Polyimine is a type of covalent adaptable networks, known as vitrimer, endowed with dynamic imine bonds that can reversibly break and reform upon either heat or moisture. Its low topology freezing transition temperature (∼130 °C) and responsiveness to moisture make polyimine suitable for recycling, reprocessing, and repairing under mild processing conditions. Here, we demonstrate the rapid fabrication of carbon fiber-reinforced polyimine composites and their unique properties. Using a powder-based compression molding method, we are able to fabricate carbon fiber-reinforced polyimine within ∼4 min. The resulting composites exhibit similar mechanical properties as the samples prepared through much slower liquid-based impregnation method (>24 h). We also demonstrate in situ, mold-free repair of polyimine composites with a curved surface at low temperature and pressure (∼75 °C, implemented by a handheld iron for 5 min). The malleability, weldability, and full recyclability of polyimine composites fabricated by the powder-based method are also demonstrated. These unique properties offer great promise for expanding the manufacturing capability and extending the service life of fiber-reinforced composites.

A method to simulate the forging process and corresponding strain-induced austenitic-martensite phase transformation is formulated in the Eulerian description and its feasibility is examined. The method uses finite volume meshes for tracking material deformation and an automatically refined facet surface to accurately trace the free surface of the deforming material. By means of this finite volume method, an approach has been developed in the framework of metallo-thermo-mechanics to simulate metallic structure, temperature and stress/strain in the forging process associated with phase transformation. The incremental expression on the formulation of the kinetics equation is derived from Tsuta and Cortes' model. A mixture rule is adopted to evaluate the aggregate flow stress of the austenite-martensite affected by the respective flow stresses and phase transformation. This approach has been implemented in the commercial computer program MSC. SuperForge. This is the first report in which the fundamental fr amework is stated and the applicability of the developed method is confirmed using experimental results of the forging of a cylindrical billet. Some practical forging applications are demonstrated in the second report.

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Electric motors and generators produce vibrations and noise associated with many physical mechanisms. In this study, we look at the vibrations and noise produced by the transient electromagnetic forces on the stator of a permanent magnet motor. In the first stage, electromagnetic simulation is carried out to calculate the forces per tooth segment of the stator. The harmonic orders of the electromagnetic forces are then calculated using Fourier analysis, and forces are mapped to the mechanical harmonic analysis of the second stage. As a third stage, the vibrations of the structure are used to drive the boundary of acoustic domain to predict the noise. Finally, optimization studies are made over the complete system to improve the motor design and reduce noise. A simulation environment (ANSYS Workbench) is used to integrate a seamless workflow.

The Adaptive Multiple Euler Domains technology in MSC.Dytran has been extended for the Multi-material Euler Solver. This paper demonstrates the application of this new method to the dynamics of fuel tank filling. The interest in applicability of MSC.Dytran to fuel tank filling originated from a major car manufacturer. The model includes both the fuel and the air inside the tank. The simulation process starts with properly initializing the fuel and air inside the tank under gravity loading. The fuel filling process will then be demonstrated, including the venting of air through a venting tube. The simulation is performed with MSC.Dytran.