最新刊期
卷 47 ， 期 4 ， 2025
- 摘要：The bearing section of the work roll neck often suffers burnout failure due to bearing seizure, and additive manufacturing is usually used in the field to repair it.Life prediction of the repaired roll neck is the key to predict the safe service of the work roll in the field production and carry out overhaul，but there is a lack of research on the related issues.In view of the above problems, the stress analysis and multi-axis life prediction of the working roll neck bearing section of the four-high mill were carried out.Based on the SIMS model and the influence function method, the rolling force and the stress between the rolls were calculated.The moment balance equation of the roll neck end was established in the bearing section, and the bending stress model of the roll neck bearing section was established.The deformation resistance was regarded as the plastic deformation energy per unit volume to calculate the rolling torque in the deformation zone, and the torsional shear stress model of the roll neck bearing section was established.Using the first strength theory, the equivalent stress was obtained by combining the bending stress and the torsional shear stress.On the basis of proving the calculation accuracy of the model, the multi-axis fatigue model was used to predict the fatigue life of the roll neck bearing section, and compared with the service life of the actual roll in the production line.The results show that the stress calculation model of the working roll neck bearing section of the four-high mill is in line with the actual stress state of the roll neck.The error between the expected service life predicted by the theoretical model and the actual service life is less than 20%, which meets the actual engineering error requirements.关键词：Four-high mill;Work roll neck bearing section;Multi-axis fatigue;Life prediction10|3|0更新时间：2025-04-25
- 摘要：In view of the difficulty of obtaining durability test specifications for axle components, a method of constructing driving load of the front axle dynamic model was proposed to provide the input for system-level bench test and life verification of front axle components. The life of front axle was obtained based on the whole vehicle dynamics model and the measured road load, and the useful information and life prediction results in the above process were employed to guide the construction of driving load applied on front axle. Firstly, the frequency band of the measured six-component forces at the wheel center was adjusted. Then, with the goal of minimizing the difference between the damage/life of the front axle and the reference value under each working condition, the adjustment coefficient of the amplitude of the three-way forces at the wheel center was optimized by combining the response surface method and genetic algorithm. The optimized three-way forces at the wheel center and the other three-way torques constituted the driving signal of the front axle model. The results show that the constructed wheel center drive signal is used to simulate the dynamic load of the front axle model. The life of the front axle, the failure sequence of risk points and the damage contribution ratio of various road conditions to dangerous points are obtained and in good agreement with the reference results, which verified the effectiveness of the proposed method and provided reference for the drive signal construction and component life evaluation of system-level bench durability test. Finally, the damage distribution of the front axle can be consistent with the reference results by modifying the main damage load of the shaft tube.关键词：Dynamics model of front axle;Life of front axle;Surface response method;Dynamic load simulation;Bench test8|0|0更新时间：2025-04-25
- 摘要：Aiming at the storage life evaluation of photodetectors, a new evaluation method for multi-parameter competitive failure storage life assessment based on Monte-Carlo method was proposed. This method comprehensively considered whether the key performance parameters of the sample have deteriorated or improved trend. Firstly, the optimal degradation model with a single parameter was selected by performance degradation modeling, so that the pseudo-life of the sample with increasing degradation trend was calculated according to the failure threshold, and the pseudo-life was regarded as the right-censored data for the sample with decreasing degradation trend. Furthermore, the optimal distribution of a single performance parameter was selected based on the pseudo-life data combined with the expectation maximization(EM) algorithm, and then the competitive failure evaluation of multi-parameters was carried out by Monte-Carlo sampling method. According to the case analysis of the photodetector storage, the feasibility of this method was verified.关键词：Multi-parameter performance degradation;Competitive failure;Storage life;Expectation maximization algorithm;Monte-Carlo sampling8|0|0更新时间：2025-04-25
