This study investigates the forced vibration analysis of a sandwich panel on a Winkler-Pasternak foundation, incorporating magneto-rheological (MR) fluid. Displacement and strain stress relations are derived through Hamilton's principle, considering high-shear deformation and modified coupled stress. The resulting equations of motion are then formulated, and the vibration equations are obtained using the Galerkin method. To validate the accuracy of the finite element formulation, a careful assessment is conducted by comparing it with results obtained from assumed modal formulations and data available in existing literature. This comprehensive examination also involves the use of various materials to evaluate the influence of the MR core. The outcomes of the study indicate that the thickness of the MR core has a significant impact on damping, whereas the piezoelectric layer has a lesser effect. In particular, PZT-7A emerges as the piezoelectric material with the most prominent effect on damping vibration forces. Additionally, the study considers the effect of nanoparticles.
We examine the impact of adding zinc oxide (ZnO) nanorods to an aluminum (Al)-based composite. The composite material was meticulously produced employing cold compaction and microwave hybrid sintering. This study examined Al-ZnO chemical interactions and compositional changes using cutting-edge methods including simultaneous thermal analysis and Raman spectroscopy. The addition of 2 wt.% ZnO to pure Al increased hardness by 28% and compressive strength by 19%. Our investigation showed that 2 wt.% ZnO reinforcement reduced material wear by 47%. We discovered the depth of wear and the various factors that affect it by microscopic inspection of worn surfaces.
Delamination prevents the structure from performing efficiently because it causes significant variations in the dynamic response. Vibration-based nondestructive testing methods are applied to fiber metal laminate beams for possible delamination detection. The impact of delamination on a 2/3 configuration aluminum and mild steel-based fiber metal laminates was investigated, and for this, artificial delamination was introduced in the beam. By free vibration analysis, the effect of delamination on the beam stiffness is investigated. In this study, to provide strong validation, the stiffness of each delaminated specimen is computed by the vibration method and the deflection method. The stiffness results obtained for delaminated specimens of aluminum and mild steel fiber metal laminate for the same configuration are compared with each other, and it is found that the results of the stiffness are comparatively higher for mild steel fiber metal laminate (FML) than aluminum FML. According to the to the vibration study, the aluminum FML is sensitive to the change in delamination geometry. Therefore, regardless of the delamination area, it is evident that the free vibration-based delamination detection method can accurately predict the location and depth of the delamination in any fiber metal laminate. Finally, it is also discovered that the stiffness of the beam reduces as the delaminated area increases along with changing position.
The performance of a material can be significantly damaged by oxidation, corrosion, and thermal stress degradation carried on through high temperatures. Coatings are one of the important developments to improve the performance of materials exposed to high-temperature working conditions. This study evaluates the critical purpose of plasma spray coatings in safeguarding and enhancing high-temperature components across a range of industries, such as manufacturing, aerospace, and energy. This paper shows how these coatings can improve the longevity of critical components, highlighting the importance, current challenges, and latest developments in research regarding plasma spray coatings in modern high-temperature applications. In the end, this study has consequences for future advancements in the field and authenticates the vital role that plasma spray coatings play in improving material performance in high-temperature environments.
The mechanical properties of grid composite sandwich panels reinforced with natural cotton fibers with square and rhomboid-shaped cores (ribs) were studied. The sandwich panels were made of natural cotton fibers and polyester resin and produced using the hand lay-up method. The ribs, made in three types with six, eight, and ten layers (number of cotton natural fibers), and skins, made in four layers, were vital elements in our investigation. We explored the effect of ribs' thickness (number of fiber layers) and core shape on the mechanical behavior of sandwich panels. Panels were then subjected to a three-point bending test, a widely accepted method for evaluating materials' flexural strength and stiffness. The resulting load-displacement curves provide valuable information about the material's behavior under load. In addition, bending stiffness, flexural strength, core ultimate shear strength, facing ultimate bending strength, and energy absorption values were calculated for each sandwich panel. Also, the panels were numerically simulated in Abaqus, a highly reliable software known for its accuracy, and the numerical results were compared with the experiment. The results further validated the accuracy of our methods. The results, which demonstrated the square core's superiority in bending stiffness, flexural strength, and energy absorption, have profound implications for the design and development of advanced composite materials in the field of materials science and engineering.
In present study, treated Saccharum munja fibers considered as reinforcement material in particulate (PC), short and random (SRC) and in unidirectional (UDC) form along with AW106 epoxy resin and HV953 hardener as matrix material. Composite laminates were fabricated using a compression molding machine. Surface treatment of fibers to remove the dust, lignin, and hemicellulose caused better mechanical and free vibration properties. Tensile and flexural tests show the highest values of strength to be 170 MPa and 143 MPa, respectively, in the case of UDC composite, while the lowest values were seen in the case of PC. Addition of munja fiber in epoxy matrix enhances the fiber matrix adhesion bonding. The PC composite shows better value of damping than SRC and UDC composites. The highest natural frequencies (43, 233, 298, 849, 918, and 1440 Hz) were obtained in the case of UDC irrespective of all modes. The highest water absorption rate was obtained for the SRC, while lowest value was found for 15/15. Due to the surface treatment of Saccharum munja, water absorption properties were also improved. The best conclusion from the collected results for the thermogravimetric analysis was the creation of neat resin (NR) for the treated short and random Saccharum munja fiber polymer composite. ANOVA analysis shows that the experimental results output in of tensile and flexural tests are significant.
