Advances in Mechanical Engineering

Valerga Puerta, Ana P; Fernandez-Sanz, Gema; Bañon, Fermin; Fernandez-Vidal, Severo R

doi: 10.1177/16878132231201297pmid: N/A

The durability and degradation of polymers is very important for product design in terms of material choice. The degradation behavior of two biodegradable thermoplastic materials manufactured by 3D printing, Enviro ABS and PLA, was studied. The action of the sun and seawater was simulated to find out how they affect the properties of these materials over a period of 8 weeks. The yield strength, maximum elongation, ultimate tensile strength, and microscopy were analyzed, as well as dimensions and mass changes. These biodegradable materials were studied to conclude whether there is an environmentally friendly alternative to traditional ABS, being one of the most widely used petroleum-based plastics in industry and in fused deposition modeling (FDM) or fused filament fabrication (FFF). PLA showed a weight loss and increase in ultimate tensile stress on degradation by sunlight and a prolonged decrease in ultimate tensile stress on degradation by seawater due to humidity absorption. In contrast, Enviro ABS does not show a noticeable difference between the beginning and the end of the test, which leads to the conclusion that Enviro ABS is a good alternative to conventional ABS without forgetting the environmental effects that are currently involved in the manufacture, recycling and composting of this type of material.

Li, Shusen; Zhang, Yan

doi: 10.1177/16878132231200410pmid: N/A

In this work, a protective structure with 2A12T4 aluminum alloy as the panel material and plywood as the core layer was designed. Penetration experiments were performed by firing multiple projectiles from a light gas gun. The impact behavior, damage mode, absorbed energy, and residual strength of the interlayer after impact were studied. The dynamic response and the failure of the interlayer were analyzed. Disbonding, fiber fracture, buckling, shear, and core fracture between the metal layer and the composite layer of the front panel were observed. The impact resistance of the sandwich plate was also studied. Based on the results of the experiments and numerical simulations, failure determination of the plywood core layer was achieved using the Hashin criterion, and a finite element model was established using ABAQUS software. High-speed impact testing was performed with a Hopkinson pressure bar. The stress–strain relationship under a high dynamic strain rate is given here, and the energy absorption efficiency under loading in different directions was analyzed. Finite element analysis of the representative volume elements in the wood microstructure was also carried out. The results reported here can be used to guide optimal design of sandwich structures suitable for use under high-speed impact conditions.

Che, Lida; Wang, Peng; Ma, Liliang; Feng, Yuqi; Zhao, Jie; Li, Xiangyang

doi: 10.1177/16878132231209640pmid: N/A

Pre-stressed steel wire-wound ultra-high-pressure vessels (PSWUPV) are commonly used in engineering to transport ultra-high-pressure media. However, the complex structure of these containers and the frequent pressure changes pose challenges in designing their structural and fatigue strength. Three simulation design methods were compared and analyzed: the two-dimensional force method, the two-dimensional cooling method, and the three-dimensional force method. The results showed that all three methods met the stress analysis requirements. The three-dimensional surface mass force method was chosen as the preferred method for engineering applications, specifically for the process of steel wire-winding loaded with mass force. The combined load case method was used to examine the influence of steel wires on the stress of the thick-walled cylinder when wound layer-by-layer. The study also focused on the changes in stress relaxation within the steel wire layer. The results demonstrated that the residual stresses of the core cylinder and the winding layer exhibited quasi-linear superposition during the winding and preloading process. The preloading effect of the steel wire weakened with increasing friction coefficient. Simulation results showed larger errors with excessively large or small normal stiffness coefficients. Based on theoretical solutions and verification studies, the optimal friction and normal stiffness coefficients were determined to be 0.02 and 1, respectively. By achieving a reasonable distribution of residual stress in the thick-walled cylinder of the ultra-high-pressure vessel through fatigue analysis, the fatigue life of the cylinder was significantly improved.

