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The proposed method involves the utilization of a strip roll-forming technique to fulfill the specific requirements for constructing large-scale structures in orbit and space station trusses during extraterrestrial exploration. This involves progressively rolling out a metal strip with an L+V-shaped locking edge through multiple passes of forming rolls featuring different section shapes. The process of helical locking enables the formation of a slender, spiral-shaped tube, which can be utilized for the in-orbit assembly of exceptionally large structures. The proposed approach introduces a two-step optimization method to enhance the maximum stress, equivalent plastic strain, and wrapping torque of roll-forming L+V cross-sections and wrap-forming helical tubes. The optimized sample points in the second step are established based on the optimal roll distance and roll gap obtained in the first optimal step, resulting in the determination of the optimal folding height and V-shaped angle of the L+V strip cross-section after optimization. The design of the strip wrapping configuration that follows is highly dependent on these four parameters. [ABSTRACT FROM AUTHOR]

The proposed method involves the utilization of a strip roll-forming technique to fulfill the specific requirements for constructing large-scale structures in orbit and space station trusses during extraterrestrial exploration. This involves progressively rolling out a metal strip with an L+V-shaped locking edge through multiple passes of forming rolls featuring different section shapes. The process of helical locking enables the formation of a slender, spiral-shaped tube, which can be utilized for the in-orbit assembly of exceptionally large structures. The proposed approach introduces a two-step optimization method to enhance the maximum stress, equivalent plastic strain, and wrapping torque of roll-forming L+V cross-sections and wrap-forming helical tubes. The optimized sample points in the second step are established based on the optimal roll distance and roll gap obtained in the first optimal step, resulting in the determination of the optimal folding height and V-shaped angle of the L+V strip cross-section after optimization. The design of the strip wrapping configuration that follows is highly dependent on these four parameters.

A novel optimisation process has been proposed in this paper to maximize the aerodynamic efficiency of a modern fan blade while satisfying the structural constraint imposed by the material limits. The method developed is based on the discrete adjoint for the aerodynamic efficiency sensitivity evaluation with the structural constraint provided by a response surface method for the structural stress. To facilitate a large number of sampling points required in the response surface generation, a fast, meshless method was used for the stress calculations. The method was applied to the optimisation of a practical fan blade, representative of modern, high-bypass-ratio turbofan jet engines. It is demonstrated that the fan blade efficiency can be improved by 0.6% while maintaining the stress below a prescribed value of 500 MPa assuming a titanium alloy material. It is shown that without the stress constraint, the efficiency benefit is larger, namely 0.9% but the maximum stress value increases considerably beyond the material's acceptable criterion, to almost 1000 MPa. The method is built in a modular way and can be adapted to accommodate a range of different turbomachinery blade designs. Flutter analysis for the optimised fan blade has also been carried out due to its practical importance. [ABSTRACT FROM AUTHOR]

To study the dynamic mechanical properties of rock materials under seismic loads, seismic loads are generally simplified to constant amplitude cyclic loads due to the limitations of test equipment and conditions. However, the characteristics of rock material under seismic load are rarely reported, and the difference between the dynamic deformation properties of rock material under seismic load and cyclic loading is unclear. Therefore, it might be unreasonable that the seismic loads are generally simplified to constant amplitude cyclic loads. Thus, to find a reasonable equivalent form of seismic loads, Kobe wave was selected as a case study. Based on the dynamic constitutive model for rock materials suited to dynamic cyclic loading proposed by Zhou et al. (2022), the dynamic mechanical properties of a rock material (T2y6 marble) under the seismic load and three common dynamic cyclic loadings (including constant amplitude cyclic loading, tiered cyclic loading, and symmetrical tiered cyclic loading) with four different maximum stresses were simulated. And the difference of the properties of rock under the seismic load and dynamic cyclic loading are analyzed by considering the deformation, modulus, and damage of the rock. The results show the stress-strain curves of the rock under seismic load exhibit the cyclic behavior of rock materials, while the size and range of loading and unloading in each cycle are different. Moreover, the smoothness of variation in plastic internal variable of rock and the damage under seismic load is weaker than that under these three cyclic loading regimes. Furthermore, the order of final strain, maximum plastic internal variable, maximum deformation modulus and final deformation modulus of the rock under different loads varies. Overall, the symmetrical tiered cyclic loading can be the best choice of these three cyclic loading to study the dynamic properties of rock under seismic load. Finally, steps necessary to determine the corresponding symmetrical tiered cyclic loading of a seismic load are provided. [ABSTRACT FROM AUTHOR]

