Mechanic of Advanced and Smart Materials

Abstract Ultra-precision machining refers to the process of manufacturing very high-precision parts that are required in industries such as aerospace, medicine, optics, and electronics, where nanometer tolerances, fine surface coatings, and precise geometries are essential. In this research, the nano-machining process of polycrystalline nickel-iron-chromium alloy has been investigated using the molecular dynamics method. Investigating the effects of cutting speed and cutting depth parameters on this process by the response surface method shows that by reducing the cutting speed from 400 to 10 m/s, the cutting depth from 5 to 0.5 nm, the values of cutting forces, normal forces and the Von Mises stress of the workpiece decreases by 65.9, 23.4 and 25.58 percent, respectively. When the cutting depth was set to 0.5 nm and the cutting speed was 10 m/s, the temperature reached 308.82 K. At this state, the machining forces—including cutting forces and Thrust force —were measured at 152.42 and 221.2 (eV/n), respectively. This configuration minimizes the machining forces, resulting in an optimized state for the machining process. The investigation of structural changes using the radial distribution function shows that increasing the cutting speed from 10 m/s to 400 m/s, while maintaining a cutting depth of 2.75 nm, results in an increase of 10 units in the radial distribution function. This change has contributed to the structural alterations of the workpiece.

Abstract In this research, the highly selective heterogeneous cation exchange membrane based on metal-organic frame works (MOFs) was prepared and introduced to electrodialysis system as hopeful material for the removal of heavy metal ions. MIL-101 (Fe) particles were fabricated via a simple chemical technique and suggested into matrix of the ion exchange membranes as additive particles. The membranes were prepared via solution casting technique by applying the desired concentrations of additive particles (0, 0.5, 1, 1.5, 2, 3 (wt%)) and then the effect of the additive particles on the morphology, electrochemical properties, and overall performance in electrodialysis system was studied. the synthesized MOF and homemade membranes were characterized using FTIR, FESEM, EDX and AFM. the images related to morphological studies showed uniform distribution of MIL-101 (Fe) particles in matrix of membranes. Utilizing MIL-101 (Fe) particles in the membrane body led to increase of surface hydrophilicity. The Water content of modified membranes was enhanced considerably compare to pristine. The membrane potential, transport number and permselectivity were increased by applying MIL-101 (Fe) loading ratio up to 1.5 wt% and then decreased. MIL-101 (Fe) membranes also, have considerable performance in removal of lead ions, so that modified sample with 2 wt% of MOF particles displayed a significant increase of 190% compare to pristine. The results are useful for electo-membrane process specially electrodialysis in order to water treatment.

Abstract The failure of the E-637 heat exchanger necessitated repairs and prompted a redesign process. Initially, the non-circular, thick-walled vessel was designed using elasticity theory and evaluated against established standards. Data for analysis and redesign were gathered from the E-637 heat exchanger at the Shazand Oil Refinery. Both analytical and numerical modeling were conducted in accordance with standard requirements and incorporated reasonable simplifications. The simulation results were compared with operational data, which confirmed the accuracy of the analysis and design process.After verifying the design's accuracy, the optimization process commenced. The final model was analyzed based on the actual configuration while considering theoretical thicknesses. Studies showed that the ASME approach tends to adopt a conservative design. Therefore, optimization was achieved through numerical simulations and adherence to standard guidelines. This process led to a reduction in the vessel wall thickness. Ultimately, by referencing the analyses in Chapter 5 of the standard, the initial thicknesses were successfully optimized.

