Advances in Materials Science and Engineering

In this article, the influence of important parameters on the size-dependent thermoelastic behavior of functionally graded magneto-electro-thermo-elastic microcylinders (FGMEE) is studied by means of modified stress couple theory and under the influence of combined mechanical-thermal-magnetic loads. The equations of motion were derived by considering the linear behavior of the shells and considering the first-order theory of the nonlocal shear deformation of the shells. In the following, the results of solving the equations governing the buckle are analyzed. Based on this, firstly, the mechanical properties used in the shell are presented, then the linear buckling behavior is studied, and finally, the size-dependent buckling behavior of these structures is studied. In the presented results, the mode numbers of each buckling load are shown as n and m, where n and m represent the circumferential and longitudinal mode numbers, respectively. In the theory section, using the pairwise size-dependent theory, the stress is corrected, and considering the shell with a relatively thick geometric structure and the forces due to the heterogeneous thermal boundary conditions, a combination of convection heat transfer and displacement is used to obtain a three-dimensional shell temperature distribution. The equilibrium equations of the term electromagnetic coupling system are obtained using the first-order shear displacement field of the shell and the structural relationships in the functionally graded magneto-electro-thermo-elastic (FG-METE) intelligent material. Then, using appropriate analytical and numerical methods, various components of the displacement field, electrical and mechanical potential, and, most importantly, structural stresses for different boundary conditions are obtained.

SiC fiber-reinforced silicon matrix (SiC_f/SiC) composites are of significant interest for the aircraft engine. The thermal conductive behaviors of [0-90-0]s SiC_f/SiC composites along in-plane and out-of-plane (thickness) directions were reported in this paper. The thermal conductivity of the SiC_f/SiC composite was tested by using the steady-state measuring apparatus. Then, the thermal conductivity of the SiC matrix was predicted by finite element analysis (FEA). The representative volume element (RVE) models of SiC_f/SiC composites were built, and FEA was used to investigate thermal conductive behaviors. It was found that the thermal conductivity along the fiber radial direction was greater than it was in the axial direction in the SiC_f/SiC composite and that the thermal conductivity of the out-of-plane direction is lower than that of the in-plane one. The thermal conductivity of the SiC_f/SiC composite in the in-plane direction at room temperature was 31.1 Wm⁻¹K⁻¹ and 28.5 Wm⁻¹K⁻¹, and the thermal conductivity in the thickness direction was 24.9 Wm⁻¹K⁻¹. The experimental thermal conductivity showed a good agreement with the thermal conductivity of FEA.

The mechanical property of deep complex jointed rock mass is a hot topic in rock mechanics. In order to grasp the deformation and damage rules of through-going variable dip joint rock masses, the triaxial compression test and joint surface morphology scan test were conducted on cylindrical specimens in dry and wet conditions under 0, 5, 10, and 20 MPa water pressure. Through these tests, the deterioration law of rock samples under different pore water pressure in dry and wet conditions was studied. The effect of pore water pressure on the strength of saturated jointed rock sample is nonlinear. The imposed pore water pressure can significantly increase the axial deformation of rock samples, and higher pore water pressure can facilitate the deformation deterioration of samples. When the pore pressure is high, the rock samples show the characteristics of sliding shear failure. Under different pore pressure, the compressive strength of dry jointed rock is significantly higher than that of saturated jointed rock, and the saturated rock is more susceptible to sliding in the joint plane than dry rock. Dry jointed rock samples have stronger deformation ability than saturated jointed rock samples. The change rate of the morphologic parameters and the distribution of the failure cracks indicate that the stress concentration is evident in the middle of the joint plane.

Concrete is the most widely used material in civil engineering, but due to its inherent brittleness, the generation of cracks easily occurs. Crack healing is an effective method for restoring the mechanical properties of concrete and improving its durability. Of all the current concrete crack healing methods, microbial-induced calcium carbonate precipitation technology is an incredibly promising crack self-healing strategy that has received widespread attention in the field of concrete crack repair. As the biological self-healing agent has difficulty resisting the high alkali and high calcium environment in concrete, protection is required when it is used in concrete cracks.

Silica has shown numerous applications in different fields such as environmental, biomedical, agriculture, and even in chemical processing. However, due to high energy-intensive and cost-effective issues, researchers show interest to replace the conventional methods with biobased environmentally-friendly techniques for biosilica production from renewable biomass sources. Generally, silica is found to be available in amorphous and crystalline structures. For commercial purposes, silica is produced from alkyl orthosilicates ore that consists of polyethlydiorthosilicate, tetraethyl ortothosilicate, and tetramethyl orthosilicate. Another form of silica, silica gel, is produced from the selected resources of biomass, such as palm tree, wheat straw, maize leaves, teff straw, sugarcane bagasse, rice husk, rice straw, sugarcane leaf, oat husk, bamboo leaf, and corn cob. The production of biobased silica gel from agricultural residues is found to be a sustainable which receives a significant attention that can be replaced with inorganic-based silica gel for environmental concerns. Based on this context, there is a huge look for developing a process to produce biobased silica and silica gel from biomass resources with low energy utilization as promising alternatives to conventional methods. Keeping in view, current trends and methods for synthesis, the characterization of biobased silica and silica gel, as well as its wide prognostic applications were focused on a comprehensive review.

Fibre-reinforced polymers (FRPs) are composite materials of plastics reinforced with fibres. Cars, sea, aeronautics, and foundation projects progressively utilize fibre-reinforced polymers. This study aims to study the effect of adding multiwalled nanotubes fillers into the hybridized jute-glass FRP composites and their relative properties. This study uses multiwalled nanotubes (MWCNTs), and particles-hybrid jute-glass composites containing jute fibre chopped layer mats, woven glass mats, epoxy resin, and multiwalled nanotubes fillers were created using the hand layup method. After adding multiwalled nanotubes fillers in various weight proportions, the mechanical behaviours of fibre-reinforced polymers were analysed. The mechanical behaviours of laminated composites were tested using the ASTM standard; the following properties are tensile, flexural, and impact strength. The multiwalled nanotubes with 6% wt. attained the maximum mechanical properties compared to the 2 and 4 wt. % of MWCNTs. The E-based specimen contributes the most to the different types of specimens, with a contribution of 24.21% for tensile, 25.03% for flexural, and 24.56% for impact. The microstructures of hybrid composites were studied using a scanning electron microscope.