Uniform Load Research Articles

The influence of different load distribution considering geometric error on the fatigue life of ball screw

The ball screw pair is a precision drive component that converts rotary motion into linear motion. In practical applications, because the feed system usually has rotational torque and geometric errors, it may increase the contact load of the ball screw pair and reduce the fatigue life. In order to study the influence of different loads and geometric errors on the maximum contact load and fatigue life of ball screw pairs, the following research work was carried out. Firstly, based on the composite load and rotational torque, the ball load distribution model is established, and the accuracy of the model is verified by finite element modeling analysis. Then, the influence of different composite loads, rotation times and geometric errors (including ball size error, lead error and raceway tooth profile error) on the ball load distribution is analyzed. Finally, the influence of compound load, rotating torque and geometric error on the fatigue life of ball screw pairs is studied. The results show that the rotational torque and lead error have a great influence on the load distribution and fatigue life of the ball, and the influence of lead error on load distribution is greater than that of dimension error and tooth profile error. The fatigue life of the ball screw pair with non-uniform load distribution is shorter than that of the ball screw pair with uniform load distribution.

Elastic prolate spheroidal inclusion in an infinite elastic solid—an exact analysis of the inclusion stress by an engineering treatment of the problem based on the corresponding cavity solutions

The paper demonstrates the analysis of the stress and strain states of an inhomogeneous structure with an axial symmetrical spheroidal inclusion in an infinite solid under a remote uniform tension load derived from the conditions of the theory of elasticity. With respect to the inhomogeneous structure, the deformations produce constraints that require a complete 3-dimensional analysis in the z, r-coordinate system. The solution generates the stress state of the inclusion and at the interface of the matrix. Spheroidal inclusions in an uniform outer tension stress field deform self-similarly to a rather elongated spheroid. With respect to the compatibility condition and depending on the different elastic moduli and Poisson’s ratios in the inclusion and matrix, the solution procedure leads to a system of two linear equations with the magnitudes of the two tractions as unknowns. In this way, the solution is shortened to a twofold statically indeterminate system. The analysis performed leads to an exact solution of the general spheroidal problem in a formulation of stress concentration factors considering the different stiffness parameters of inclusion and matrix.

Anisotropy and compaction gradient assessment on rammed earth specimens through sonic tomography approach

Rammed earth is a traditional construction technique that has recently gained attention because of its benefits from an ecological perspective. The conservation of the existing valuable cultural heritage sites and the quality control of new constructions built with this material require the development and application of practical inspection techniques. This paper explores the application of sonic tests and sonic tomography as practical tools for monitoring the state of conservation of existing structures and the identification of heterogeneities or damaged areas. Two groups of 6 rammed earth specimens were manufactured and tested. The manufacturing process of each group allowed the application of compression loads and the identification of the Sonic Wave Propagation Velocities along directions parallel and perpendicular to the compaction forces during manufacturing. The SWPV were identified for the different paths between 9 measuring points located at two opposite sides of the specimens, leading to up to 6 different planes for each specimen. The SWPV are identified by identifying the Time-of-Flight of the elastic wave between each pair of excitation and receiver points. A discretized coloured map of the SWPV distribution for each plane defined by the measurement points array is obtained by the application of an algorithm already developed by the authors to obtain tomographic images for other materials and applications. The SWPV are identified after 2 different increasing values of a uniform compressive load is applied to each specimen. The results show that the analysis of the SWPV and tomographic images is sensitive to heterogeneities, such as compaction gradients from the manufacturing process, and also to the accumulated damage in the solid. The paper demonstrates that the proposed technique can be potentially used for a qualitative inspection of the state of conservation of specific rammed earth constructions.