Abstract Recent advances in nanotechnology have highlighted the need for precise and stable methods for manipulating both biological and non-biological particles. Among the available tools, atomic force microscopy (AFM) is considered a key instrument due to its high capability for controlled contact and measurement of extremely small displacements. However, maintaining stable contact between the probe tip and the particle and preventing undesired slippage, especially when dealing with complex geometries, remains a significant challenge. In this study, a dynamic modeling framework combined with sliding mode control (SMC) was proposed to enhance AFM performance during particle manipulation. Simulation results demonstrated that the designed controller could maintain the probe’s position and angle with high accuracy. Examination of three particle geometries—spherical, cylindrical, and chamfered cylindrical—revealed that slippage increased with surface complexity, with spherical particles exhibiting the least sliding (3.4%) and chamfered cylindrical particles the most (4.8%). Furthermore, a comparison of three cantilever types showed that the V-shaped cantilever achieved the best performance, with only 2.1% sliding and a significant reduction in angular fluctuations.These findings indicate that combining accurate dynamic modeling with sliding mode control provides an effective approach for developing advanced AFM systems and expanding their applications in biological studies and tissue engineering.

Abstract In the present study, the influence of aeroelastic force on the free vibration of a piezoelectric nanoplate in contact with a bounded fluid with fully simply supported boundary conditions and fully clamped boundary conditions is investigated. To model the structure, a nonlocal elasticity theory based on modified shear theories with various thickness-wise distributions for shear deformation, including exponential, triangular, and two new distribution functions introduced by the authors of this paper for the first time, is employed. The fluid considered in this analysis is assumed to be incompressible, inviscid, and irrotational, and the effects of the free-surface waves of the fluid are neglected. The aerodynamic force exerted by the airflow on the nanoplate is also modeled using first-order Piston theory. The fluid velocity potential is obtained by solving Laplace’s equation while satisfying the fluid boundary conditions, and by applying Hamilton’s principle, the governing equations for the vibrational behavior of the system are derived. After solving the equations using the Galerkin weighted residual method, numerical results are compared with published results in reputable articles to demonstrate the accuracy of the model and relationships presented in this study. Finally, the effects of various parameters, such as the geometric dimensions of the nanoplate, the nonlocal parameter, temperature variations, electric loading, fluid depth, reservoir width, aerodynamic pressure, boundary conditions, and the type of transverse shear deformation distribution along the thickness, on the frequencies and mode shapes of the vibrations are analyzed.

Abstract Laser bending of metal sheets is one of the most common forming processes and is widely used across various industries. Perforated sheets, due to their geometric discontinuities, encounter serious challenges during mechanical bending operations, which lead to ovalization of the holes and reduced dimensional accuracy. In this study, laser bending of 2-mm-thick perforated 304 stainless steel sheets is performed using a CO₂ laser, based on an experimental design developed through the response surface methodology and the Box–Behnken algorithm. For this purpose, the effects of process parameters—including laser power, scan speed, and laser beam diameter—on the percentage of hole ovalization are investigated. The results show that increasing the laser power and beam diameter increases ovalization, while increasing the scan speed reduces it. Analysis of variance of the statistical model indicates the significance of the main effects, interactions, and second-order terms of the parameters. Parameter optimization reveals that, in order to achieve minimum ovalization (0.22%), the laser power, scan speed, and beam diameter should be set to 87 W, 75 mm/min, and 2 mm, respectively.

Abstract Airborne particulate matter, such as fine dust and aerosols, poses serious threats to respiratory health. Conventional polymer filters suffer from limited reusability and sterilization challenges. This study presents the design, fabrication via Selective Laser Melting (SLM), and characterization of a cylindrical porous filter made from Ti-6Al-4V alloy with a graded conformal Gyroid topology. The structure features graded channel spacings (inner wall: 206 µm, mid-region: 396 µm, outer wall: 463 µm; weighted mean: 415 µm) and an effective open porosity of ~65%. The design was optimized in nTopology software to enhance cell overlap and particle trapping while maintaining airflow permeability. The sample (OD=15 mm, ID=9 mm, H=10 mm) was fabricated from Ti-6Al-4V powder (15–45 µm) and characterized after stress-relief annealing at 600°C. Results include optical metallography (acicular α phase in β matrix), metallographic measurements (mean layer spacing of 415 µm), Vickers microhardness (mean 327 HV), bulk density (4.18 g/cm³), and bulk porosity (~5.5%).

