Glulam bamboo has been preliminarily explored for use as a structural building material, and its stress–strain model under axial loading has a fundamental role in the analysis of bamboo components. To study the tension and compression behaviour of glulam bamboo, the bamboo scrimber and laminated bamboo as two kinds of typical glulam bamboo materials were tested under axial loading. Their mechanical behaviour and failure modes were investigated. The results showed that the bamboo scrimber and laminated bamboo have similar failure modes. For tensile failure, bamboo fibres were ruptured with sawtooth failure surfaces shown as brittle failure; for compression failure, the two modes of compression are buckling and compression shear failure. The stress–strain relationship curves of the bamboo scrimber and laminated bamboo are also similar. The tensile stress–strain curves showed a linear relationship, and the compressive stress–strain curves can be divided into three stages: elastic, elastoplastic and post-yield. Based on the test results, the stress–strain model was proposed for glulam bamboo, in which a linear equation was used to describe the tensile stress–strain relationship and the Richard–Abbott model was employed to model the compressive stress–strain relationship. A comparison with the experimental results shows that the predicted results are in good agreement with the experimental curves.

Corrosion to metal is a great challenge to major industries. Anticorrosive coatings can effectively prevent metal corrosion. In this study, we propose a novel method to prepare silica nanoparticles-covered graphene oxide (SiO2-GO) nanohybrids and anticorrosion SiO2-GO/waterborne polyurethane acrylic (WPUA) coatings. Firstly, we obtained silane-functionalized graphene oxide (A-GO) via a simple covalent functionalization of graphene oxide (GO) with 3-aminopropyltriethoxysilane. Secondly, SiO2-GO was synthesized by a simple sol–gel method with tetraethoxysilane in water–alcohol solution. Finally, the obtained SiO2-GO nanofillers were added into WPUA to prepare SiO2-GO/WPUA coatings. GO, A-GO, and SiO2-GO nanohybrids could be confirmed by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectra, and transmission electron microscope. SiO2-GO nanohybrids showed small size compared with the unfunctionalized GO. Meanwhile, GO, A-GO, and SiO2-GO nanofillers were added into WPUA. The electrochemical impedance spectroscopy and field emission scanning electron microscope indicate that SiO2-GO nanohybrids can be homogeneously dispersed in the WPUA coatings at 0.4% loading level and the SiO2-GO/WPUA film exhibits excellent anticorrosion performance. SiO2-GO nanoparticles can effectively utilize in the area of anticorrosive nanofiller industry. This study provides a convenient method of anticorrosive coating production.

A device for measuring the depth of the borehole base on the magnetic grid during orthopedic surgery is proposed in this article. It consists of a magnetic grid, winding sleeve, two Hall sensors, and control circuitry. The magnetic grid comprises permanent magnets and coil windings. The device fixes on the electric hand drill and works during the surgical operation. An axial pressure keeps the shaft end of the magnetic grid in contact with the surface of the bone or the plate steadily during the electric handheld drilling of the bone. The pressure is an electromagnetic force generated by the interaction between the permanent magnets and the coil windings. The force should be large enough to support the weight of the magnetic grid and a low fluctuation is maintained. The larger the device, the higher the electromagnetic force will be generated. The electromagnetic force is simulated and obtained with the software of Maxwell. The factors that influence the force were the permanent magnet, and the others are the length of permanent magnet and the turns on the coil. The results of orthogonal simulation show that the primary factor is the diameter of the permanent magnet. The optimized parameters include the following: the diameter of the magnet is 7 mm, length of each permanent magnet is 5 mm, and the turns on the coil are 80. Then the pressure force range is approximately 0.485–0.716 N, and the variance of the force is 0.137.

Structures made from natural fiber–polypropylene composite material usually have uniform mechanical properties throughout. In some applications, such as in products with snap-fit assembly, it is desirable to have lower stiffness in some parts of the structure while having significantly higher stiffness at other parts of the same structure. In this research, the effect of changing the material arrangement and composition in a cantilever beam made from functionally graded natural filler–recycled polypropylene (FGNF-RPP) composite on the deflection behavior was investigated under static mechanical loads. The composite material was made using 10%, 20%, 30%, and 40% waste wood sawdust as a filler and arranged in different sequences to fabricate beams having 30–40, 20–30–40, and 10–20–30–40 hybrid sections along the length. The deflection behavior was investigated by both experiment and finite element modeling. The results showed that the 30–40 setup produced the least deflection when the 40% end of the beam was fixed, while the 10–20–30–40 setup produced the highest stiffness when fixed at the 40% section. The study has shown that the FGNF-RPP structure can be custom-designed to obtain different stiffness along the same structure, thus making it possible to design products with varying stiffness.

Glass fiber-reinforced polymer (GFRP) composites are widely applied in automotive and shipbuilding industry. However, impact damage is unavoidable to the composites during production or service, and the evaluation of performance degradation after impact is necessary. The architecture of the fiber preform shows significant influence on the impact damage behavior of GFRP. The present work focused on the influence of preform structure on damage evolution and residual load-bearing capability of the composites. The microstructure and the residual strength after the impact of GFRP with plain-weave preform structure and cross-ply preform structure have been investigated, respectively. The low velocity impact primarily caused matrix cracking and delamination, but unobvious fiber failure to GFRP. More impact-damaged plies were detected in cross-ply composites than plain-weave composites after impact. It indicated that plain-weave preform structure owes better impact damage shielding capability. However, the GFRP with plain-weave preform structure exhibited better impact resistant ability under low impact energy but less residual strength under high impact energy, compared with the GFRP with cross-ply preform structure. The interaction between the warp and weft fibers made the plain-weave composites absorbing more energy in a single ply, which was the reason for the plain-weave composites to exhibit excellent damage shielding performance but poor residual strength under high impact energy.