In order to study the influence of surface circumferential crack defects on pipelines， based on the extended finite element method(XFEM)， a numerical simulation study was carried out on the crack propagation law of the X60 steel pipeline with circumferential circular surface cracks using the finite element software ABAQUS. Furthermore，the effects of crack location，internal pressure and initial crack size on the circumferential propagation of surface crack were discussed， and the maximum stress of the pipeline with cracked defects only under the action of internal pressure as well as the tensile displacement of the pipeline when the crack expands and penetrates the pipeline wall were analyzed.Results showed that the maximum stress on the pipeline was at the tip of the crack， and the stress there decreased after the crack expanded.When only under the action of internal pressure， the maximum stress of the pipe with circumferential cracks increased linearly with the rising of internal pressure， and the initial size and location of the crack had little effect on the maximum stress of the pipeline with circumferential cracks. Under the effect of axial displacement， the initial size of the crack had a significant influence on the displacement when the crack propagated. The axial displacement of the pipeline when the crack expands and penetrates the pipeline wall decreased rapidly with the rising of the crack size. When the crack size was in a certain range， the axial displacement of the pipeline when the inner wall crack expands and penetrates the pipe wall was smaller than the outer wall crack， which indicated that the crack on the inner wall was more dangerous. After the cracks increased to a certain size， the outer wall cracks became more dangerous.

This study proposes a novel approach to optimize the structure of the hinge beam in cubic presses, aiming to enhance the safety and reduce costs. The finite element method is used to analyze the stress distribution of the hinge beam under operating conditions, revealing a significant stress concentration at the oil inlet edge. To optimize the structure, the Taguchi method, the NSGA-II multi-objective optimization algorithm, and the entropy-TOPSIS method are combined to consider both the maximum stress and total weight. The results demonstrate a reduction of 199.121 kg and 11.97 MPa in the total weight and maximum stress of the hinge beam, respectively, representing a decrease of 4.12% and 1.72%. Furthermore, the simulation results of the optimal structure demonstrate a high degree of accuracy, with only 0.27% difference between the algorithm-optimized and simulation values. The proposed optimization method not only improves the efficiency of the optimization, but also avoids the mutual exclusion between the maximum stress and total weight. It significantly improves the reliability of the hinge beam and reduces its manufacturing costs, thereby shortening the development cycle of the new hinge beam. [ABSTRACT FROM AUTHOR]

BACKGROUND: The mechanical response of trabecular bone under loading can be studied using micro-CT based micro-finite element. It is generally considered that bone volume fraction in animal specimens is the most important index that determines the compressive strength of trabecular bone. However, in the micro-CT based finite element model, the microstructural index leading to stress concentration or determining the maximum stress is not clear. OBJECTIVE: To investigate the microstructural indexes that affect the maximum stress of trabecular bone micro-finite element model. METHODS: The microstructural indexes of trabecular bone of 10 normal rats from bilateral femoral metaphysis region of interest were obtained and the differences of trabecular bone in bilateral regions of interest were compared. The 20 trabecular bone finite element models were constructed and loaded. The average stress values of the ranking 5%, 2%, 1% and 0.5% of stress value were taken as the maximum stress value. The reliability of the models was verified according to the stress and effective strain. Finally, with the maximum stress value as the dependent variable and the trabeculae microstructural index as the independent variable, the key factor affecting the maximum stress of trabeculae micro-finite element model was explored by multiple linear stepwise regression method. RESULTS AND CONCLUSION: There was homogeneity in trabecular bone microstructure of bilateral femoral metaphysis (P > 0.05), and then data were combined. The average number of elements and nodes of 20 trabeculae finite element models was 232 813 and 606 82. The average stress of the ranking 5%, 2%, 1% and 0.5% elements was 31.91, 41.96, 50.86 and 61.23 MPa, respectively, and the average effective strain was 3.28%. The results of multiple linear stepwise regression analysis indicated that the structure model index was the most important factor influencing the maximum stress of trabeculae finite element model (P < 0.001, R2 =0.807). It is indicated that the trabecular bone structure model index is the most important bone microstructure index that affects the stress concentration of the trabecular bone micro-finite element model. [ABSTRACT FROM AUTHOR]

Optimization means the mathematical determination of the optimal decisions out of diverse alternatives. Based on the preceding Finite Element Analysis (FEA), a proposed shell produced a maximum stress that exceeded the design value. To make the design feasible, an optimization was done to minimize the maximum stress by using the gradient method. The performance of the structure can be optimized to fulfil the design requirements with the optimum value of displacement to achieve the objective function. The results show that the optimum displacement is 8.8mm, which reduced the maximum stress by 99.94% from the initial level. Thus, optimization methods are important for new applications of shell structures to find their best parameters in the design stage.