Influence of perforation on static characteristics of the enclosing corrugated panel under the wind action

The application of the enclosing panels with perforation in construction practice for protective structures is economic advantageous due to reduction of financial costs for their production, transportation and installation. But influence of perforation on static and dynamic characteristics of the enclosing panels was not enough investigated. With the purpose of wind protection of the buildings and structures at the Ukrainian Antarctic station „Akademik Vernadsky” static stress and stability analyses of the protective structure were executed in according with the first and second groups of limit states of State building regulations of Ukraine. The protective structure as the enclosing corrugated steel panel and supporting columns was appeared. In the article the results of numeral research of the stress strain state and stability of the corrugated panel are presented. The panel width and height were accepted permanent, and a panel thickness was explored and accepted according to requirements for its stiffness, strength and stability. The four corrugations in the form of trapezoids are located along the panel height. Perforation of the panel in the form of round holes with a radius of 12.5 mm was presented. Two finite element models of the corrugated panel using the software NASTRAN were built. The corrugated panel without perforation model as a collection of rectangular shell finite elements with six degrees of freedom at the node was modeled. This model contained 35161 finite elements and 32540 nodes. The finite element model of the enclosing corrugated panel with perforation contained 383043 triangular shell finite elements with six degrees of freedom at the node and 211609 nodes. Boundary conditions were imposed on the modal nodes along the height on both sides of the corrugated panel in the form of fixing, taking into account its rigid attachment to the columns. Wind action on the enclosing panel was presented as uniform distributed static load, the limit calculation values of which were got according to State building regulations of Ukraine and statistical data of wind at the Ukrainian Antarctic station. The main attention was given to research of influence of perforation on the corrugated panel equivalent stresses and displacements, critical values of wind load and form of loss of corrugated panel stability. Computational procedures of static stress and stability analyses of software NASTRAN were applied.

Active vibration control of piezoelectric multilayers FG‐CNTRC and FG‐GPLRC plates

AbstractThis study investigates the active vibration control of multilayer Functionally Graded Carbon NanoTube Reinforced polymer Composite (FG‐CNTRC) plates and multilayer functionally graded graphene platelets reinforced polymer composite (FG‐GPLRC) plates covered with a piezoelectric layer (PZTG1195N) serve as both actuators and sensors. The plate's heart is supposed to be reinforced nonlinearly using both types of reinforcement. Active vibration control of plates under uniform load was achieved by utilizing a velocity feedback control algorithm with a specific gain value. The finite element method is employed to analyze both the static and dynamic behavior of a square plate discretized into 9‐node quadratic finite elements with 5 ° of freedom per node. The material properties are assumed to change across the thickness direction following a power law distribution, exhibiting various patterns: Uniform Distribution (UD), as well as Functionally Graded types X, O, and A (FG‐X, FG‐O, and FG‐A). The geometrical nonlinear equations are solved by the Newmark integration method. This work begins by validating the natural frequencies of a Functionally Graded (FG) composite plate reinforced with four different distributions of Nano‐filler and then aims to show the effect of the nonlinear distribution of nanofillers on the plate's stiffness. The Results obtained after the execution of a developed code highlight the significance of employing a nonlinear distribution of nanofillers to attenuate vibrations.Highlights FG composite and sandwich plates reinforced with GPLs and CNTs. Effect of nonlinear nanofillers distribution of reinforcement on free and forced vibration. The ability of the nonlinear distribution of nanofillers to attenuate forced vibrations.

Effect of Floating Support Parameters on the Load-Sharing Performance of EDPGS Based on Mathematical Statistical Methods

The encased differential planetary gear system (EDPGS) allows power to be distributed among multiple output paths, enhancing efficiency and reducing weight. Uniform load distribution ensures stable system operation and prolongs service life. However, stochastic manufacturing errors leading to uneven load distribution pose challenges in engineering practice. To investigate the impact of floating support parameters on the load-sharing performance within an acceptable tolerance band, a dynamic model of the EDPGS considering time-varying meshing stiffness and random errors is established using the Monte Carlo method. This study employs the orthogonal experimental design method to analyze the effects of floating support stiffness and clearance on the load-sharing characteristics. The findings indicate that a larger sample size leads to a probability distribution of load-sharing coefficients closer to the Gaussian distribution, with minimal influence on the expectation and variance. Furthermore, this study highlights the significant influence of floating structure parameters on load-sharing characteristics in the encased stage systems compared to the differential stage. Decreasing floating support stiffness or increasing floating clearance proves beneficial in enhancing the load-sharing performance of the system.

