Bulge Height Research Articles

Investigation of the Triggering Factors that Affect the Bulge Height Estimation of SA213T91 Boiler Tube

Investigation of the Triggering Factors that Affect the Bulge Height Estimation of SA213T91 Boiler Tube

The development of undercut and bulge on a solidified surface

Abstract This study numerically investigates the development of undercuts and bulges parallel to the scanning direction on the surface solidified from a thermocapillary molten pool. The analysis considers various parameters, including power-off time, active solute concentration, beam power and radius, surface tension, liquid thermal conductivity, viscosity, and density. The formation and shapes of undercuts and bulges directly impact the yield, fatigue, fracture strength, and stress concentration in the solidified region. Unsteady two-dimensional fluid flow and heat transfer, which drive surface deformation in metals containing surface-active solutes (e.g., iron with sulfur), are solved using COMSOL Multiphase version 5.6. The development of the undercut, bulge, and molten pool is identified in six stages, based on whether the peak temperature is below the melting temperature, between the melting and critical temperatures, or above the critical temperature during heating and power-off periods. The critical temperature, determined as a function of solute content and temperature, leads to inward surface flow in the undercut near the pool edge, while the bulge in the central region can form due to either inward or outward surface flow. The predicted undercut depth and bulge height align well with previous scaling analyses and experimental data from laser polishing. These findings are relevant to various processes, including welding, additive manufacturing, polishing, melting, and solidification.

Dynamic response mechanisms of thin UHMWPE under high-speed impact

This study systematically explores the dynamic response mechanisms and energy dissipation mechanisms of ultra-high-molecular-weight polyethylene (UHMWPE) fiber laminated plates with thicknesses of 1.1 mm, 2.8 mm, and 5.4 mm under high-speed steel ball impacts through experimental, theoretical analysis, and dimensional analysis. By analyzing the damage mechanisms from experimental results, the main modes of energy absorption were identified, and a relatively accurate predictive model for ballistic limit speed was established. The results show that under high-speed steel ball impacts, the primary failure modes of UHMWPE fiber laminated plates are localized permanent bulging plastic deformation and perforation failure caused by compressive shear. The ballistic limit speeds for UHMWPE with thicknesses of 1.1 mm, 2.8 mm, and 5.4 mm are respectively 233.5 m/s, 415.7 m/s, and 602.9 m/s. The theoretical calculations of the energy model align well with the experimental results, indicating that as the speed increases, the proportion of tensile energy absorption gradually decreases, consistent with the observed phenomena. Near the ballistic limit, there are significant turning points in the level of energy absorption and the height of the rear bulge. The ballistic limit increases linearly with target thickness, and the unit area density energy absorption also increases continuously. Finally, this study established a dimensionless ballistic limit model considering the mechanical properties of fibers and the matrix, which through regression analysis, can accurately describe the ballistic limits of various strengths and types of fiber laminated plates, suitable for predicting the ballistic performance of various composite materials.

Scale analysis of undercut and bulge driven by thermocapillary convection due to surface-active solute on a solidified surface

This study scales the shape of the undercut, a depression region near the triple-phase line parallel to the scanning direction, and the bulge in the central region within the fusion zone, considering thermocapillary convection affected by a surface-active solute in the molten pool for the first time. Undercuts, commonly encountered in welding, additive manufacturing, and re-solidification processes, reduce fatigue and fracture strength while enhancing stress concentration. Utilizing the interfacial Young–Laplace equation and Bernoulli equations in the shear layer driven by thermocapillary force influenced by the surface-active solute-affected critical temperature, and introducing the concept of mass conservation, the scale analysis finds that the undercut depth and bulge height increase as Marangoni and Prandtl numbers increase, and the loss coefficient decreases. Furthermore, the widths of the undercut and bulge exhibit increases with dimensionless beam power, fusion zone width, and the ratio of solid-to-liquid thermal conductivity. The COMSOL Multiphase code is also used for simulation and successful comparison, aligning with experimental data from laser polishing. This analysis aids in understanding and controlling microstructures in various processes beyond laser polishing.