It was challenge to balance the large turning angle and low stiffness of multiple-cross-springs flexure pivots with straight beams. The multiple-cross-springs flexure pivots with arc curved beam springs was designed to reduce the maximum stress and rotational stiffness. The high rotation accuracy and large stroke were obtained under pure torque driving conditions. The calculation equation of deformation stress of the arc curved beam springs was deduced, and the large deformation mechanicals analysis model of the flexure pivots was established. The accuracy of the theoretical model was verified by the rotation stiffness experiments and the deformation stress simulation calculation. Moreover, the relationship among the driving torque and deformation stress of the flexure pivots and the design variables, radius coefficient, spring curvature and configuration angle was discussed by using the deformation model. Some design schemes to reduce the rotation stiffness and deformation stress concurrently were proposed. The appropriate variable combination for the flexure pivots to obtain zero stiffness characteristics and negative stiffness characteristics were determined. The designed flexure pivots and the rotation characteristics analysis results provide a reference for the design of a new type of large-stroke flexure pivots. [ABSTRACT FROM AUTHOR]

This study is intended to improve the methodology to calculate the tensile properties of natural coconut fiber and increasing confidence in the use of sustainable natural fibers as reinforcing in composites used for different components in the naval industry. Coconut fiber is an agribusiness by-product that has been shown to have the potential for the development of new materials. The morphology of different species of coconut fiber was studied, and their mechanical tensile properties were determined. The coconut fibers were tested under direct tension in a universal testing machine, and the cross-sectional area of the fibers was calculated using images obtained in an optical microscope and a scanning electron microscope. The study assessed the incidence of key factors to determine coconut fiber mechanical tensile properties including different area measuring methods and the percentage of lumens present through an image analysis software called ImageJ. The results indicate that coconut fiber has a round-shaped cross-section, and the percentage of lumens is between 15% and 27%. Therefore, the effective area is reduced increasing the fiber's ultimate resistance to tension. [ABSTRACT FROM AUTHOR]

Long-term geological storage of carbon dioxide in underground engineering is the most economically viable option for reducing emissions of this greenhouse gas to the atmosphere. Underground engineering projects are often subjected to earthquakes during their lives, thus it is essential to investigate the deformation characteristics of surrounding rock of those underground engineering works subjected to seismic load under different confining pressures. To date, however, there have been notably few studies on the characteristics of rock materials under seismic load and the influences of seismic load on dynamic deformation properties of rock material under different confining pressures remain unclear. Therefore, a numerical study of the dynamic mechanical properties of a rock material (T2y6 marble) under Kobe seismic load with four different maximum stresses and four different confining pressures was conducted. The results show cyclic behavior, strain rate effect and damage are found in the stress-strain curves of the rock under simulated Kobe seismic load. Confining pressure can significantly limit the increases in lateral strain and volumetric strain, thus dilation can occur in the rock when the maximum stress of seismic load is large, and the confining pressure is small. Seismic load with small maximum stress cannot cause severe damage to the rock, but the influence is larger than that of static load. The maximum stress can be treated as a main factor affecting the damage to rock under seismic loads, while the effect of confining pressure thereon is smaller than that of the maximum stress. Furthermore, the relationships between deformation characteristics of the rock under these seismic loads, such as maximum strain, residual strain, plastic internal variable, deformation modulus, and maximum stress are different from that between the deformation characteristics and confining pressure.

The hull structure is a vital part of a ship that supports internal and external loads. Failure that often occurs in the hull structure is due to maximum stress at the meeting point of the hull plate arrangement. The purpose of this study is to analyse and optimize a certain design of the connection plate at the meeting point of the hull plate arrangement to reduce maximum stress. A diamond plate innovation was applied, which is a plate with a diamond shape that aims to reduce the maximum stress at a certain angle. The method of this study is finite element analysis modelling supported by metallographic data. As a comparison analysis, two external loading conditions were carried out, i.e., hogging and sagging conditions; furthermore, the variations of the diamond plate were also carried out to obtain the optimum dimensions. The results of this study show that the plate arrangement using a diamond plate can reduce the maximum stress under hogging and sagging conditions, reaching 37.2% and 33.1%, respectively.