Li, Rujie; Zhong, Peixuan; Zhang, Yalong; Pang, Xueqin

doi: 10.1177/16878132231207823pmid: N/A

Difficult-to-machine materials such as stainless steel are widely used in the construction industry, because of their excellent mechanical properties and corrosion resistance. However, the poor tool-chip contact environment, severe tool wear, and heavy chip accumulation inhibit the machining efficiency. In this paper, 316L austenitic stainless steel was selected to investigate the effect of a variable-length restricted contact tool (VL-RCT), aiming at reducing the cutting temperature and increasing the tool life. A finite element simulation model of restricted contact cutting was established to investigate the machining parameters and restricted contact parameters on cutting performances and to clarify the mechanism of the VL-RCT in the cutting process. Additionally, cutting experiments were conducted to verify the cutting process mechanism. The results showed that the variable restricted contact structure efficiently reduced the cutting force and cutting temperature and improved the cutting performances of austenitic stainless steel. Both numerical simulation and cutting experiments reported that the trapezoidal restricted contact structure improved the cutting performance the best. Accordingly, this research provided theoretical guidance for the optimization of tool structure and the selection of cutting parameters, as well as a solid foundation for the future development of relevant design theories and methods for high-performance tools.

Bo, Wu; Song, Zhang; Weijun, Tian; Qian, Cong

doi: 10.1177/16878132231209252pmid: N/A

As the main friction pair of engine, the friction loss of piston-cylinder liner assembly in the working process has become the main reason of engine friction power consumption. Many species in the biological world have formed non-smooth forms of resistance reduction after thousands of years of survival and evolution. Many people have applied this non-smooth shape of drag reduction on organisms to the surface of friction pairs in construction machinery. Based on LX108 engine, the wear and erosion resistance of Scapharca subcrenata surface is applied to the piston skirt, which is the main friction pair in the engine. Nine test schemes were designed according to orthogonal test. This design selects three factors, namely, groove distribution type, groove depth and width, groove spacing, and each factor includes three levels. The macroscopic fluid lubrication state of the whole piston skirt with bionic shape is studied. Through the change of oil film thickness caused by thermal-mechanical coupling deformation of skirt, combined with the average Reynolds equation, the hydrodynamic pressure of lubricating oil, shear stress, and skirt friction force are obtained to verify the contribution of bionic shape to piston drag reduction, wear reduction, wetting increase, and friction power consumption. The simulation and test results show that the lubrication of all parts of the bionic groove piston skirt is better than that of the standard piston; When the depth and width of groove is 0.8 mm and the spacing is 10°, the thicker the oil film thickness of skirt is; The bionic piston whose oil film bearing area is 74%–87% of the standard piston has the smallest normal pressure and friction; When the upper end of the skirt is arranged with groove shape and the lower end is arranged with narrow groove shape between wide grooves, the lubrication effect is better.

Carne, Robert HR; Alade, Adefemi A; Orji, Berlinda O; Ibrahim, Ahmed; McDonald, Armando G; Maughan, Michael R

doi: 10.1177/16878132231210373pmid: N/A

The aims of this work were to investigate the printability of high-fraction wood and sodium-silicate composites (WSSC) for additive manufacturing and to develop a screw extrusion-based process to demonstrate this approach for building construction applications. A custom additive manufacturing system was fabricated, and mixtures of 40%–60% wood fiber and 60%–40% sodium silicate were printed. The printability of these formulations was determined by observing their viscosity, extrudability, print-bed and layer adhesion, and curing characteristics. Fiber to resin ratios of 45:55 to 50:50 were the most suitable for printing. The printability was also affected by printing temperature and nozzle travel speed. The mechanical properties of printed and cured WSSC, were determined by three-point bending, tensile, and compression testing. Tensile strength, bending strength, and elastic modulus were found to be comparable to those of 3D printed concrete and other wood-plastic composites reported in the literature. The WSSC was successfully printed into a panel indicating promise for use in additive manufacturing.

Fan, Yichu; Zhang, Wei; Li, Xiaoru; Zhu, Jianmin; Huang, Zhiwen

doi: 10.1177/16878132231210378pmid: N/A

Aiming at the problem that the current isotropic virtual material-based modeling method for dynamic modeling of sliding joints can hardly reflect the difference between normal and tangential mechanical properties, which restricts the modeling quality, a transversely isotropic material model is introduced to comprehensively describe the mechanical properties of sliding joints. Firstly, a dynamic model based on transversely isotropic virtual material and Deep Neural Network (DNN) is constructed to reflect the relationship between the dynamic parameters of transversely isotropic virtual material (Eτ,En,μτ,μn,Gn,ρ) and the natural frequencies. Then, using the cuckoo search algorithm, the transversely isotropic virtual material parameters are determined. Subsequently, as an application case, the flat and V-guide joints of the M7120D/H surface grinder are employed to validate the proposed modeling method. Finally, compared to the experimental modal test results, the error of natural frequencies is less than 1%, which achieves high accuracy. Additionally, the quantitative comparison based on the same application case shows that the proposed modeling method is superior to isotropic virtual material and spring damping method.