Ballistic response mechanism and resistance-driven evaluation method of UHMWPE composite

The use of ultra-high molecular weight polyethylene (UHMWPE) composite in the design of lightweight protective equipment, has gained a lot of interest. However, there is an urgent need to understand the ballistic response mechanism and theoretical prediction model of performance. This paper explores the ballistic response mechanism of UHMWPE composite through experimental and simulation analyses. Then, a resistance-driven modeling method was proposed to establish a theoretical model for predicting the bulletproof performance. The ballistic response mechanism of UHMWPE composite encompassed three fundamental modes: local response, structural response, and coupled response. The occurrence ratio of these fundamental response modes during impact was dependent on the projectile velocity and laminate thickness. The bulletproof performance of laminate under different response modes was assessed based on the penetration depth of the projectile, the bulging height on the rear face of the laminate, the thickness of remaining sub-laminate, and residual velocity of the projectile. The absolute deviations of bulletproof performance indicator between theoretical value and experimental value were well within 11.13%, demonstrating that the established evaluation model possessed high degree of prediction accuracy.

Objective Noninvasive Measurement of the Volumizing Effect of a Dermal Filler: An In Vivo Study

BackgroundInformation about the volumizing effects of dermal fillers is critical for physicians’ understanding of product features and prudent decision-making in clinical practice. It is important for material engineers to develop and optimize new dermal fillers, especially when comparing the physiochemical properties of a new product with those of existing fillers that are used worldwide.ObjectiveThis study aimed to establish a reliable, noninvasive method for in vivo quantitative evaluation of the filling effect in order to predict possible effectiveness after filler injection and to evaluate the degradation trend over time.MethodsA rabbit model of ear injection with dermal fillers was established. Hyaluronic acid (HA) filler was injected into the subcutaneous layer of rabbit ears, resulting in a stable skin bulge. Ultrasonography was used to noninvasively measure the skin bulge for volume calculation; the volume change was analyzed periodically until 38 weeks. Pathological examination, the gold standard, was performed to confirm degradation.ResultsThe immediate volumizing effect of HA filler injection was macroscopically observed as a local skin bulge. Ultrasound was able to precisely detect the shape of the filler and calculate the length, width, and height of the skin bulge at each time point. The degree of uplift and amount of residual samples in the pathological evaluation were consistent with the results of morphological observation using ultrasound.ConclusionEvaluation of the volume impact of dermal filler through the rabbit ear injection model evaluation enables material science evaluation in the early stage of material development, and has certain clinical reference value.Level of Evidence IThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

The effect mechanism of laser beam defocusing on the surface quality of IN718 alloy prepared by laser powder bed fusion

The surface quality issue of the laser powder bed fused (LPBF-ed) parts deteriorates the mechanical properties. Laser beam defocusing (LBD) can effectively improve the surface quality. To reveal the effect mechanism of LBD on the surface quality of the LPBF-ed parts, a laser powder bed fusion (LPBF) numerical model is established. Based on the calculated results, the formation process of the surface defects such as bulges, depressions, partially melted powders and spatters and the corresponding melt pool dynamic behaviors are investigated. The effects of LBD on the melt pool dynamic behaviors during the surface defects formation and the track width are discussed. The results show that LBD can improve the surface quality by reducing Marangoni force and recoil pressure to reduce bulge height and depression depth, increasing track width to decrease partially melted powders, and increasing surface tension and reducing kinetic energy to decrease spatters.

Experimental and numerical investigation of the damage state of Ti-6Al-4V alloy sheet in the tensile test, hydraulic bulging, and hydroforming processes

There has not been any damage prediction using Johnson-Cook’s (JC) hardening and damage model in the hydraulic bulging (HB) and hydroforming (HF), which are the advanced manufacturing processes, of the Ti-6Al-4V (Ti64) alloy. In the presented study, the damage behavior of the Ti64 alloy sheet in the HB and HF processes was investigated both experimentally and numerically for the first time to address the existing research gap. In this context, firstly, tensile tests (TT) were carried out on samples with different stress triaxiality values at three different tensile speeds, and the fracture morphologies of the samples were examined to evaluate whether it was appropriate to use the JC hardening and damage model. Since the fracture surfaces generally exhibit a ductile fracture morphology and are affected by stress triaxiality and strain rate, it was determined that it would be appropriate to use the JC hardening model and damage criterion to predict the damage of the Ti64 alloy in finite element analysis (FEA). Then, JC model parameters were determined by fitting the stress-strain curve obtained from the FEA and experimental tensile tests. In the HB experiments, bulging height and thickness thinning were predicted by FEA with an accuracy of 97% and 96.85%, respectively. In the HF experiments, the experimental burst pressure, die inlet radius, and base radius were predicted correctly at a rate of 92.5%, 95.5%, and 97.8%, respectively. Also, the thickness of the sample showed good agreement with the FEA results. The fracture zones in each process exhibited good agreement with the experimental results. Thus, it has been demonstrated that the JC damage criterion can be successfully applied in FEA if the Ti64 titanium alloy is damaged in various processes.