In the automotive and aviation fields, the complex use environment is critical to the performance requirements of materials, the corrosion resistance of materials severely limits the service life of materials, and improving the corrosion resistance of materials is of great significance in industrial production. In this article, in situ synthesis of powder metallurgy was used to prepare Al-Zr-Ti composites, and the effects of the addition of different amounts of Ti elements on the microstructure and corrosion resistance of Al-Zr-Ti composites were studied. The results show that Ti atoms form Al3(Zr, Ti) compounds by substituting Zr atoms in Al3Zr in composite materials to form substituted solid solutions to improve the properties of composite materials. With the addition of Ti, the corrosion resistance of the composites is improved compared with Al-Zr binary; when the Ti content is 10% (wt), the corrosion resistance of the composites reaches the best value, the corrosion potential is −0.67211 V, and the corrosion current is 1.4804 × 10−7 A cm−2.

Nanodiamonds (NDs) have the characteristics of both diamonds and nanomaterials. However, it is difficult to disperse NDs, and this is why there is less research regarding NDs in the field of aluminum matrix composites. In the present work, NDs were modified via surface oxidation, and ND/Al matrix composites were successfully prepared via mechanical ball milling and vacuum sintering. The effects of different volume fraction of NDs (1%, 3%, 5%, 7%) after surface oxidation on the ND/Al matrix composite were analyzed using a metallographic microscope, scanning electron microscope, infrared spectrometer, X-ray diffractometer, microhardness tester, and universal testing machine. The results show that the optimal temperature of surface oxidation treatment is 673 K, which effectively purifies the surface of ND and introduces appropriate C=O functional groups. NDs are uniformly distributed in the aluminum matrix, and no harmful Al4C3 phase is formed. With an increase in the volume fraction of NDs, the grain size of the matrix first decreases and then increases, and the ultimate compressive strength first increases and then decreases. The volume fraction of ND with better comprehensive performance is 3% and the yield strength increased by 19%.

This article presents an analytical investigation on vibration characteristics of rotating graphene nanoplatelet (GPL)-reinforced plates subjected to rub-impact and thermal shock. The effective material properties are assumed to vary continuously and smoothly along the thickness direction of the plate and are determined via the Halpin–Tsai micromechanics model together with the rule of mixture. Considering the gyroscopic effect, the equations of motion are derived by adopting the Hamilton’s principle based on the Kirchhoff’s plate theory. Then, the Galerkin method and the small parameter perturbation method are utilized to obtain the free and forced vibration results for the rotating plate. A detailed parametric study is conducted to examine the effects of the GPL weight fraction, GPL distribution pattern, length-to-thickness ratio and length-to-width ratio of GPLs, and the rotating speed on free vibration characteristics of the nanocomposite plate. Attention is also given to the influences of the GPL weight fraction, thermal flow, and friction coefficient on forced vibration responses of the plate. The obtained results can play a role in the design of a rotating GPL-reinforced plate structure to achieve significantly improved mechanical performance.

Aluminum matrix composite materials being used in different sectors including automobile, aerospace, defense, and medical and are currently displacing unreinforced materials with their superior mechanical properties. The metal removal process of drilling is widely used in many structural applications. This study experimentally investigates the drilling characteristics of silicon carbide (SiCp)-reinforced Al 7075 composites produced by stir casting method. Also, two different drill materials with high-speed steel (HSS) and titanium nitride (TiN)-coated HSS carry out in drilling operation. The effect of operational parameters such as cutting speed and feed rate and materials parameters such as weight fraction of reinforcement and cutting tools on the surface roughness of drilled holes were evaluated in the drilling operations. The results of the drilling test indicate that the feed rate and cutting speed have a very strong effect on the surface roughness of matrix alloy and composite materials. The surface roughness ( Ra) values increased with increasing the feed rate and decreased with increasing the cutting speed. Under 0.10 mm/rev and 20 m/min drilling conditions and using HSS drill, surface roughness values for matrix, 5% SiC-, 10% SiC-, and 15% SiC-reinforced composites, were obtained 2.57, 2.59, 2.61, and 2.64 µm, respectively; besides, using TiN-coated HSS drill, surface roughness values were obtained 1.60, 1.63, 1.64, and 1.66 µm, respectively. An increase in the weight fraction of the abrasive SiC particle resulted in a very crucial deterioration quality of the drilled hole. TiN-coated HSS drills better performance exhibits than uncoated HSS drills for all the drilling operations about surface roughness properties. Short chip formations observed both the matrix alloy and the composite materials for two different drills in the drilling operations.

In order to further improve the mechanical properties of Ti-Al3Ti laminated composites, the endothermic semisolid reaction was used to fabricate Ti-Al3Ti-Al laminated composites, and the quasi-static compressive test, dynamic compressive test, and the ballistic penetration test were conducted on these composites. The results showed that the compressive strength and failure strain of Ti-Al3Ti-Al laminated composites prepared at 660°C are 1432 MPa and 35%, respectively. The dynamic response of these composites has obvious strain rate effect, and the crack grows in the shape of “Z.” The V50 of Ti-Al3Ti-Al targets is 509 m s−1. To sum up, Ti-Al3Ti-Al laminated composites have better mechanical properties and anti-penetration properties compared to Ti-Al3Ti laminated composites.