Highlights: The dynamic behaviors of rock under different seismic loads are numerically simulated. The properties of rock under different seismic loads are analyzed and compared. The main factors of seismic load for the deformation properties of rock are determined. [ABSTRACT FROM AUTHOR]

Optimization means the mathematical determination of the optimal decisions out of diverse alternatives. Based on the preceding Finite Element Analysis (FEA), a proposed shell produced a maximum stress that exceeded the design value. To make the design feasible, an optimization was done to minimize the maximum stress by using the gradient method. The performance of the structure can be optimized to fulfil the design requirements with the optimum value of displacement to achieve the objective function. The results show that the optimum displacement is 8.8mm, which reduced the maximum stress by 99.94% from the initial level. Thus, optimization methods are important for new applications of shell structures to find their best parameters in the design stage. [ABSTRACT FROM AUTHOR]

The relevance of the research is caused by the need to build an earthen bed, including an earthen bed of intra-field roads on the territory of NK Rosneft PJSC, in difficult engineering and geological conditions. At the same time, the total length of roads is several thousand kilometers. It is also necessary to note the emergence of a huge assortment of geotextile reinforcing materials, the use of which is a modern effective way to solve the problem of improving the reliability of earthworks, including the issue of reducing the precipitation of embankments of the earthwork, which should lead to optimization of funds by reducing the volume of earthworks. The main aim of the research is to optimize capital expenditures for the construction of intra-field roads on a weak base due to reinforcement of embankments with local (lay flooring) or geosynthetic materials. Object: soil embankment. Subject: sedimentary phenomena of the soil of the earth on a weak base, depending on the type of fortification. Methods: retrospective analysis and comparison method. The precipitation was calculated by layer-by-layer summation, and a graphoanalytic method was used to determine the final precipitation Skon and the calculated load P. To calculate the settlement of the embankment, taking into account the reinforcement of the roadbed with a sunbed or geo-nut, a mathematical modeling method was also used. Results. The paper introduces the calculations of substantiation of perspective of applying the alternative materials at strengthening roadbed on weak base. To confirm the cost-effectiveness of the proposed solutions, a technical and economic comparison of two options for reinforcing the structure of the roadbed was made: a bed flooring and a geo-nut – with a model without reinforcement. The economic effect of using the reinforcement of the roadbed on a weak base was determined.

This study proposes a novel approach to optimize the structure of the hinge beam in cubic presses, aiming to enhance the safety and reduce costs. The finite element method is used to analyze the stress distribution of the hinge beam under operating conditions, revealing a significant stress concentration at the oil inlet edge. To optimize the structure, the Taguchi method, the NSGA-II multi-objective optimization algorithm, and the entropy-TOPSIS method are combined to consider both the maximum stress and total weight. The results demonstrate a reduction of 199.121 kg and 11.97 MPa in the total weight and maximum stress of the hinge beam, respectively, representing a decrease of 4.12% and 1.72%. Furthermore, the simulation results of the optimal structure demonstrate a high degree of accuracy, with only 0.27% difference between the algorithm-optimized and simulation values. The proposed optimization method not only improves the efficiency of the optimization, but also avoids the mutual exclusion between the maximum stress and total weight. It significantly improves the reliability of the hinge beam and reduces its manufacturing costs, thereby shortening the development cycle of the new hinge beam.

The paper presents the research results of the response of "Ramos" potatoes under impact loading conditions. The parameters characterizing the impact such as: maximum stress, maximum force, impact time, maximum deformation, permanent deformation and restitution coefficient were determined. The extent of the damage was also assessed on the basis of the parameters describing the particular bruise such as: bruise depth and width. The impact parameters were related to the bruise size in order to determine the damage threshold for the potatoes under impact loading conditions and to show which parameters describe the bruise beginning to manifest itself. For the tested potato cultivar with a weight of 160-190 g the initiation of the bruise was found to occur at an impact velocity of 1 m s-1. This corresponded to a bruise threshold (drop height) of 50 mm. The restitution coefficient changed to an insignificant extent which amounted to 0.44-0.49 in the tested range of the impact velocity which proves that the energy losses during the potato impact are constant and independent of the impact velocity. The maximum stress increased with increasing impact velocity, reaching a constant value of 0.9 MPa for the highest impact velocities. The stabilization of the maximum stress indicates that the damage to the potato tissue was determined by exceeding the specified stress value. [ABSTRACT FROM AUTHOR]