Study on the Thermal Sensitivity of Anisotropic Thin Sheets: Application to Hot Bulge Tests

This article presents a study on the thermal sensitivity of anisotropic thin sheets, focusing specifically on their behavior during hot bulge tests. Anisotropic materials exhibit different mechanical properties in different directions, and understanding their response to thermal loading is crucial for various engineering applications.
 The experimental investigation involves subjecting thin sheets of anisotropic materials to controlled thermal conditions and measuring their response. The hot bulge test, a well-established method, is employed to analyze the behavior of the sheets under elevated temperatures. This test involves applying a controlled internal pressure to a heated circular and elliptical specimen, causing it to deform and form a bulge.
 Through this study, the thermal sensitivity of anisotropic thin sheets is characterized by analyzing the bulge height, bulge profile, and strain distribution. The influence of various factors, such as temperature, material anisotropy, and loading rate, is examined to understand their effects on the sheet's response.
 Experimental results reveal significant variations in the thermal sensitivity of anisotropic thin sheets, depending on the material's orientation and temperature. The study demonstrates that certain orientations exhibit greater sensitivity to thermal loading, leading to distinct bulge profiles and strain distributions.
 Furthermore, numerical simulations are conducted using finite element analysis to validate and complement the experimental findings. The simulation models incorporate the anisotropic material properties and the thermal boundary conditions, enabling a comprehensive understanding of the thermal sensitivity behavior observed experimentally.
 The outcomes of this study provide valuable insights into the thermal behavior of anisotropic thin sheets, particularly in the context of hot bulge tests. The findings contribute to the knowledge base of material characterization and can aid in the design and optimization of structures and components subjected to thermal loading, where anisotropic materials are involved.

Coordinated deformation behavior and gas bulging formability of hot-pressed Ni/Al micro-laminated composite sheet

To fabricate NiAl complex thin-walled components, a novel Ni/Al micro-laminated composite sheet (NAMCS) was prepared by vacuum hot-pressing. Based on the uniaxial tensile tests at different temperatures, the mechanical properties of NAMCS were investigated. To clarify the uniaxial tensile coordinated deformation mechanism of NAMCS, the deformed microstructure at different tensile strains was characterized by scanning electron microscopy. The results showed that some cracks formed in NiAl3 and Ni2Al3 layers at a tensile strain of 5%, room temperature and 300 °C. At 600 °C and a tensile strain of 20%, some microvoids were observed in the NiAl3 layers, but no cracks formed in the Ni2Al3 layers until the sample fractured at a tensile strain of 78.7%. This indicated a good coordinated deformation ability. The high-temperature free gas bulging test of NAMCS showed that the limit bulging ratio (the ratio of limit bulging height to die diameter) of NAMCS at 600 °C reached 33.3%, implying good formability.

The Forming Limit Diagram of 2A16 Aluminum Alloy Sheet Based on Hydraulic Bulging Test of Elliptical Die

An elliptical die hydraulic bulging test was carried out to explore the forming performance of 2A16 aluminum alloy sheets during hydroforming. By using five groups of elliptical dies with ovality of 1.0, 0.9, 0.8, 0.6, and 0.4, the effects of different pressure rates of 0.02 MPa/s, 0.04 MPa/s, and 0.08 MPa/s on the test results were studied, and different sheets thicknesses of 2 mm and 2.5 mm were also explored, then the equivalent stress and strain values obtained by theoretical calculation were also analyzed. Finally, the complete forming limit diagram (FLD) of the 2A16 aluminum alloy sheet at room temperature was plotted through the elliptical hydraulic bulging test and the uniaxial tensile test under the same test conditions. The results show that as the ellipticity increases, the maximum equivalent stress-strain value of sheets gradually increases; reducing the hydroforming pressure rate or increasing the thickness of the sheet can slightly increase the maximum bulging height of the sheet, but it has no significant impact on the maximum equivalent stress and strain value of this material. There is no noticeable difference in the FLD on the right side, indicating that its FLD is universal for a material.