Selenium-modified activated coke: a high-capacity and facile designed Hg0 adsorbent for coal-fired flue gas.

The substantial amount of mercury emissions from coal-fired flue gas causes severe environmental contamination. With the Minamata Convention now officially in force, it is critical to strengthen mercury pollution control. Existing activated carbon injection technologies suffer from poor desulfurization performance and risk secondary-release risks. Therefore, considering the potential industrial application of adsorbents, we selected cost-effective and readily available activated coke (AC) as the carrier in this study. Four metal selenides-copper, iron, manganese, and tin-were loaded onto the AC to overcome the application problems of existing technologies. After 120min of adsorption, the CuSe/AC exhibited the highest efficiency in removing Hg0, surpassing 80% according to the experimental findings. In addition, the optimal adsorption temperature window was 30-120°C, the maximum adsorption rate was 2.9 × 10-2mg·g-1·h-1, and the effectiveness of CuSe/AC in capturing Hg0 only dropped by 5.2% in the sulfur-containing atmosphere. The physicochemical characterization results indicated that the AC surface had a uniform loading of CuSe with a nanosheet structure resembling polygon and that the Cu-to-Se atomic ratio was close to 1:1. Finally, two possible Hg0 reaction pathways on CuSe/AC were proposed. Moreover, it was elucidated that the highly selective binding of Hg0 with ligand-unsaturated Se- was the key factor in achieving high adsorption efficiency and sulfur resistance in the selenium-functionalized AC adsorbent. This finding offers substantial theoretical support for the industrial application of this adsorbent.

Advancing infrastructure resilience: machine learning-based prediction of bridges’ rating factors under autonomous truck platoons

AbstractThe operational characteristics of freight shipment will significantly change after the implementation of Autonomous and Connected Trucks (ACT). This change will have a significant impact on freight mobility, transportation safety, and the sustainability of infrastructure. Truck platooning is an emerging truck configuration that is expected to become operational in the future due to the rapid advancements in connected vehicle technology and autonomous driving assistance. The platooning configuration enables trucks to be connected with themselves and the surrounding infrastructure. This arrangement has shown to be a promising solution to improve the vehicles’ fuel efficiency, reduce carbon dioxide emission, reduce traffic congestion, and improve transportation service. However, platooning may accelerate the damage accumulation of pavement and bridge structures due to the formation of multiple load axles within each platoon since those structures were not designed for such loads. According to AASHTO, bridges are designed based on a notional live load model comprised of one or two trucks per lane in conjunction with or separate from an applied uniform load (AASHTO, LRFD 2022). This damage, if accumulated, its repair would require billions of dollars from the government and would impede the movement of both people and goods. The potential damage to infrastructure may arise due to various factors such as the number of trucks in a platoon, gap spacing between trucks, and the type of trucks. This research work includes a thorough parametric study with 295,200 computer simulations using SAP 2000. The goal was to evaluate the effect of different truck platooning configurations on the load rating of existing bridges. The obtained results served as the dataset for training various machine learning models, including Random Tree, Random Forest, Multi-Layer Perceptron (MLP), Support Vector Regression (SVR), K-Nearest Neighbor (KNN), and Extreme Gradient Boosting (XGBoost). Results showed that Random Forest model performed the best, with the lowest prediction errors. The proposed machine learning model has shown its effectiveness in identifying optimal platooning configurations for bridge structures within the scope of the study. Graphical Abstract

Research on the hydraulic support face guard mechanism and coupling characteristic of rib spalling in large mining heights

