最新刊期
卷 47 ， 期 3 ， 2025
- 摘要：Dichloromethane solution was introduced as the corrosion medium by the liquid drop method.Based on the regular quadrilateral, regular hexagon and concave structures with different porosities，the effects of different corrosion cycles and areas on the porous structural mechanical properties of polylactic acid (PLA) were analyzed by comparing with the finite element simulation results.The results show that concave porous structure plate is the least affected by the corrosion cycle, while the other two structures are affected by it depending on the size of the porosity.The hexagonal structure with a porosity of 72% has the weakest corrosion defect bearing capacity, while the concave structure has the strongest bearing capacity.The regular quadrilateral structure with a porosity of 54% is most affected by the single cell corrosion.The corrosion bearing capacity of the expanded area of a single cell in a regular hexagonal structure is weaker than that of a single cell, while the corrosion bearing capacity of the expanded area of a single cell in a regular quadrilateral structure is stronger than that of a single cell.关键词：Corrosion;Dichloromethane solution;Polylactic acid porous structure;Mechanical property2|0|0更新时间：2025-04-03
- 摘要：High-speed machining technology by improving the cutting speed and feed rate to improve the material cutting rate, machining accuracy and machining quality, is one of the main ways of modern processing. Therefore, to ensure the stability of high-speed machining is the basis of application of high-speed machining. Firstly, based on the traditional stability analysis, the influence of feed rate on the static cutting thickness was further considered, the stability model related to feed rate and radial cutting depth ratio of tool was established, and the stability of high-speed milling was analyzed by combining stability variance ratio. Secondly, based on the single factor variable feed rate test, a filter was designed to filter the frequency component of the spindle speed. The variance ratio between the filtered signal sequence and the original signal sequence was used to analyze the milling stability changes of the continuous variable axial depth test, and the validity of the analysis method considering the feed rate to affect the stability of high-speed milling was verified. The results show that the proposed method can determine milling stability more accurately for high-speed machining with small radial cutting depth. And the axial cutting depth of unstable cutting limit changes slightly with the increase of feed rate, and the feed rate will aggravate the instability of milling system.关键词：Feed rate;Radial cutting depth;Milling stability;Static cutting thickness;Stability identification2|0|0更新时间：2025-04-03
- 摘要：In order to eliminate the restriction of the return spring stiffness on the power generation and system reliability of the energy harvesting speed bump with the full wave mechanical rectifier, a dual-speed bump energy harvester (DBEH)based on the half-wave mechanical rectifier was proposed. The device utilized a mechanical transmission module to convert the downward linear movement of two speed bumps, driven by wheels, into the one-way rotary movement of a single generator shaft, thereby converting mechanical energy into electrical energy. The unidirectional motion conversion reduced the demand for the load of the return spring. The theoretical model of the wheel excitation and speed bump dynamics was established and verified by road tests. Based on the theoretical model, the power generation performance of DBEH was studied by numerical simulation. The research results indicate that the root mean square (RMS) power and output electrical energy of the system increase with the increase of external excitation amplitude and the decrease of the spring stiffness. When the load resistance value is 7-9 Ω, the output performance of the system is optimal. Compared to reducing the gear radius, increasing the speed of the gearbox has a more significant impact on the improvement of system output. A small inertia flywheel can effectively improve the system’s capture of the mechanical energy and the conversion rate from the mechanical energy to the electrical energy.关键词：Half-wave mechanical rectifier;One-way clutch;Energy harvesting speed bump;Energy harvesting on road;Generation performance2|0|0更新时间：2025-04-03
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Study on influence of cross section shape evolution on crashworthiness of multicellular square tubes
摘要：Taking multicellular square tubes as the research object, the influence of the evolution of cross section shape on the energy absorption of the structure of multicellular square tubes was studied by using the verified finite element model. The results show that, under the same mass conditions, the multicellular tubes with the best energy absorption k=0.25 increased by 26.34% compared with those with the worst energy absorption k=0.40. Under the same wall thickness, the energy absorption with k=0.25 and the specific energy absorption of the multicellular tubes were 311.69% and 73.80% higher respectively than that of the ones with k=0, and the crushing force efficiency was increased by 52.51%. Finally, the parametric study of shape coefficient and wall thickness on the structural crashworthiness was carried out systematically. The research results can provide a reference for innovative design of multicellular square tubes.