Tunable Optofluidic Curvature for Micromanipulation

AbstractManipulating micro/nanoparticles on deformed liquid interfaces induced by radiation pressure presents an active, non‐invasive, and contactless method. However, a significant challenge arises due to the relatively small magnitude of the radiation force in normal incidence. Nevertheless, this technique holds immense utility in controlling particle movement at interfaces, with numerous applications in both physical and biological contexts. To overcome this, the peculiar properties of total internal reflection (TIR) in retro‐reflection mode are expoited to create a high amplitude bulge on the water surface, which can migrate radius particles as forcibly as the traditional micro‐post paradigm. The bulge height is measured using an interferometric technique, and the underlying physics are demonstrated using an imitated particle with a capillary charge. By shining two pump lasers, an interface shape is created with increasing complexity, and the relative pump laser intensity is tuned to migrate particles in the desired direction. The method provides a non‐invasive and contactless way to remotely actuate almost all types of micro/nanoparticles at the liquid surface.

Aerodynamics and bird ingestion characteristics of a bulge-adjustable turboprop engine inlet

Turboprop aircraft plays an important role in the field of regional airliners and military transport. During take-off or landing, turboprop aircrafts frequently encounter bird flocks that can be ingested into the engine inlet, thereby posing a significant threat to flight safety. Consequently, the aerodynamic characteristics and bird ingestion characteristics of turboprop inlet are investigated in this article. An unsteady computational fluid dynamics (CFD) approach has been proposed to calculate bird ingestion characteristics in a turboprop inlet with different bulge heights under propeller interference by combining a self-developed collision-rebound model with the overset mesh method and 6-degree of freedom (6-DOF) motion method. Considering the characteristics of bird strikes, a parameterized controlled bulge of turboprop inlet with a scavenge duct has been designed. Moreover, the trajectory characteristics of the bird, bird-inlet coupling flowfield characteristics and the aerodynamic characteristics are analyzed in depth. The bulge of the inlet plays a positive role in preventing the bird object from entering the engine duct at a 23° incidence angle. The bird rebounds from the upper bulge and is discharged through the scavenge duct at MaAIP=0.45. The results show that the growth of inlet bulge height has the minimal influence on the total pressure recovery coefficient σ, with only approximately 0.3% variation within the bulge height range of interest. However, it significantly affects the total pressure distortion DC60 with an increase up to 84%.

Fabrication and characterization of microfluidic devices based on boron-modified epoxy resin using CO2 laser ablation for bio-analytical applications

CO2 laser ablation is a rapid and precise technique for machining microfluidic devices. And also, low-cost epoxy resin (ER) proved the great feasibility of fabricating these devices using the CO2 laser ablation technique in our previous studies. However, such a technique has shown negative impacts on such ER-based microfluidics as rough surface microchannels, and thermal defects. Therefore, incorporating different proportions of boric acid (BA) into epoxy resin formulation was proposed to obviate the genesis of these drawbacks in ER-based microfluidics. The structural and optical properties of plain ER- and B-doped ER-based chips were characterized by Fourier transform infrared (FT-IR) and UV/Vis spectral analyses. Furthermore, their thermal properties were studied by thermo-gravimetric (TGA) and differential scanning calorimetric (DSC) analysis. A CO2 laser ablation machine was used in vector mode to draw the designed micro-channel pattern onto plain ER- and B-doped ER-based chips. The quality of microchannels engraved onto these chips was assessed using 3D laser microscopy. This microscopic examination showed a noticeable reduction in the surface roughness and negligible bulge heights in the laser-ablated micro-channels. On the other hand, overall and specific migration using gravimetric methods and gas chromatography-mass spectrometry (GC–MS), respectively, and PCR compatibility test were performed to explore the convenience of these micro-plates for the biological reactions. These findings validated the applicability of B-doped ER-based microfluidics in bio-analytical applications as a result of the effective role of boric acid in enhancing the thermal properties of these chips leading to get micro-channels with higher quality with no effect on the biological reactions.