- 摘要：The mechanical response of external rotor direct drive generator under time-varying loads is analyzed theoretically, calculated by simulation and verified by test. Firstly, the source of magnetic pull of the rotor core of the external rotor generator and its variation with load were analyzed. The expression of magnetic pull of the rotor and the characteristics of time and space order were determined. The basic vibration model of the external rotor core was analyzed, and the basic vibration equation of the external rotor core was determined. Then the simulation model of the external rotor generator was established, and the spatiotemporal order characteristics of the magnetic pull and the typical daily variation rule with time were obtained. The magnetic pull density obtained from the electromagnetic field was used as the input load to guide the structure field. The magnetic-solid coupling simulation was carried out, and the deformation and stress distribution and noise response of the external rotor core were calculated and analyzed. Finally, a simulation example of a 13 kW external rotor direct-drive generator proved the correctness of the analysis and simulation. The results of the study determined the time-varying load on the outer rotor core and its mechanical response distribution. It is found that the time and position of the rotor core should be tested emphatically when the generator is running. Noise characteristics under time-varying loads are also analyzed. The analysis provides reference for the maintenance and design of the generator.关键词：External rotor direct drive permanent magnet synchronous generator;Mechanical response;Magnetic pull;Time-varying load;Electromagnetic noise5|0|0更新时间：2025-04-25
- 摘要：The gearbox of wind turbine is in the complex environment such as random wind load for a long time, and the gear contact fatigue becomes a key factor limiting the stability and reliability of wind turbine equipment. The research on the gear contact damage evolution mechanism is faced with difficulties such as complex stress states, damage anisotropy and failure modeling. Material configurational force theory can describe the effect of defect configurational change on the free energy of materials and can be used to predict the damage and failure behavior of materials. A wind turbine gear contact damage model was constructed based on this theory. The gear contact interface stress field simulation analysis was carried out for the key bearing area of gear contact, and the gear contact damage evolution process under contact load was simulated. The results show that the configurational force theory damage model can effectively simulate the contact damage phenomenon of gear and explain the pitting and spalling of gear surfaces. It has significance to predict contact fatigue life of gears accurately.关键词：Wind turbine gear;Gear contact;Configurational force;Interfacial stress;Damage evolution34|67|0更新时间：2025-04-25
- 摘要：The traditional Paris formula ignores the influence of various uncertain factors in the crack growth process, which leads to a big difference between the predicted crack growth process and the real crack growth process. In order to improve the prediction accuracy of fatigue crack growth, a fatigue crack growth prediction method based on the improved particle swarm optimization particle filtering (IPSO-PF) algorithm was proposed. Firstly, based on the framework of the particle filtering (PF) algorithm, the particle swarm optimization (PSO) algorithm was used to optimize some particles based on the updated observation information， keeping the state of particles with large weights unchanged, and particles with small weights tend to high likelihood region, and IPSO-PF algorithm was designed. Then， combining IPSO-PF algorithm with Paris formula, a fatigue crack growth prediction model based on Paris formula and IPSO-PF algorithm was constructed. Finally, the validity of the model was verified by using the open 2024-T351 aluminum alloy data set. The results show that compared with the traditional PF algorithm, IPSO-PF algorithm can improve the diversity of particles. The prediction error of the crack growth prediction model based on IPSO-PF algorithm is 2.6%, which is better than 9.2% based on PF algorithm.关键词：Fatigue crack;Crack growth prediction;Particle filtering;Particle swarm optimization;Algorithm optimization5|1|0更新时间：2025-04-25
- 摘要：Taking a 1.5 MW wind turbine tower with different initial crack lengths as the research object, vertical and horizontal earthquake loads with four earthquake intensities and three actual earthquakes were applied, respectively. The influence of vertical and horizontal earthquake loads on the strain field at the crack tip of the wind turbine tower was studied and compared. The results indicate that both under vertical and horizontal earthquake loads, the equivalen plastic strain area at the crack tip increases with the increase of earthquake intensity, but under horizontal earthquake loads, the equivalent plastic strain area at the crack tip increases more rapidly. Under earthquake intensities of Ⅵ and Ⅶ, the impact of vertical earthquake loads is greater than that of horizontal earthquake loads. As the earthquake intensity increases, the impact of horizontal earthquake loads increases sharply under earthquake intensities of Ⅷ and Ⅸ, and far exceeding the impact of vertical earthquake loads. The impact of vertical actual earthquake load on the crack tip equivalent plastic strain area is related to the magnitude and earthquake acceleration time-history curve, while the impact of horizontal actual earthquake load on the crack tip equivalent plastic strain area is related to the earthquake acceleration time-history curve.关键词：Vertical earthquake load;Horizontal earthquake load;Earthquake intensity;Actual earthquak;Crack tip strain field;Wind turbine tower5|0|0更新时间：2025-04-25