关键词：Multicellular square tube;Shape evolution;Crashworthiness;Energy absorption2|0|0更新时间：2025-04-03 - 摘要：To explore the impact of key parameters of brake pads on the dynamics characteristics of the braking system, the test research based on a friction testing machine with a slider-disc structure was conducted.The test research of the impact of key parameters of brake pads (rotation speed, pressure, mass, braking radius, etc.) and the braking environment (dry friction, wetness, sand) on the stability of the braking system was carried out. At the same time, a dynamics model of the brake pad braking system was established，compared with test results using the mathematical tool of autocorrelation coefficient. The results show that the key parameters of brake pads have a significant impact on the dynamics characteristics of the braking system; under different conditions of brake pad mass, tribological parameters, brake pad radius, and braking environment; the chaotic characteristics of the braking friction force signal show a trend of expansion or contraction; the chaotic vibration can be suppressed by adjusting the key parameters of brake pads. This study can provide reference for optimizing the braking strategy and reducing noise and vibration in brake pad systems.关键词：Braking system;Friction vibration;Test analysis;Chaos characteristic;Friction model2|0|0更新时间：2025-04-03
- 摘要：In order to construct a bone scaffold structure with good biological properties, P-type, FRD-type homogeneous multi-porous scaffolds and P&FRD gradient multi-porous scaffolds with different porosities and unit cell scales were designed based on the triply periodic minimal surface（TPMS）.The effects of unit cell types, porosities and unit cell scales on the mechanical and biological properties of TPMS multi-porous scaffolds were investigated by tests and finite element simulation.The results show that the internal pores of homogeneous and gradient multi-porous scaffolds based on TPMS have good connectivity.The mechanical properties of multi-porous scaffolds decrease with the increase of porosity, but the permeability increases with the increase of porosity.Increasing the unit cell scale can significantly improve the permeability of multi-porous scaffolds.The permeability of the gradient multi-porous scaffold is also affected by the seepage direction.The gradient multi-porous scaffolds can synthesize the performance characteristics of each homogeneous unit cell structure, and show different mechanical and biological properties in different regions of the scaffold, which is closer to the structure and biological properties of human bone.关键词：Triply periodic minimal surface;Gradient multi-porous scaffold;Mechanical property;Permeability2|0|0更新时间：2025-04-03
- 摘要：To solve the problems of high-power downstream belt conveyors in large inclination angles, high belt speed conditions which are very prone to flying cars and belt breakage, a kind of disk-type adjustable permanent magnet damping roller device was put forward by adjusting the size of the area of engagement between the permanent magnet and the coil to realize the braking adjustment. The Maxwell software was used to study the transient magnetic density distribution law of the disk-type permanent magnet damping device under stable conditions and the changing law of damping torque by different air gap thicknesses, and the test bench was built for test verification. The results show that with the increase of the air gap thickness, the magnetic density gradually increases, up to 2.1 T. The damping moment increase when air gap thickness is from 1 mm to 2 mm, the damping moment decrease when from 2 mm to 3.5 mm. The research can provide data support for improving and optimizing high-power downstream belt conveyors.关键词：Belt conveyor;Damping roller;Maxwell software;Damping moment;Finite element analysis2|0|0更新时间：2025-04-03
- 摘要：In order to simulate the shot peening process and realize the rapid prediction of the shot peening effect, a random multi-shot pellet shot peening strengthening model was established based on Abaqus software using the discrete element method-finite element method (DEM-FEM) coupling, and the TC4 titanium alloy was used as the research object to carry out the shot peening strengthening test to verify the accuracy of the coupling model. The Box-Behnken design (BBD) method was used to design a three-factor and three-level shot peening simulation test scheme for the three process parameters of projectile size, shot peening speed and shot peening coverage.The surface residual stress value and surface roughness value were obtained by simulation analysis, and the numerical fitting was carried out by Design-Expert software. Finally, the function models between the shot peening process parameters and the surface residual stress or surface roughness were obtained, the interaction between the three factors of projectile size，shot peening speed and shot peening coverage was analyzed by the response surface method, and the influence law of shot peening strengthening effect was analyzed.The results show that the error between the results of the response surface prediction model and the simulation calculation results is less than 5%, the established response surface prediction model has high approximate accuracy and reliability，and the effective prediction of shot peening effect can be achieved by using this model.关键词：Shot peening;Response surface;DEM-FEM coupling;Box-Behnken design2|0|0更新时间：2025-04-03
·Experimental Research·Testing Technology·