BackgroundSpinal cord ischemia is largely caused by cervical spondylotic myelopathy (CSM), which has a corresponding biomechanical basis. Finite element analysis of spinal cord stress in diseased segments of CSM was performed to provide a biomechanical basis for the pathogenesis of CSM.MethodsA single segment (C4-5) in a patient with CSM was selected for mechanical simulation of three-dimensional (3D) computed tomography scanning, and a 3D finite element model of the cervical vertebra was constructed. Based on the patient's age, sex, height, weight, and other parameters, a finite element analysis model of an individual with healthy cervical vertebrae in our hospital was selected as the control to compare the stress changes between the patient and control groups in the analysis of the cervical vertebrae under anterior flexion, posterior extension, lateral flexion, and rotating load in the diseased spinal cord segment.ResultsIn the CSM patient, the diseased segment was C4-5. Under loading conditions of forward flexion, posterior extension, left flexion, right flexion, left rotation, and right rotation, the maximum stress on the spinal cord in the control group was 0.0044, 0.0031, 0.00017, 0.00014, 0.0011, and 0.001 MPa, respectively, whereas those in the spinal cord in the CSM group were 0.039, 0.024, 0.02, 0.02, 0.0194, and 0.0196 MPa, respectively.ConclusionThe maximum stress on the diseased segments of the spinal cord in the CSM group was higher than that in the control group, which contributed to verifying the imaging parameters associated with spinal cord compression stress.

Based on an actual ultra-high voltage (UHV) substation, a finite element (FE) model for a high-voltage (HV) bushing, arrester, and down lead transmission line (DLTL) system was built using ANSYS software. The dynamic responses of the system under different seismic intensities were analyzed and compared with those of the corresponding single bushing and arrester. On this basis, the coupling vibration influence of the upper DLTL on the responses of the HV bushing and arrester is discussed. The results indicate that the DLTL adversely affects the responses of the HV bushing and arrester under seismic loading. As the seismic intensity increases, the structural displacements at the top of the HV bushing and arrester increase, accompanied by a reduction in the geometric length redundancy of the DLTL, resulting in a mutual pulling effect between the HV bushing and the arrester and the quick amplification of their respective dynamic responses in a nonlinear form. Under the action of an earthquake with a peak ground acceleration (PGA) of 0.4 g, the maximum stresses at the roots of the HV bushing and the arrester in the system separately increase by approximately 13.02% and 7.80% compared to the corresponding single HV bushing and the arrester. Overall, a geometric length redundancy of at least 200 mm in the DLTL in engineering design is recommended. [ABSTRACT FROM AUTHOR]

The hull structure is a vital part of a ship that supports internal and external loads. Failure that often occurs in the hull structure is due to maximum stress at the meeting point of the hull plate arrangement. The purpose of this study is to analyse and optimize a certain design of the connection plate at the meeting point of the hull plate arrangement to reduce maximum stress. A diamond plate innovation was applied, which is a plate with a diamond shape that aims to reduce the maximum stress at a certain angle. The method of this study is finite element analysis modelling supported by metallographic data. As a comparison analysis, two external loading conditions were carried out, i.e., hogging and sagging conditions; furthermore, the variations of the diamond plate were also carried out to obtain the optimum dimensions. The results of this study show that the plate arrangement using a diamond plate can reduce the maximum stress under hogging and sagging conditions, reaching 37.2% and 33.1%, respectively. [ABSTRACT FROM AUTHOR]

Based on the design concept of hybrid flexure hinge with large flexibility， an asymmetric hybrid flexure hinge with straight circle cycloid is proposed， and its mechanical characteristics are studied. Based on the bending theory of cantilever beam and Hooke's law under the micro element method， by selecting the appropriate integral variable and intermediate variable， the relatively simple calculation formula of rotational flexibility and tensile flexibility is obtained， and the general calculation formula of the maximum stress is given. The variation trend of rotational flexibility and maximum stress with parameters is discussed. The influence degree of structural parameters on rotational flexibility and maximum stress is compared. The results show that the maximum errors of the analytical expressions of rotational flexibility， tensile flexibility and maximum stress are within 5%， 7% and 5%， respectively. The rotational flexibility is inversely proportional to the elastic modulus， width and minimum thickness， and is directly proportional to the straight circle radius and arch height parameters， and is most sensitive to the change of the minimum thickness， followed by the width， and the arch height and straight circle radius are the weakest. The maximum stress is inversely proportional to the width， minimum thickness and the radius of the straight circle， and it is most sensitive to the change of the minimum thickness， followed by the width， and the radius of the straight circle is the weakest.