- 摘要：In order to investigate the compression damage evolution of carbon fiber laminates with wrinkles and accurately predict the mechanical behavior of damage initiation and propagation, a progressive damage finite element model was proposed based on three-dimensional elastic theory by employing a spatial decomposition of damage variables method to establish the damage constitutive relation. Firstly, the maximum stress and Puck failure criteria were used to predict the intralaminar damage initiation, and the damage variables were calculated in combination with the mixed-mode damage evolution law. Secondly, based on the physical meaning of the damage variables, a spatial decomposition was carried out in the fracture plane coordinate system, and the damage constitutive relation was derived by substituting the damage stiffness matrix. Then in order to predict the interlaminar stress state and damage behavior of laminates, a cohesive zone model with a bilinear traction-separation law was adopted. Finally the corresponding Vumat subroutine was developed and implemented in Abaqus software for the numerical simulation analysis of quasi-static compression loading at 0.25 mm/min.The stress-displacement curves and damage distribution of laminates predicted by the finite element model are in good agreement with test results. The proposed calculation method is simple and direct for determining true stress, making it convenient for analyzing and identifying the damage location and damage evolution of composite laminates with wrinkles.关键词：Carbon fibre reinforced composite;Damage constitutive;Progressive damage model;Cohesive zone model;Wrinkling defect5|0|0更新时间：2025-04-25
- 摘要：In order to simulate the crack propagation by corrosion fatigue, a coupled peridynamics corrosion-fatigue fracture model was proposed and applied to the simulation and analysis of crack propagation in A7N01P-T4 aluminum alloy. In this model, the interaction of hydrogen and stress was used to reflect the synergy between the two mechanisms of anodic dissolution and hydrogen cracking in corrosion, and the corrosion solution step and the mechanical solution step were coupled when quantifying the fracture behavior of the material due to corrosion. Since hydrogen reduces the plasticity of the material and brittle fracture occurs, a bonded peridynamics theory suitable for simulating isotropic brittle damage was used, and the relation between near-field force and elongation was described using an intrinsic force function for quasi-brittle materials that incorporates both linear and nonlinear mechanical behavior. The feasibility of the model is verified by comparing the simulation results with the test results of A7N01P-T4 aluminum alloy in 3.5% NaCl solution, and it is found that the results are in good agreement between them.关键词：Peridynamics theory;Constitutive equation;Corrosion fatigue;Anodic dissolution;Crack propagation8|0|0更新时间：2025-04-25
- 摘要：Coatings have extensively been used to the surfaces of critical components to enhance their service life, and the research on mechanical properties of coatings is essential for advancing this technology. TiAlN/Ti and TiN/Ti multilayer coatings were prepared on aluminum matrix composite surfaces by using the vacuum ion beam sputtering technique. The microstructure, phase composition， and mechanical properties of the coatings were characterized and analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and nanoindentor. The dimensionless function correlation between mechanical properties of material with multilayer coatings and the loading/unloading parameters of nanoindentation was derived based on dimension analysis theory, and its explicit expression was determined in conjunction with the finite element simulation method. By establishing a nanoindentation simulation model for the multilayer coating, the impact of residual compressive stress on the tensile properties of the multilayer coating was analyzed. The results indicate that residual compressive stress can enhance the yield strength of the multilayer coatings. The residual compressive stress of TiN/Ti multilayer coating is -564 MPa, increasing the yield strength by 31.25%. Similarly, the residual compressive stress of TiAlN/Ti multilayer coating is -871 MPa, resulting in a 50% increase in yield strength. An important theoretical and test basis is proposed for quantitative analysis of the factors influencing the mechanical properties of coatings.关键词：Nano-indentation;Multilayer coating;Residual compressive stress;Finite element;Inversion analysis7|0|0更新时间：2025-04-25