An Investigation on Forming and Fracture Behavior of Austenitic Stainless Steel Tubes

Tube hydroforming (THF) is an unconventional manufacturing technique that uses pressurized fluid in place of conventional punches to deform the tubular blank into the desired shape. In THF process tubular blank is deformed it into the final shape by applying fluid pressure mostly by water using water intensifier through axial punches. Tube hydroforming is mainly used to produce hollow components using tubular blank which find applications in automobile industry, particularly for exhaust systems. The formability of Austenitic stainless steel tubes as function of microstructure is not focused much in literature. Hence, in this study, formability of Austenitic stainless steel tubes is studied as a function of boundary conditions and bulge width (L/D ratio) and correlated with microstructure. Microstructure resulting in axial feed condition showed better formability than microstructure resulting in fixed feed condition. Similarly, formability and fracture behavior of tube predicted with finite element-based simulation using PAMPSTAMP 2G solver found results, particularly bulge height and fracture location are in good agreement with experimental values. The observed fracture mode noted was ductile both for axial feed condition and fixed feed condition as the fracture consists of voids and micro voids. Fracture location was in base metal just, besides, weld line for axial feed condition and fracture location was in base metal which is little away from weld line for fixed feed condition.

Improvement of material flow in tube hydroforming by advanced sealing methods

In this paper, two advanced sealing methods are proposed to enhance the formability of aluminium alloys in the tube hydroforming process. These methods are aimed at omitting friction force at the contact area between the tube and the die in the feed region and facilitating the material flow to the deformation region. The advanced sealing methods are numerically and experimentally examined against the conventional sealing method by conducting the free bulge test on AA6063 aluminium tubes. The deformation mechanics are deeply analysed in the principal strain space to identify the influence of the sealing methods on deformation paths. In addition, the effectiveness of the advanced sealing methods is evaluated under different lubrication conditions and contact lengths in the feed region. Results show that in the advanced sealing methods compared to the conventional one, the thickness in the feed region does not increase and the necking occurs in larger in-plane strains, leading to a higher bulge height. Results also allow concluding that a higher bulge height is formed using the second advanced sealing method, in which the tube is pressurized from both sides in the feed region. Thus, the advanced sealing methods are recommended for tube hydroforming of aluminium alloys with low formability.

Recycling of scrap sheet material: Enhanced joining mechanical properties of aluminum alloys by a novel auxiliary sheet flat-clinching process

Recently, lightweight aluminum alloy materials are widely used in fields such as automobiles, construction and aerospace. The joining of aluminum alloys and the green disposal of the inevitable scrap sheet material has attracted much attention. In this paper, a novel strategy is proposed for recycling scrap aluminum alloy materials as auxiliary sheets to improve the mechanical properties and reduce the joint bulge height, which is auxiliary sheet flat-clinching process. Meanwhile, the forming mechanism and failure evolution of joints were investigated, and the reasons for the auxiliary materials to increase the strength of the joints were analyzed. In addition, the influence law of different auxiliary sheet materials (AL5052-H32, AL5182-O and AL6061-T6) on the mechanical properties was revealed. From the experimental results, the auxiliary sheet flat-clinching process improves the mechanical properties of the joint caused by increasing the neck thickness. The greater the deformation resistance of the auxiliary sheet materials, the larger the interlock value, neck thickness and bottom thickness of the joint, and the smaller the bulge height. As a result, the AL6061 auxiliary sheet flat-clinching joint exhibits the best mechanical properties. Compared to ordinary flat-clinching joints, it increases energy absorption, tensile shear load and stiffness by 140%, 42% and 26%, respectively.

Ballistic performance of spherical fragments penetrating PCrNi3MoV target plates

PCrNi3MoV steel is a medium-carbon, low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation resistance. To study the penetration and failure modes of PCrNi3MoV plates impacted by tungsten spheres, tungsten spheres of various diameters (5 mm, 8 mm, and 10 mm) were used to impact PCrNi3MoV steel plates with thicknesses of 6 mm, 9 mm, and 14 mm. The penetration performance of the spheres was analyzed for different velocities, and the ultimate penetration velocity of the plate was obtained. It was found that the primary failure modes of the PCrNi3MoV plate were compression pitting failure and shear failure. Using the dimensional analysis method, a relationship between the bulge height of the steel plate and the fragment velocity, an equation for the ultimate penetration velocity, and a relationship between the target penetration energy and the fragment velocity were obtained. Then, a projectile–target action index was proposed to describe the process of tungsten spheres with different velocities impacting target plates. The results suggested that under the same thickness of the target plate, a larger-diameter fragment required more kinetic energy to obtain the same ultimate penetration effect as a smaller-diameter fragment. The equations obtained through dimensional analysis predicted values that agreed well with experimental values, indicating that these equations can be applied to engineering applications.