In view of the problem of poor coupling adaptability and easy rib spalling of coal wall in large mining height comprehensive mining, based on the effective inhibition effect of face guard mechanism on coal wall spalling, the structural characteristics and bearing capacity of different structural forms of the face guard mechanism are compared and analyzed. According to the surrounding rock adaptability of the face guard mechanism, established a numerical analysis model for rigid-flexible coupling of the face guard mechanism under different spalling forms. In order to accurately simulate the stress state of the protective mechanism, a variable stiffness spring damping system is used to replace the hydraulic cylinder. The load-bearing performance and response characteristics of the face guard mechanism under rib spalling coupling conditions were analyzed by applying uniform normal load and impact load to the face guard. The findings indicated that, the integral-type face guard mechanism has a better effect on suppressing rib spalling. When the face guard mechanism bears the static load of the coal wall, the entire response process of the face guard jack can be divided into three stages: initial support, increasing resistance bearing, constant resistance bearing; both the impact load position and the coupling state of the rib spalling will affect the characteristics of force transmission at the face guard mechanism’s hinge point, the hinge point between the extensible canopy and the primary face guard is most sensitive to biased load. The research results can provide reference for optimizing the face guard mechanism of large mining height hydraulic support and improving the reliability of coal wall support.

The influence of gear load distribution based on coupled systems on gearbox meshing noise

Introduction: With the rapid development of the gearbox manufacturing industry, the internal gear response has received attention, and the control of meshing noise during gear operation has been studied. Conventional noise reduction methods are usually based on gear order, and with the improvement of gearbox manufacturing technology, this method gradually becomes difficult to cope with a wide range of data.Methods: To expand the search domain of noise control systems, this study combines gear response and gear order, and adds the condition of gear uniform load. For common noise reduction problems in composite systems, this study improves the time-varying stiffness excitation mechanism and generates a coupled system.Results: Finally, this study conducts experiments on the Gmnoi dataset and compares it with three systems including quantum genetics to verify the superiority of the proposed system. The suppression effects of the four systems on gear meshing noise were 98.4%, 95.8%, 93.5%, and 92.7%, respectively. Their highest performance for different gear groups was 623, 514, 406, and 423, respectively.Discussion: The experimental results showed that the proposed coupling system has strong robustness and high accuracy in controlling gearbox meshing noise, and is of great significance in reducing noise pollution and improving the working environment of the gearbox.

Non-destructive experimental technique to determine ball contact load in rolling machine elements

Rolling machine elements, such as ball bearings, ball screws, or guiding systems are commonly used in diverse industrial applications. These components typically assume uniform load distribution among the balls or rely on analytical expressions. However, experimental load distribution measurement remains a challenge. This research work proposes a non-destructive experimental technique designed to determine ball contact load. The method uses painted surfaces to visualize the contact area under each rolling element, combined with an analytical formulation that modifies Hertz’s original contact equations to account for the influence of the painted layer thickness. Analytical results are compared with experimental tests on flat and curved surfaces. The results show a good agreement between the proposed painted surface formulation and measured contact areas.

Effect and performance analysis of different surface treatments on polymer-metal friction pairs

The reliability of machinery can be directly impacted by severe wear and failure of joint bearings, particularly under harsh operating conditions or after prolonged use. The study aimed to investigate the impact of various surface treatments on the properties of materials using a disc-disc contact friction machine to simulate working conditions similar to those experienced by joint bearings. The application of chrome plating resulted in a significant enhancement in performance, leading to a 20% reduction in the coefficient of friction and an 80% decrease in the wear rate to 0.071 and 1 × 10−5 mm3/(N·m), respectively, at 30 MPa and 42 mm/s. Additionally, it increased the bonding of the transfer film base by 20% compared to untreated specimens, as indicated by nano-scratch tests. On the one hand, the elevated hardness of the chrome-plated coating facilitates uniform load distribution, while on the other hand, the presence of microcracks on the surface aids in retaining a greater amount of abrasive debris and in the formation of a more effective transfer film. Consequently, this diminishes the wear of the polymer material. This discovery has the potential to influence the improvement of surface treatment procedures and the selection of materials for the advancement of engineering practices.

