Narrow Results

The embedded atom method (EAM) is used to construct an interatomic potential for modelling interfaces in Cu–Nb nanocomposites. Implementation of the Ziegler–Biersack–Littmark (ZBL) model for short-range interatomic interactions enables studies of response to ion bombardment. Collision cascades are modelled in fcc Cu, bcc Nb, and in Cu–Nb layered composites in the experimentally-observed Kurdjumov–Sachs (KS) orientation relation. The interfaces in these composites reduce the number of vacancies and interstitials created per keV of the primary knock-on atom (PKA) by 50–70% compared to fcc Cu or bcc Nb.

Natural fibers are extracted from natural resources such as stems of plants. In contrast to synthetic fibers (e.g., carbon fibers), natural fibers are from renewable resources and are eco-friendlier. Plant fibers are important members of natural fibers. Review papers discussing the microstructures, performances and applications of natural plant fiber composites are available in the literature. However, there are relatively fewer review reports focusing on the modeling of the mechanical properties of plant fiber composites. The microstructures and mechanical behavior of plant fiber composites are briefly introduced by highlighting their characteristics that need to be considered prior to modeling. Numerical works that have already been carried out are discussed and summarized. Unlike synthetic fibers, natural plant fiber composites have not received sufficient attention in terms of numerical simulations. Existing technical challenges in this subject are summarized to provide potential opportunities for future research.

An attempt has been made to investigate steady state creep behavior of thermally graded isotropic discs rotating at elevated temperatures. For this purpose, composite discs of aluminum matrix reinforced with silicon carbide particulate have been taken. Modeling of stress and strain rate distributions for discs operating under linear thermal gradient has been done using von Mises’ yield criterion and threshold stress-based creep law. Similarly modeling has been done for discs operating under non-linear thermal gradient. The results are compared with the disc having a uniform temperature profile from inner to outer radius and are displayed graphically in designer friendly format for the said temperature profiles. A small variation is observed for radial and tangential stresses for the said thermal gradations. However, the strain rates vary significantly in the presence of thermal gradations as compared to a disc having uniform temperature throughout the radial distance. Thus, it is observed that there is a need to extend the domain of thermal gradation for designing rotating discs.

This study reports the optimal frequencies and damping factor of the honeycomb sandwich composite plates. The sandwich panel face sheets have been considered as layered composite and honeycomb core. The higher-order shear deformation theory has been adopted to formulate the structural model and solve the governing equations of motion of sandwich structures to compute the frequencies. An optimal layout of the honeycomb composite laminated sandwich structure is being utilized to improvise both the fundamental natural frequencies and damping factors using a teaching–learning-centered artificial bee colony (TLABC). An experimental investigation is performed to demonstrate the effectiveness of the current TLABC algorithm to identify the optimal values by comparing them with numerically obtained results. Additionally, for the optimal layer sequences and the fiber orientations of the composite laminated plates, several optimization problems are developed with the objective functions of frequency maximization and modal damping factors (MDF). The TLABC algorithm integrated with finite element method has been utilized to evaluate the said responses. Hence, it is concluded that the efficient design layout of a honeycomb sandwich composite plate configurations would provide the guidelines for the designer to control the vibration effectively.

The majority of ultrasonic characterizations are done on thermoplastics, with just a few articles available on the characterization of thermoset resin characteristics. A non-destructive methodology for monitoring fatigue and static deformation induced by mechanical loading on a fiber-reinforced plastic is presented. However, these materials’ dynamics of elastic waves are considerably more complicated. A large part was devoted to the calculation of dispersion curves of guided waves in composites. Therefore, this study presents a thorough description of the Glass/Epoxy system by comparing ultrasonic and mechanical data. Ultrasonic wave propagation at high frequencies, functioning as a dynamic mechanical deformation, may be utilized to calculate longitudinal and shear moduli during static and dynamic loading. The evolution of attenuation and velocity during loading is linked to the significant changes that occur during the aging process. The experimental transfer function is determined by the Fourier transform of all the obtained ultrasonic echoes.