- 摘要：The fracturing pump plunger seal pair is one of the components most prone to failure at the hydraulic end of the fracturing pump due to its long-term operation under variable load，reciprocal friction and high pressure, and acidic fracturing fluid. To study the influence of interference magnitude, medium pressure, etc.on the sealing performance of V-shaped sealing ring, the assembly process of V-shaped sealing ring was simulated by using automatic shrinkage fit, the actual fluid pressure action condition of the V-shaped sealing ring was simulated based on fluid pressure penetration, and the finite element model of V-shaped sealing ring was established. Under quasi-static and dynamic sealing, the maximum Mises stress and the variation law of contact pressure of the V-shaped sealing ring were analyzed. A two-stage differential pressure plunger seal structure was proposed, and the sealing performance analysis of the structure was carried out.The results show that the maximum contact pressure of the seals all appear in the V-shaped sealing ring near the high-pressure fluid side, and the maximum stress is mainly in the lip and shoulder of the V-shaped sealing ring in contact with the support ring and press ring, the V-shaped sealing ring is more likely to fail on the side in contact with the plunger. The use of two-stage differential pressure plunger seal can effectively reduce the Mises stress, shear stress, and friction between the V-shaped sealing ring and the plunger, which can extend the working life of the fracturing pump plunger seal and improve the reliability and economy of the fracturing operation.关键词：V-shaped sealing ring;Interference assembly;Fluid pressure penetration;Structural design;Sealing performance6|0|0更新时间：2025-04-25
- 摘要：Sandwich structures composed of PET foam core and aluminium alloy panel were taken as reserch object. In the process of fabricating sandwich structures, four types of core materials were employed. Firstly, untreated PET foam core and PET foam cores subjected to subtractive process treatment (unidirectional slotting, bidirectional slotting，and punching). Secondly, the peel resistance performance between the aluminium alloy panel and PET foam core was tested through the drum peel test, while the influence of material subtractive process on shear performance of the sandwich structures was evaluated through the pure shear test. Finally, the peel and shear failure modes, load-displacement responses, and peel and shear strengths of the structures were analysed.The results show that the peel strength between the panel and PET foam core is improved by 48.31%, 32.29%, and 16.67% respectively, compared with the untreated structure, by using bidirectional slotting, unidirectional slotting and punching processes. Although the three processing techniques cause damage to the PET foam core, they actually increase respectively the shear yield strength of the sandwich structures by 3.12%, 3.90%, and 2.92%, compared to the untreated structure.关键词：PET foam sandwich;Core material subtractive treatment;Drum peeling;Peeling performance;Shear test;Shear performance6|0|0更新时间：2025-04-25
·Fatigue·Damage·Fracture·Failure Analysis·
- 摘要：The relative curvature of the spur gear mesh point is one of the key geometric parameters of the tooth profile, which has a significant impact on the stress distribution and mesh stiffness of the gear. Starting from the relevant research on constant relative curvature (CRC) gears, three types of non-involute spur gear tooth profiles were constructed based on the relative curvature control strategy considering the time-varying mesh characteristics of gears, and the mesh simulation of gear pairs was implemented. The influence of relative curvature control on the maximum contact stress, maximum bending stress, and mesh stiffness of gears was analyzed. The effectiveness of the control strategy was verified. This work provides some reference for the design of spur gears based on the relative curvature control.关键词：Relative curvature;Spur gear design;Mesh process;Stress analysis6|1|0更新时间：2025-04-25
- 摘要：Due to the similarity between the internal structure of wind turbine blades and plant leaves, a new type of bionic leaf vein structural distribution was proposed, along with an entire composite blade layup program based on the bionic method of applying the mid-axis morphology of plant blades to 5 MW wind turbine blades. The modal analysis and static analysis of the new bionic vein blade were performed using the fluid-solid coupling method. The results show that the first six-order of the nature frequency of the bionic blade are improved in comparison to the traditional layup blade and are difficult to resonate, as well as its torsion resistance. Under the extreme wind load of 50 m/s, the displacement of the bionic blade’s tip is significantly smaller than that of the traditional blade, and the distribution of the strain and the distribution of the shear stress are more uniform than those of the traditional layup blade, but the maximum value of shear stress rises.关键词：Wind turbine blade;Composite materials;Leaf vein;Bionics;Layer design6|0|0更新时间：2025-04-25
