prepared in different concentrations up to 4% via melt-mixing using a laboratory twin screw extruder in order to investigate their tribological, mechanical and thermal properties. Chemical and structural composition of these nanowires and nanotubes with similar morphologies seem to play an important role in properties of fabricated polymer composites. Tribological tests were performed on the macroscale using a pin-on-disc (POD) tribometer and the thermal properties of the polymer nanocomposites were measured by differential scanning calorimetry to determine their glass transition temperatures and the levels of crystallinity. The behaviour of the nanowires (Mo 6 S 2 I 8 and MoO (3 À x) ) is different from the nanotubes (MoS 2 ) with respect to the induced effects on the friction coefficient and wear rate in function of concentration. The composites with the nanowires show a significant increase of the E-module of up to 38% at a nanowire concentration of 4 wt% in the glassy state of PA6, estimated from hardness measurements. The reduced friction coefficient and wear rates are related to the increased bulk shear strength of the nanowire polymer composites. In contrasts, nanotubes of MoS 2 did not show this strong reinforcement. The reduced friction coefficients and wear rates of the polymer composites with MoS 2 -nanotubes are predominantly related to the lubricating effect of the MoS 2 -nanotubes at the contact points.

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Industrial manufacturing management can benefit from the use of modeling. For a correct representation of the manufacturing process and the subsequent management, the models must incorporate the effect of the uncertainty propagation throughout the stages considered. In this paper, the proposed methodology for uncertainty management uses a nonintrusive method that is based on building a deterministic physics-informed real-time model for the a posteriori computation of output uncertainties. This model is built using tensor factorization as the Model Order Reduction technique. It includes as model parameters: material properties, process operations, and those random and epistemic uncertainties of known variables. The resulting model is used off-line to identify sensitivities and therefore to unify uncertainty management across the material transformation process. This method is presented by its direct application to an automotive door seal manufactured by continuous co-extrusion of several rubbers and reinforcement (metal strip and glass fiber thread).