Abstract This study investigates the development of a gypsum-based nanobiocomposite medical plaster reinforced with cellulose extracted from sugarcane bagasse and bioactive compounds derived from rosemary (Rosmarinus officinalis) extract. Rosemary extract was employed for the green synthesis of ZnO nanoparticles, which acted as both reinforcing and antimicrobial agents. Cellulose fibers were extracted from sugarcane bagasse through alkaline treatment followed by hydrogen peroxide bleaching, yielding a lightweight, white, and impurity-free material. Nanobiocomposite samples were prepared by incorporating the ZnO nanoparticles and rosemary extract into medical-grade gypsum, and their mechanical and antimicrobial properties were evaluated. To identify and characterize the synthesis of nanoparticles and investigate their physicochemical properties, tests including UV-Vis, SEM, XRD, and FTIR have been used. Antimicrobial assays demonstrated that green-synthesized ZnO nanoparticles exhibited significant antibacterial activity against Staphylococcus aureus and Escherichia coli, while rosemary extract nanoparticles showed moderate activity against S. aureus only. Impact resistance testing revealed that the addition of nanoparticles increased the absorbed energy of cellulose-reinforced gypsum, with ZnO-containing nanocomposites achieving the highest values at 5 wt.% reinforcement. Overall, the integration of cellulose and rosemary-derived ZnO nanoparticles into gypsum enhances both mechanical strength and antibacterial performance, suggesting potential applications in medical plasters and protective coatings.

Abstract The process of drilling trabecular bone is one of the most challenging stages in orthopedic surgeries. An increase in cutting force during drilling may lead to thermal necrosis of the bone, infection, and tool failure. However, comprehensive studies on drilling trabecular (cancellous) bone—which plays a vital role in the structural and physiological integrity of the bone—are limited. In this study, in order to analyze the effects of machining parameters including spindle speed, feed rate, and drill diameter on cutting force during drilling, the Response Surface Methodology (RSM) with a Central Composite Design (CCD) was employed to develop second-order mathematical models, accompanied by quantitative sensitivity analysis based on the Sobol method. Analysis of variance (ANOVA) indicated that the proposed models exhibit high accuracy. According to the results, medium spindle speeds, smaller drill diameters, and higher feed rates reduce drilling forces. Sensitivity analysis using the Sobol method demonstrated that spindle speed (59.6%) is the most influential parameter governing the drilling force. These findings provide a solid foundation for developing robotic surgical systems with intelligent control of machining parameters and enhancing intraoperative safety.

Abstract This paper presents a comprehensive vibrational and static analysis of a soft actuator considering nonlinear effects. Fluidic channels embedded within a soft beam are considered a soft robotic actuator, exhibiting nonlinear characteristics due to the inherent properties of the soft material. The analytical process is based on Hamilton's principle, and the numerical solution has been carried out using the finite element software ANSYS, utilizing the Fluid-Structure Interaction (FSI) and Pre-stress Modal tools. Initially, time-dependent inlet pressure is applied, and the resulting pressure distribution within the soft fluidic actuator (SFA) is extracted over the time domain. Following the validation of results obtained from finite element software and analytical methods, the feasibility of using this actuator as an artificial muscle in a robotic fish has been examined, leveraging the phenomenon of resonance and analyzing its behavior under real-world conditions. The findings indicate that utilizing this type of actuator in the robotic fish's tail enables functional similarity to a real fish after 8 seconds. However, by applying the proposed method and tuning the operating frequency closer to the system’s natural frequency, the robot can immediately exhibit movements resembling those of a biological fish.