The objective of the present study was to investigate the mechanical indices of hoof horn and their association with length measurements and lesion score. The feet of 185 culled sows from three Greek farms (A: 57 sows; B: 64 sows; C: 64 sows) were used. A slice from the dorsal wall of each claw was used to assess by a three-point bending test the Young's modulus, yield stress and aximum stress values. The available data from a companion study (part 1) on the length measurements and lesion scores of the claws were used to reveal possible relationships. The Young's modulus values were significantly higher (p < 0.001 or p < 0.01 depending on location of claw) in the sows of farm C compared to those in sows of farms A and B and in sows of farm B compared to those in the sows of farm A. Yield and maximum stress values were significantly higher (p < 0.05 or p < 0.001 depending on the location of the claw) in the sows of farm C compared to those in the sows of farm A and in the sows of farm B compared to those in the sows of farm A. An increase in heel-sole length decreased all mechanical indices. Young's modulus and yield stress were associated with wall lesion severity while maximum stress with wall and heel lesion severity. Overall, we conclude that mechanical efficiency deteriorates as length and lesion score increases. [ABSTRACT FROM AUTHOR]

This study develops a new multi-material topology optimisation framework for design of periodic micro-composites with optimal functional performance and reduced stress concentration. First, multi-material topology optimisation is developed based on the alternating active phase algorithm and inverse homogenisation method with the sensitivity analysis derived for specific property objective i.e., negative Poisson's ratio (NPR) or maximum effective bulk modulus (EBM) and (p-norm macroscopic) stress objective. Then, the effects of initial material distribution and weight ratio (w1, w2 assigned to the property and stress objectives, respectively) are investigated, and the evaluation indices are also developed to obtain the optimal solution. Further, two cases related to the design of micro-composites for maximised either NPR or EBM with reduced maximum stress are performed. The results show that when designing the multi-material NPR micro-composites, the decrease of w1/w2 contributes to a general decease of both NPR and maximum stress. While in designing the maximum EBM, decreasing w1/w2 leads to the reduced maximum stress and simultaneously reduced EBM; hereby, a decision-making method as well as the proposed evaluation index are both applied and compared for acquiring the optimal result. This study provides new methods and solutions to multi-material micro-composites design for future industrial applications.

Intelligent manufacturing is a new mode and trend of sustainable manufacturing development. It optimizes the design and manufacturing process of products and greatly reduces the consumption of resources and energy by virtue of the huge potential of computer modeling and simulation and information communication technology. Under the background of intelligent manufacturing, intelligent bearing is proposed on the basis of traditional bearing products. Intelligent bearing is one of the research and development directions of high-end bearings at home and abroad. Embedded test technology is one of the research fields of intelligent bearings at present. Firstly, based on the finite element model, the structural design problems related to the integration of rolling bearing and sensor are studied. According to the load distribution of bearing, the optimal slot position of bearing is determined. Considering the influence of reducing the bearing capacity, the influence of axial and radial slot ways of bearing outer ring on the maximum deformation and stress of bearing outer ring is studied, and the bearing outer ring is analyzed The relationship between the maximum deformation, maximum stress and the groove size of the outer ring of the bearing is determined to provide the basis for the selection and design of the sensor module. Secondly, according to the friction moment formula, the total heat of the bearing is calculated. Based on the workbench, the temperature field cloud distribution model of the rolling bearing is established to analyze the changes of the speed, the radial load and the temperature of the inner and outer ring of the bearing Finally, according to the slot position and slot size, select the appropriate sensor and rolling bearing integration to achieve the real-time monitoring of the operation state of the bearing. [ABSTRACT FROM AUTHOR]

The situation of an off-center casing under non-uniform ground stress can occur in the process of drilling a salt-gypsum formation, and the related casing stress calculation has not yet been solved analytically. In addition, the experimental equipment in many cases cannot meet the actual conditions and the experimental cost is very high. These comprehensive factors cause the existing casing design to not meet the actual conditions and cause casing deformation, affecting the drilling operation in Tarim oil field. The finite element method is the only effective method to solve this problem at present, but the re-modelling process is time-consuming because of the changes in the parameters, such as the cement properties, casing centrality, and the casing size. In this article, an artificial intelligence method based on support vector machine (SVM) to predict the maximum stress of an off-center casing under non-uniform ground stress has been proposed. After a program based on a radial basis function (RBF)-support vector regression (SVR) (ε-SVR) model was established and validated, we constructed a data sample with a capacity of 120 by using the finite element method, which could meet the demand of the nine-factor ε-SVR model to predict the maximum stress of the casing. The results showed that the artificial intelligence prediction method proposed in this manuscript had satisfactory prediction accuracy and could be effectively used to predict the maximum stress of an off-center casing under complex downhole conditions. [ABSTRACT FROM AUTHOR]

So far, there are no results for research on the biomechanical parameters of giant miscanthus stalks taking into account both the influence of moisture content and the internode, from which the samples were taken. Therefore, the aim of the research was to comprehensively investigate the influence of the internode number (NrNod) and water content (MC) on the values of selected biomechanical parameters (modulus of elasticity and maximum stress) determined using various stress tests (three-point bending and compression along the fibers). The research was carried out for dry stalks of different humidities and for different internodes. The results obtained in this study proved that the independent variables of the water content and the internode number cause a statistically significant influence on the values of the examined biomechanical parameters of the miscanthus stem: the modulus of elasticity in compression, the maximum stress in compression, the modulus of elasticity in bending and the maximum stress in bending. The values of the modulus of elasticity (MOE) increase when increasing the NrNod. For individual internodes, MOE values are higher with a higher MC. The values of the maximum stress (σ) also increase when increasing the internode number. For individual internodes, the σ values are lower with a higher MC.