Research on the Calculation Method for the Load Distribution of the Dual-Input Counter-Rotating Transmission System

In order to solve the problem of an uneven load distribution in a double-input and double-output gearbox, based on the small-displacement Jacobi spin theory and considering the manufacturing and assembly errors of the gearbox, a Jacobi spin analysis model of the gearbox was established. In order to improve the accuracy of the three-dimensional tolerance analysis of the gearbox, on the basis of the processing method of parallel chain of gears and shafts and box and shafts, the serialization method of parallel chain of meshing gear pairs is proposed, and the gearbox was established. For the three-dimensional tolerance analysis model, three-dimensional tolerance analysis was carried out on the side-clearance dimensions of double-input and double-output gearboxes, and the side clearance values under the extreme value method and Monte Carlo method were deduced and combined with the theoretical side clearance to obtain the range of the side clearance of the gearboxes. Elastic deflection analysis was carried out on the gearbox shaft system, and the compensation relationship between the elastic deflection and the side clearance was investigated, so as to calculate the range of the value of the gearbox uniform load coefficient from 1 to 1.259. The error between the theoretically calculated uniform load coefficient and the experimentally tested uniform load coefficient was 6.61%, which verifies the reasonableness of the load distribution method of double-input and double-output gearboxes calculated using three-dimensional tolerance analysis combined with the elastic deflection angle, and provides a theoretical basis for the optimal design of the uniform load of multi-branch input gearboxes.

Damage Evolution Characteristics and Constitutive Model for Coal and Rock under Asymmetric Loading.

Tunnels and shaft mining roadways are often subjected to varying degrees of asymmetric loading due to terrain relief or project excavation. In order to analyze the influence of the asymmetric degree of loading on the mechanical properties and damage rupture law of coal rock, uniaxial compression tests of coal rock under four asymmetric loading modes were carried out, the influence of the asymmetric coefficients of loading on macro- and micromechanical properties of coal and rock was analyzed, and a statistical damage constitutive model of coal and rock was established to reflect the asymmetric loading degree. The results of the study show that the peak stress of the coal rock decreases gradually with the increase in the asymmetric coefficient of loading, and the two are linear functions of each other. The distribution of the acoustic emission ringing count peak value is concentrated under uniform loading, while the acoustic emission ringing count rate presents a multipeak phenomenon under asymmetric loading, and the peak value points are scattered. In the case of asymmetric loading, the stress concentration on the edge of the upper loading plate leads to shear failure, and the microscopic cracks are concentrated near the interface between the loading zone and the nonloading zone. According to the established damage constitutive model, when the damage degree is the same, the larger the asymmetric coefficient, the smaller the strain value, which indicates that the asymmetric loading promotes the damage of coal and rock.

Out-of-Plane Design Equations for Confined Masonry Walls

Nowadays there is still a lack of requirements for the out-of-plane design of confined masonry walls. Current code requirements are mainly based on the in-plane behavior of those walls. This research is divided into two parts. In the first part, two confined walls subjected to out-of-plane uniform loads were tested in the laboratory. Confining elements with minimum cross-section dimensions and wall aspect ratios smaller than one were considered. The variable studied was the wall length. Out-of-plane load—displacement curves of walls were obtained. In the second part, two design equations were developed to determine the out-of-plane strength of confined walls. A design equation was developed to determine the corresponding in-plane forces transferred to the confining elements. The out-of-plane strength of 6912 walls was determined using a computer program based on the bidirectional strut method. A parametric analysis was carried out for the out-of-plane strength considering different variables. Multiple linear regression analyses were carried out to propose out-of-plane strength design equations. It was concluded that the experimental out-of-plane strength increased, and the wall failure type changed as the wall length decreased. In addition, the experimental out-of-plane strength of walls was well predicted with both out-of-plane design equations.