Abstract This study investigates the quantification of uncertainty in the buckling behavior of imperfect spherical shells subjected to external pressure and examines the sensitivity of parameters influencing the critical buckling load. In this framework, initial geometric imperfections, thickness variations, variations in material mechanical properties, and boundary condition uncertainties are considered as the primary sources of uncertainty in the model. The numerical results indicate that increasing the shell thickness leads to a nonlinear increase in the critical buckling load, whereas an increase in the amplitude of geometric imperfections has the most significant contribution to the reduction of buckling capacity. Furthermore, variations in elastic material properties and boundary conditions can result in shifts in buckling modes and changes in the instability mechanism. Sensitivity analysis reveals that the geometric imperfection amplitude and the thickness-to-radius ratio are the dominant parameters governing the buckling behavior of spherical shells. In the second stage, a multilayer perceptron artificial neural network was employed for rapid modeling and prediction of buckling behavior. Data obtained from the numerical analyses were used as the training and testing datasets for the network. The results demonstrate that the neural network model is capable of predicting the critical buckling load and dominant instability mode with satisfactory accuracy and shows a strong correlation with finite element analysis results. These findings indicate that combining nonlinear numerical analysis with artificial intelligence-based modeling provides an efficient framework for reliability-based design of imperfect spherical shells and significantly reduces computational time without compromising prediction accuracy.

Abstract The perturbation friction process is a solid state method used to modify the surface, improve mechanical properties, and produce composites. In this research, the effect of effective parameters on the surface compositing of AZ31B / CNT alloy with carbon nanotubes has been investigated by the frictional perturbation process method and Sobel sensitivity analysis. Input parameters in this study were advance speed, rotation speed, weight percentage of carbon nanotubes and number of welding passes, as well as considered outputs including hardness and weight loss. In order to analyze the results, Sobel sensitivity analysis has been used to investigate the qualitative and quantitative impact of inputs on outputs. The results of this study showed that the weight percentage of carbon nanotubes, rotation speed, number of welding passes and advancement speed affect hardness, respectively. The weight percentage of carbon nanotubes, the rotation speed, the number of welding passes and the advancing speed also affect the weight loss.

Abstract In this paper, the optimization of effective parameters on the process of severe plastic extrusion deformation in the torsional angular channels of the plate is investigated. Initially, the process test was designed using the response procedure method, and four main and influential input variables on the process, torsion angle, radius, channel angle, and coefficient of friction, were extracted, and the regression equations of each for the mechanical properties of the samples produced by this method. Using sensitivity analysis, which is very useful in the production of parts and industry today, and by using it, the quality of manufactured parts can be greatly improved and production costs can be reduced to a large extent, the effect of input variables on plastic strain Parts checked. In this paper, the mean and maximum strain and maximum force, which are defined under the influence of these input variables, have been investigated and analyzed using the e-Fast statistical sensitivity analysis method. The results of the analysis show that the mean strain is affected only by the values of torsional and channel angles, but the maximum strain is affected by the coefficient of friction and has a direct linear relationship with its changes. The maximum force is also in a balanced state from the effect of the variables. Also, the quantitative effect of torsion angle of 52% and channel angle of 48% on mean strain and coefficient of friction with 86% and torsion angle with 42% had the greatest effect on the strain and maximum force.

Abstract Nanoparticle manipulation is a process in which particles are moved on a micro/ nanoscale scale using an atomic force microscope and has a wide range of applications from component production to the medical world. In this study, using the theories of contact mechanics of Hertz, JKR, DMT and BSP, as well as using the structure of the DNA biological cell using the Elman method using ABAQUS software to study the amount of displacement, acceleration, force, stress and velocity in time The DNA molecule is discussed on a base sheet and the factors that affect them. The results show that in the deformation between the target particles and the spherical tip of the needle, the Hertz model showed the least and the JKR model showed the highest deformation and penetration depth. By increasing the angle of the needle tip with the z-axis, the amount of penetration depth and deformation created between the particle and the base plate is reduced. Also, the graph of changes in each of the studied parameters of the effective factors per 20 μm of displacement and 20 milliseconds of time for the DNA manipulation process has been calculated.