Based on an actual ultra-high voltage (UHV) substation, a finite element (FE) model for a high-voltage (HV) bushing, arrester, and down lead transmission line (DLTL) system was built using ANSYS software. The dynamic responses of the system under different seismic intensities were analyzed and compared with those of the corresponding single bushing and arrester. On this basis, the coupling vibration influence of the upper DLTL on the responses of the HV bushing and arrester is discussed. The results indicate that the DLTL adversely affects the responses of the HV bushing and arrester under seismic loading. As the seismic intensity increases, the structural displacements at the top of the HV bushing and arrester increase, accompanied by a reduction in the geometric length redundancy of the DLTL, resulting in a mutual pulling effect between the HV bushing and the arrester and the quick amplification of their respective dynamic responses in a nonlinear form. Under the action of an earthquake with a peak ground acceleration (PGA) of 0.4 g, the maximum stresses at the roots of the HV bushing and the arrester in the system separately increase by approximately 13.02% and 7.80% compared to the corresponding single HV bushing and the arrester. Overall, a geometric length redundancy of at least 200 mm in the DLTL in engineering design is recommended.

The flexible gear is the key parts of harmonic gear reducers,and its performance directly determine the overall condition of harmonic drives. In order to seek the basic law of influence of flexible gears wall thickness on its performance to make use of the law,the influences of flexible gears wall thickness on stress and deformation of the flexible gears are simulated and analyzed by ANSYS Workbench software under no-load and load conditions. The results show that,the maximum stress of the flexible gear increases and the maximum deformation decreases with the increase of the wall thickness under no-load condition. With the increase of the wall thickness,under the load condition,the maximum stress decreases overall and the maximum deformation decreases first and then tends to be gentle. Under the same wall thickness,with the increase of the load,the maximum stress and the maximum deformation both enhance and the load is more sensitive to the deformation in the places whose wall thickness are relatively thinner. Under the same conditions,the stress of flexible gear with bottom modification is smaller. This law can provide some reference for researchers.

Flameproof (Ex d) enclosures are constructed in such a way that an internal ignition of a flammable atmosphere will not be transmitted outside the enclosure and thereby preventing the ignition of surrounding flammables. The large Ex d enclosure was designed for gas group IIB explosive atmosphere with the help of MATLAB and ANSYS software and further a study of stress analysis due to internal pressure had been carried out on the plates and cover by keeping the thickness of body plate and cover constant. The study showed that stress was observed more in the center of the plate and reducing toward the edges of plates. The value of the length and breadth ratio (a/b) was found out with the help of the curve fitting method to calculate maximum stress (σmax) in the designed Ex d enclosure. The calculated maximum stress of all the plates was less than the simulated results, so the simulated results indicated that the designed enclosure is within the safety limit and suitable for hazardous area. [ABSTRACT FROM AUTHOR]

The non-interference uniform speed rope drilling coring device is a tool for investigating samples of submarine underground leakage hydrate rock formations. In the process of coring, the penetration resistance of the shoe is large, and the rock stratum is disturbed, which results in disturbance of the rock sample's original state. In order to solve this problem, the standard core diameter is ∅72 mm and the length is the length of a single cylinder. For example, a drilling coring device with a working outer diameter d not more than 90 mm is used to optimize the size and structure of the shoe. To ensure the strength of the tube shoe, the related dimensions of the shoe were optimized using finite element analysis software, and the structure of the shoe was improved based on the optimized dimensions. The results of the size optimization are: á = 20 °, 11 = 13mm, and ä = 1.5mm: the structural improvement results are: the front cone surface at the lower end of the rube shoe is changed to a regular mesa, and the number of regular mesa sides is 32. The LS-DYNA dynamic simulation results show that the penetration resistance of the tube shoe after size optimization and structure improvement is significantly reduced, so the disturbance of the drilling and coring device to the rock formation is also reduced, and the quality of the sample is improved. [ABSTRACT FROM AUTHOR]