Newly designed plate for the treatment of posterolateral tibial plateau fractures: a finite element analysis

BackgroundThis study investigated the biomechanical properties of a new plate used for the treatment of posterolateral tibial plateau fractures using finite element analysis.MethodsThe study groups were as follows: group PM, model of the new plate with posteromedial tibial plateau fracture; group PL, model of the new plate with posterolateral tibial plateau fracture; and group PC, model of the new plate with posterior tibial plateau fracture. We used two loading modes: uniform loading on the entire plateau, and loading on the posterior plateau. Data such as the displacement of the fracture and distribution of stress on the new plate and screws were recorded and analyzed.ResultsWhen the whole plateau was loaded, the displacement of fractures in groups PM, PL, and PC were 0.273, 0.114, and 0.265 mm, respectively. The maximum stresses on the plates in groups PM, PL, and PC were 118.131 MPa, 44.191 MPa, and 115.433 MPa. The maximum stresses on the screws in Groups PM, PL, and PC were 166.731, 80.330, and 164.439 MPa, respectively. When the posterior tibial plateau was loaded, the displacement of the fractures in groups PM, PL, and PC was 0.410, 0.213, and 0.390 mm, respectively. The maximum stresses on the plates in groups PM, PL, and PC were 194.012 MPa, 72.806 MPa, and 185.535 MPa. The maximum stresses on the screws in Groups PM, PL, and PC were 278.265, 114.839, and 266.396 MPa, respectively.ConclusionThe results of this study revealed that titanium plates have good fixation effects in all groups; therefore, the use of the new plate for posterolateral tibial plateau fractures appears to be safe and valid.

Confined Synthesis of Noble Metal Clusters Assisted by Liquid Film for Photocatalytic CO2 Reduction.

The important concept of confined synthesis is considered a promising strategy for the design and synthesis of definable nanostructured materials with controllable compositions and specific morphology, such as highly loaded single-atom catalysts capable of providing abundant active sites for photocatalytic reactions. In recent years, researchers have been working on developing new confined reaction systems and searching for new confined spaces. Here, we present for the first time the concept of a bubble liquid film as a novel confined space. The liquid film has a typical sandwich structure consisting of a water layer, sandwiched between the upper and lower surfactant layers, with the thickness of the intermediate water layer at the micro- and nanometer scales, which can serve as a good confinement. Based on the above understanding and combined with the photodeposition method, we successfully confined synthesized Ag/TiO2, Au/TiO2, and Pd/TiO2 photocatalysts in liquid film. By HAADF-STEM, it can be seen that the noble metal morphologies are all nanoclusters of about 1 nm and are highly uniformly dispersed on the TiO2 surface. Compared with photodeposition in solution, we believe that the surfactant molecular layer restricts a limited amount of precursor to the liquid film, avoiding the accumulation of noble metals and the formation of large particle size nanoparticles. The liquid film, meanwhile, restricts the migration path of noble metal precursors, allowing for thorough in situ photodeposition and enables the complete and uniform dispersion of noble metal precursors, greatly reducing the photodeposition time. The uniform loading of the three noble metals proved the universality of the method, and the catalysts showed high activity for photocatalytic CO2 reduction. The rates of reduction of CO2 to CO over the Ag/TiO2 photocatalytic reached 230 μmol g-1 h-1.This study provides a new idea for the expansion of the confined reaction system and a reference for the study of liquid film as the confined space.

Peridynamic correspondence model with strain gradient elasticity for microstructure dependent size effects

This study presents a peridynamic (PD) correspondence model with strain gradient elasticity (SGE) to capture size effect on strength of nano- and micro-scale structures. The classical elasticity theory lacking a length scale parameter does not account for the microstructure-dependent size effects. Strain Gradient (SG) elasticity is an extension of the classical elasticity with a length scale parameter(s) which can be linked to the microstructure of the material. Peridynamic theory introduces damage into the constitutive relations in a natural way by allowing for interactions of a material point within its horizon which is referred to as the internal length parameter. The correspondence model of the PD theory permits the incorporation of the constitutive relationship of SG theory. Therefore, the present approach combines the effects of PD and SGE length scale parameters on the stiffness and strength of the material. The resulting equations present two length parameters: the horizon of a material point in PD theory and the characteristic length in SGE theory. The PD equation of motion with SGE (PDSG) is free of spatial derivatives and allows for the imposition of classical and nonclassical boundary conditions. The PDSG is first applied to investigate the deformation response of a one-dimensional nanoscale film subjected to a quasi-static tensile load and a dynamic load through an initial constant strain. The static response is compared with the analytical solution for varying ratio of SG length parameter to PD horizon. The dynamic response is compared with a computational solution while satisfying the nonclassical boundary conditions. Subsequently, the PDSG is applied to study the deformation response of a two-dimensional nanoscale film subjected to a quasi-static axial load and a specified tangential end displacement. These two cases are considered under special displacement constraints to compare with the available analytical solutions. Subsequently, a two-dimensional nanoscale film with or without an internal crack is subjected to uniform tensile loading. Finally, crack propagation is simulated under incremental displacement loading. The results capture the analytical predictions and the expected increase in stiffness with increasing ratio of SG length parameter to PD horizon.