Infantile umbilical hernia tape fixation method without compression materials.

Compression therapy using compression material is often used for umbilical hernias in infants; however, there are problems regarding its use, such as appearance and cost. In our hospital, we use the tape fixation method without compression materials. We report the effectiveness of this method, its significance in measuring the degree of hernia bulge before treatment, and parent satisfaction with the treatment. We analyzed 77 cases of umbilical hernias (41 boys and 36 girls, mean age 52.7 ± 18.3 days) that were treated with the tape fixation method at the Department of Pediatrics of our hospital. Hernia size was classified based on the height of the bulge: mild (<1 cm), moderate (1≦ and <3 cm), or severe (>3 cm). Treatment duration was compared between the groups using the Steel-Dwass test. After the treatment, a questionnaire was mailed to the parents to assess the treatment satisfaction. Seventy-three patients (94.8%) achieved closure of the hernia orifice, with no excess skin and a well-shaped umbilicus. The duration of treatment was significantly shorter, with the following order: mild (18.5 ± 8.2 days), moderate (25.0 ± 11.9 days), and severe cases (47.8 ± 11.7 days). According to the questionnaire, 97.5% of the parents were satisfied with the treatment. Our tape fixation method without compression material achieved a high closure rate and a good shape of the umbilicus. In addition, we noted that the height of the hernia bulge can be used as a guide to estimate the duration of treatment.

Investigation of the effect of stainless-steel grain size on the continuity of graphene frictional behavior using molecular dynamics (MD) simulation

Nanograin refinement can improve the strength of stainless steel, but the substrate grain boundaries will cause graphene bulging, so it will affect the lubrication effect of graphene. In this study, the effect of stainless-steel grain size on the frictional strengthening behavior of graphene is investigated, and the mechanism of grain boundary distribution and grain boundary crossing on graphene friction strengthening behavior was revealed. A normal load constraint of 0.8 nN is set for the nano-friction process. Stainless steel grain size greater than or equal to 10 nm, the maximum friction force of graphene does not vary with grain size is about 6 nN. However, the friction strengthening behavior is discontinuous, and the friction force fluctuates significantly, which is not conducive to micromechanical structure lubrication. When the grain size of stainless steel is less than 10 nm, the frictional strengthening behavior is continuous and the friction force after strengthening will maintain small fluctuations. Since the small fluctuations of this stick–slip behavior are material properties of graphene and cannot be avoided, this state is already the ideal result for graphene lubrication. However, as the stainless-steel grain size continues to become smaller, the maximum friction of graphene will increase, which is not good for graphene lubrication. This means that after the grain size is less than 10 nm, the continuation of the grain refinement process for stainless steel will improve the strength of stainless steel, but will weaken the graphene lubrication efficiency. Moreover, the difficulty of the nanograin refinement process will be significantly increased. Therefore, the stainless-steel grain size of 7 nm by grain refinement is the best solution to balance the stainless-steel strength and graphene lubrication efficiency. With a grain size of 7 nm, the stainless-steel grain boundaries are densely distributed, and the graphene bulge area will occupy 65% of the total area, allowing for continuous frictional strengthening behavior. The maximum height of graphene bumps is 2.8 Å and the maximum friction force is about 7 nN. Meanwhile, the relationship between the grain size of stainless steel and the continuity of graphene frictional strengthening behavior was explored, and the mechanism of action of grain boundary crossing by modulating the height of graphene bulge and thus affecting the frictional maximum was revealed. The nano-friction simulation of stainless steel/graphene can clearly capture the details of the nano-friction process and the variation of friction values, providing a basis for nano-friction studies of graphene on polycrystalline material surfaces. The simulation can determine the range of stainless-steel grains that exhibit the best friction state with graphene. The simulation results also provide guidance for the refinement of stainless steel nanograins and insights for the application of nanocrystalline stainless steel/graphene in MEMS.