This article investigates analytical methods for calculating mechanical stress on the rotor of Interior Permanent-Magnet Synchronous Machines (IPMSMs). First, two existing analytical methods for calculating the stress on rotor iron bridges were investigated using a flat-type IPMSM model. The calculations of centroid radii required by these methods were simplified by taking advantage of the symmetry. Then, an accurate function of the stress concentration factor (SCF) was developed to calculate the maximum mechanical stress (MMS) on the iron bridge from its reference stress. The trends of SCF and MMS changing with geometrical parameters were obtained during the statistical analysis of SCF. Using the proposed analytical method, MMS on the bilateral iron bridges of both flat- and V-type IPMSMs can be calculated accurately. Finite element analysis (FEA) shows that the proposed method has improved accuracy and generality in calculations of the MMS. The reliability of the FEA model and the proposed analytical method were further investigated in a plastic deformation experiment. Based on the experimental results, the limits of the stress models, selection of the failure criteria, and safety factor were discussed for high-speed IPMSM design. [ABSTRACT FROM AUTHOR]

The effect of heat flux (HF) is crucial for understanding the behavior of materials, particularly in terms of crack propagation. HF can induce thermal stresses that accelerate crack growth, which can compromise the structural integrity and safety of materials. However, by studying the effect of HF, we can gain insights into the mechanisms that lead to crack initiation and growth. The importance of this study lies in its contribution to understanding the impact of external HF (EHF) on the cracking behavior of Aluminum nanoplates. For this purpose, EHF with 0.01, 0.02, 0.03, 0.05, and 0.1 W/m2 are added to the initial structure. By inserting EHF into the modeled samples, the atomic evolution of them is investigated. This study was performed using LAMMPS software and molecular dynamics (MD) simulation. Numerically, the maximum velocity of atoms increased from 4.81187 Å/ps to 4.81236 Å/ps as the EHF rose from 0.01 W/m2 to 0.1 W/m2. The maximum stress of samples increases from 151.689 GPa to 151.712 GPa by the EHF ratio enlarging. Finally, the crack length reaches to the maximum value (33.492 Å) by the EHF ratio set to 0.03 W/m2.By investigating the atomic evolution and crack growth process under different EHF values, the study provides valuable insights into the underlying mechanisms and thermal effects that influence crack propagation in these materials. This knowledge can be utilized to optimize the design and performance of aluminum nanoplates in practical applications, such as in the development of more robust and reliable structural components or devices. [ABSTRACT FROM AUTHOR]

The objective of the present study was to investigate the mechanical indices of hoof horn and their association with length measurements and lesion score. The feet of 185 culled sows from three Greek farms (A: 57 sows; B: 64 sows; C: 64 sows) were used. A slice from the dorsal wall of each claw was used to assess by a three-point bending test the Young’s modulus, yield stress and aximum stress values. The available data from a companion study (part 1) on the length measurements and lesion scores of the claws were used to reveal possible relationships. The Young’s modulus values were significantly higher (p < 0.001 or p < 0.01 depending on location of claw) in the sows of farm C compared to those in sows of farms A and B and in sows of farm B compared to those in the sows of farm A. Yield and maximum stress values were significantly higher (p < 0.05 or p < 0.001 depending on the location of the claw) in the sows of farm C compared to those in the sows of farm A and in the sows of farm B compared to those in the sows of farm A. An increase in heel-sole length decreased all mechanical indices. Young’s modulus and yield stress were associated with wall lesion severity while maximum stress with wall and heel lesion severity. Overall, we conclude that mechanical efficiency deteriorates as length and lesion score increases.

This paper provides a numerical analysis of selected parameters of fracture mechanics for double-edge notched specimens in tension, DEN(T), under plane strain conditions. The analysis was performed using the elastic-plastic material model. The study involved determining the stress distribution near the crack tip for both small and large deformations. The limit load solution was verified. The J -integral, the crack tip opening displacement, and the load line displacement were determined using the numerical method to propose the new hybrid solutions for calculating these parameters. The investigations also aimed to identify the influence of the plate geometry and the material characteristics on the parameters under consideration. This paper is a continuation of the author’s previous studies and simulations in the field of elastic-plastic fracture mechanics [4, 6, 16, 17, 31].

In order to meet the requirements of strength and service life of steel belt in the transmission process,the mechanical property of the transmission steel belt is analyzed,and comes to the conclusion that the main reasons for the changes of the steel belt stress are the initial tension,the thickness of the steel belt,roller diameter,and finds out where the maximum stress may occur. At the same time,based on theory,the kinetic and dynamic characteristics of steel belt are analyzed. Finally,by using the Recur Dyn software,steel belt is stimulated,the relevant dynamics and kinematics curves are got and compared with the theoretical analysis,a reference for the design and calculation of steel belt is provided.