Comparative analysis of nonlinear dynamic behaviors of hyperelastic curved structure modelled by different constitutive laws

This work focuses on conducting numerical studies and comparisons on the nonlinear dynamic behaviors of hyperelastic curved structures subjected to external dynamic loadings. A numerical model of the hyperelastic structure is developed using the nonlinear finite element method, which considers both the geometric nonlinearity resulting from large deformations and the material nonlinearity due to hyperelasticity. Four commonly used hyperelastic constitutive laws, namely the Mooney-Rivlin model, the neo-Hookean model, the Yeoh model, and the Ogden model, are employed to describe the nonlinear stress-strain relationship of the hyperelastic material. The convergence performance of the numerical model with respect to grid element and time step is thoroughly examined through several numerical examples. Subsequently, based on the developed numerical model, the nonlinear dynamic behaviors of the hyperelastic curved structures excited by uniform pressure loadings with single and dual frequencies are studied and compared using various constitutive laws. The material constants used in these constitutive laws are estimated based on the well-known Treloar's test data on vulcanized rubber material. Additionally, comprehensive parametric analyses are conducted on the nonlinear dynamic behaviors of the hyperelastic structure simulated by different constitutive laws. The deformation evolution process, resonance curves, time-frequency analysis, bifurcation diagrams, and phase portraits are employed to demonstrate the similarities and differences in the nonlinear dynamic behaviors (i.e., super- and sub-harmonic resonance, internal resonance, chaotic motion and bifurcations) of the hyperelastic structure modeled by different constitutive laws.

Exceptional self-cleaning MXene-based membrane for highly efficient oil/water separation

Two-dimensional (2D) MXene-based separation membranes exhibit significant promise for oily wastewater treatment. The intercalation of TiO2 nanoparticles between MXene nanosheets can not only enlarge their interlayer distance for faster transportation of water molecules, but also promote their photocatalytic oxidation for removal of membrane fouling by oil droplets. However, the uniform loading of ultra-small TiO2 nanomaterials between MXene layers without aggregation is challenging. Herein, taking advantages of inherent Ti elements of MXene, we grew ultra-small TiO2 by in-situ one-step oxidation of MXene nanosheets to prepare 2D MXene@TiO2 heterojunctions. They were then loaded on polyethersulfone (PES) support by vacuum filtration for the PES-MXene@TiO2 composite membrane (MXTM) with exceptional water permeance and anti-fouling and self-cleaning properties. It achieves a remarkably high flux of 3045 L m−2 h−1·bar−1 and oil/water emulsion separation efficiency over 99.8%. Moreover, the MXTM membrane exhibits remarkable hydrophilicity, evidenced by an abrupt reduction in water contact angle from 43.8 to less than 5° within 10 s, which could retard the progress of oil adhesion on the membrane surfaces. The extended Derjaguin-Landau-Verwey-Overbeek theory confirmed high interaction energy between the membrane and pollutants. Furthermore, the MXTM membrane excels in self-cleaning and anti-fouling properties, retaining a flux recovery rate of >98% in 10 cycles by visible light driven photodegradation of foulants irradiation. This innovative 2D self-cleaning membrane offers excellent anti-fouling properties for efficient oil/water separation.