Chen, Junqing; Liu, Jidong; Guan, Jinfa; Han, Feng; Wu, Jiqing; Chen, Weirong

doi: 10.1177/16878132231210083pmid: N/A

During the operation of high-speed railway, the transition-point disappearance phenomenon, which is caused by the deformation of pantograph head, poses a safety threat to the pantograph-catenary system. In this study, the analytical model for transition-point disappearance analysis is presented. The instantaneous profile, as well as the deformation process of the pantograph head under different contact force values and positions or different pantograph-head parameters can be solved using the model. Curve equation, force analysis, coordinate axis rotation, and few other methods are adopted to achieve simplified modeling. The proposed modeling method and analysis conclusion provide theoretical support for the permissible contact force range calculation and pantograph-head parameters optimization to prevent transition-point disappearance. The effectiveness of the proposed model is verified using both finite element simulation and experimental measurements. Finally, a case analysis for the prevention of transition-point disappearance is conducted, using pantographs with the models CX-GI and DSA250 as examples.

Abbas, Munawar; Khan, Nargis

doi: 10.1177/16878132231207625pmid: N/A

The current study investigates incompressible, MHD flow of Cross nanofluid containing of gyrotactic microorganisms and thermophoretic particle deposition over a sheet with activation energy and variable thermal conductivity. The variable characteristic of thermal conductivity is considered as a linear function of temperature. The present study’s insights can optimize the design of nanofluid-based systems, enhance drug delivery methods, improve environmental monitoring, refine materials engineering, advance microfluidics for diagnostics, boost renewable energy technologies, and upgrade electronics cooling solutions. Moreover, this study contribution to scientific understanding will catalyze further research across disciplines, fostering innovation and progress. Cross nanofluid containing iron oxide (Fe3O4) nanoparticles, and based fluid ethylene glycol (C2H6O2) is used. In the current study, distributions of concentration, temperature, mass, microorganisms, and flow are examined in the presence of nanofluid while also accounting for thermophoretic particle deposition and a heat source. The proposed flow equations are transmuted into ODEs by employing the suitable similarity variables. RKF-45th approach is used to evaluate the reduced equations. Graphs are used to determine the effects of important factors on thermal, microorganism, concentration, and flow profiles. With a rise in the Marangoni ratio parameter, the velocity distribution is enhanced, whereas the temperature distribution exhibit inverse behavior.

Ferdows, Mohammad; Jahan, Sultana; Tzirtzilakis, Efstratios; Sun, Shuyu

doi: 10.1177/16878132231208272pmid: N/A

In modern science and technology, industrial applications that deal with the problem of continuously moving thin needle, surrounded with fluid in sectors like hot rolling, crystal growing, heat extrusion, glass fiber drawing, etc., are rapidly increasing. Such processes involve high temperatures which may affect the fluid properties that is, viscosity and thermal conductivity. So, it’s crucial to understand temperature-dependent fluid properties. Focused on these assumptions, the main objective of the current research work is to investigate how temperature-dependent fluid properties might improve the heat transfer efficiency and performance evolution of hybrid nanofluid in the presence of transverse magnetic field over a moving thin needle. Variable Prandtl number is also introduced to observe flow fluctuation, the effect of adding nanoparticles, and enhancement in heat transmission. The results are obtained for different needle thicknesses, temperature-dependent viscosity, temperature-dependent thermal conductivity, and heat generation. Moreover, Fe3O4/Graphene nanoparticles are considered to be dispersed in water. The governing partial differential equations of flow and heat transfer are transformed into a system of coupled nonlinear ordinary differential equations using analysis of similarity conversion. Subsequently, the numerical solution of the problem is attained by employing the MAPLE software. The fourth-fifth-order Runge-Kutta-Fehlberg (RFK45) approach is used by default in this MAPLE program to address the numerical problem of boundary value. The velocity and temperature field are pictured for different values of the parameters as well as physical quantities of interest such as skin friction coefficient and rate of heat transfer are visually depicted in graphs and tables. It is found that fluid motion and energy transport are highly regulated by the variation of magnetic field strength. As the volume fraction of Fe3O4 is increased, the heat generation, and thermal conductivity parameter vehemently enhance the temperature profile which leads to a rise in thermal boundary layer. A strong augmentation in the heat transfer rate has been found with the increment in the variable Prandtl number.