Abstract Metamaterials are materials that exhibit unusual properties. Auxetic materials, as a class of metamaterials, are structures with a negative Poisson ratio. These materials become thicker when applied under tensile stress, unlike conventional materials, in the perpendicular direction to the applied force, and become thinner when applied under compressive stress. Auxetic behavior is an independent property that can be obtained from microscopic or macroscopic levels and even molecular or cellular levels. Many structures and materials are known of this feature. This unique feature has created potential applications in the military, aerospace, medical and intelligent sensors, and many other industries. However, there are still many problems with the widespread use of these structures. This paper provides a comprehensive review of these structures that have unique properties and applications of auxetic materials. In addition, some of the latest developments in these materials are described. Materials with a negative Poisson ratio have great potential in various applications such as lightweight structures or biomaterial applications.

Abstract In recent years, gecko-like dry adhesives have been used in robotic grippers and climbing robots. The adhesive has been introduced as a new approach for manipulating flat objects in production lines. The method has several advantages over other, more traditional, gripping methods such as lower power consumption compared to suction-based systems or the ability to handle non-magnetic materials. Directional Gecko-like adhesives are based on the frictional adhesion and employ asymmetric feature, mostly wedge shape, and perform only in one direction. In this paper, design and fabrication process of a new pyramid shape Gecko-like adhesive using silgard 184 has been described. The new microstructures has the ability of adhesion in several directions, and the contact surface between the adhesive and substrate increases and the possibility of self-sticking between adjacent stalks decreases. Chemical machining and microlithography were used for manufacturing molds in this research and the details were described. The performance of proposed adhesive was evaluated using an experimental set-up and adhesion force was measured on different substrate. During experiments, adhesion was controlled via applied shear force to adhesive. The experimental results showed 30% increase in adhesion using proposed adhesive in comparison with the existing similar adhesive.

Abstract Composite shells are widely used in various industries due to their low weight and high strength. Designing these structures involves various engineering analyses, and one of the most important studies is the investigation of the buckling of shells under axial load. The aim of this research is to investigate the vibrational correlation method on composite cylinders with delamination defects. Delamination defects can occur in structures under different conditions and have a significant impact on the strength of the cylinder. Therefore, in this study, different dimensions and quantities of delamination defects in various specimens were examined using the vibrational correlation method. Carbon fibers of type T300 were used as the reinforcement material, and the epoxy resin LY556 was used as the matrix. The hardener and accelerator combined with the resin in this research are HY917 and DY70, respectively. The layer stacking in the specimens was done with angles [55 90 90 55] using the filament winding method, and artificial delamination defects were created between layers 2 and 3 using Teflon sheets. The manufactured specimens were subjected to modal testing under various compressive forces, and then the critical buckling load of the specimens was obtained using the modal testing method. Using numerical modeling software, critical buckling loads and natural frequencies were calculated for various axial compressive loads through linear and nonlinear analysis. These numerical results were compared with experimental results. The vibrational correlation method accurately predicted the critical buckling load in defect-free specimens with a 3% error, but its accuracy was significantly

Abstract The wheeled mobile robots have many applications due to their advantages such as wide workspace, mobility and maneuverability. Intelligence of mobile robots to perform autonomous movements is also one of the favorite fields of robotics researches. In this paper, the trajectory tracking of an intelligent mobile robot on a sloping surface is studied using a nonlinear sliding mode control. First, the nonlinear dynamic equations of a wheeled mobile robot are derived on a sloping surface using the Newton-Euler method. A multistage nonlinear control block is then proposed for trajectory tracking. First, the controller calculates the linear and angular velocity of the robot to find the position of the robot, and then, assuming uncertainties in the dynamic model, a sliding model controller is used to track the robot's specific path. Various simulations are presented to validate the control method, which the results show the capability and efficiency of the proposed method.