- 摘要：At present, the research on supersonic civil aircraft wings mainly focuses on the low sonic boom design and supersonic drag reduction technologies. There are relatively few studies on the wing structural design. Therefore, a multi-level optimization method for the wing structural design in the preliminary design stage of supersonic civil aircrafts was proposed. It included the parametric modeling of the wing structural layout, the automatic generation of the finite element model for the structural size optimization, construction and training of a surrogate model for the deep neural network. And the optimization was solved based on the deep neural network. The analysis results show that the proposed optimization strategy could quickly design the wing structure of the supersonic civil aircraft. The deep neural network model has higher prediction accuracy than the traditional surrogate model. Thus, the proposed approach can improve the efficiency of the preliminary design for wing structure.关键词：Supersonic civil aircraft;Parameterization;Deep neural network;Surrogate model;Structural design6|1|0更新时间：2025-04-25
- 摘要：Impulse current under short-circuit condition is the key factor for the structural reliability of the testing transformer. Therefore, the structural reliability analysis model of transformers was proposed based on the probability density evolution theory. Firstly, the basic principle of probability density evolution theory was introduced, and the analysis method of electromagnetic force field for windings was given considering the coupling effects of magnetic and electric fields. On the basis， the numerical analysis model of transformers structure was constructed by using the Abaqus software finite element analysis method. Taking an AGF 20 kV testing transformer as an example, the above model was validated. The longitudinal Mises stress of windings was chosen as the control variable, and the stress distribution and probability density evolution characteristics were given. Then, the structural reliability index was calculated, and the extreme mechanical response and the corresponding distribution zones of windings and iron cores were discussed. The results show that the stress of windings increases significantly under the action of short-circuit impulse current. The maximum value of windings’stress reaches 82% of the threshold, and plays the key role in structural reliability, the increase of impedance has obvious influence on the reliability of transformers.关键词：Testing transformer;Structural reliability;Winding;Probability density evolution;Short-circuit7|0|0更新时间：2025-04-25
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Analysis and optimization of heat dissipation of gas mainframe case based on field synergy principle
摘要：In order to ensure the safe and stable operation of gas turbine units, and grasp the heat transfer mechanism of the ventilation system of the mainframe housing, a study on the ventilation and heat dissipation of the main engine box of gas turbine units was carried out. Based on the principle of field synergy, the internal flow field, temperature field and heat dissipation performance of key equipments in the mainframe cabinet were analysed, and an optimized scheme for adding a flow-guiding device was proposed. The results show that the volume of the high-temperature area inside the mainframe housing is 7.6%, mainly concentrated near the gas turbine shaft component, which is the main heat source inside the mainframe housing, with an average external surface temperature of 86.94 - 摘要：In order to improve the load-bearing efficiency of the stiffened conical shell in large launch vehicle, the lightweight design of the stiffened conical shell was carried out via a data-driven multi-fidelity approximate modeling optimization method.Aiming at the problems such as low efficiency and insufficient accuracy of the single fidelity approximate modeling optimization method, a data-driven multi-fidelity approximate modeling optimization framework was built based on variable-fidelity expected improvement (VF-EI) point criterion，and accordingly the optimization design of stiffened conical shell structure was carried out.Based on the finite element models of stiffened conical shells with different mesh sizes, a Co-Kriging multi-fidelity approximate model for the collapse load of stiffened conical shells was established.In the optimization iteration, multi-fidelity sampling points were generated by using VF-EI point criterion, and the global and local approximation accuracy of Co-Kriging multi-fidelity approximation model was improved sequently.Moreover, the optimization efficiency and accuracy of the proposed method were demonstrated by comparing with radial basis function approximation model and Kriging model. Besides, 11.5% weight reduction of the optimized stiffened conical shell structure is obtained compared with the initial design, which has certain engineering application value.关键词：Stiffened conical shell;Multi-fidelity approximate modeling;Sequence approximate optimization method;Lightweight design;VF-EI point criterion6|0|0更新时间：2025-04-25
·Optimization·Reliability·
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