- 摘要：To investigate the vibration performance of RV reducers and analyze the fault identification, the torsional vibration test bench for RV reducers was built.Based on the mechanical structure and transmission principles of RV reducers, the vibration frequencies under different operating conditions were calculated.The vibration signal of RV reducers of superior and inferior products was collected, and the acceleration signal of the torsional vibration under different speeds and swerves was collected.The torsional vibration signals were decomposed using the variational mode decomposition (VMD) to obtain the intrinsic mode function (IMF).The results demonstrate a high correlation between the extracted IMF features obtained through VMD and the vibration frequencies observed during the operation of RV reducers.Furthermore, by comparing the spectrum of IMF, the reasons behind the abnormal vibration in inferior RV reducers were identified.Ultimately, it is determined that the abnormal vibration in inferior RV reducers were caused by the excitation from the interaction between the auto rotation of the planetary gear and the crankshaft or the revolution of the cycloid gear.This study provides valuable insights for enterprises aiming to improve the transmission accuracy and product quality of RV reducers.关键词：Variational mode decomposition;RV reducer;Torsional vibration;Vibrational frequency2|0|0更新时间：2025-04-03
- 摘要：A single-degree-of-freedom mechanical collision vibration system model with nonlinear terms and unilateral new nonlinear constraints was studied.The dynamics characteristics of the p/1 periodic motion of the system under low-frequency excitation were analyzed by using the variable-step fourth-order Runge-Kutta numerical algorithm and multi-parameter co-simulation.And the frequency hysteresis characteristics of the grazing bifurcation and saddle-node bifurcation in the p/1 periodic motion were analyzed.It was found that two different motions will exist at the same time，revealing the irreversibility of the transition between adjacent periodic motions.Finally, the influence of the change of the gap on the multi-state coexistence region of the system was studied.As the gap increases, the coexistence region of partial periodic motion decreases and transits to the low-frequency region.关键词：Nonlinear constraint;Bifurcation;Multi-parameter coordination;Attractors coexistence2|0|0更新时间：2025-04-03
- 摘要：In order to solve the problem of the accuracy of the random vibration transmissibility calculation of airborne electronic equipment, the basic STEINBERG sinusoidal vibration transmissibility model and the IRVINE random vibration transmissibility model were firstly verified through tests, and it was found that there was room for improvement in the accuracy of the IRVINE random vibration transmissibility model. Therefore, on the basis of the "Three-interval method", the effects of
- 摘要：In practical engineering, gearboxes are subject to complex and variable operating environments, which hinder the ability of a single vibration signal to accurately and effectively represent fault information under different working conditions. To address this issue, a gearbox fault diagnosis method for variable working conditions based on weighted subdomain adaptive adversarial networks was proposed. Initially, a multi-source heterogeneous signal fusion strategy was employed to transform vibration signal spectrograms, current signal Gramian matrices, and infrared thermograms into a multi-channel dataset, offering diverse perspectives on gearbox operational states. Subsequently, a self-calibrated convolutions network (SCNet) incorporating an efficient channel attention (ECA) mechanism acted as a feature extractor, dynamically adjusting the interactions and dependencies between multi-source heterogeneous signals to balance the scale differences between the source and target domain heterogeneous data. Concurrently, during adversarial training of the feature extractor and domain discriminator, maximum mean discrepancy (MMD) and linear discriminant analysis (LDA) were introduced to measure the domain alignment degree of the current cross-domain task feature representation and the diagnostic task decision boundary. A dynamic balancing factor was constructed to real-time adjust domain alignment loss and class discriminability loss, effectively aligning each class space between the source and target domains. Finally, validated by a collected gearbox fault dataset under variable operating conditions. The results show that the proposed method achieves diagnostic accuracy exceeding 95% across different conditions, demonstrating its feasibility and effectiveness.关键词：Gearbox;Variable operating condition;Fault diagnosis;Data fusion;Domain adaptation2|0|0更新时间：2025-04-03
- 摘要：As the key equipment for collecting signals, the coupling performance of oil and gas exploration geophone and earth vibration affects the quality of collected signals and determines the exploration accuracy. In order to improve the exploration ability of the geophone, the structure of the tail vertebra of the geophone was taken as the research object. Based on the single-degree-of-freedom coupling vibration theory, a vibration model for the coupling of the tail vertebra of the geophone and the earth surface under the sweep frequency signal was proposed. The acceleration,velocity and displacement response of the received signal of the tail vertebra of the geophone under the sweep frequency were extracted and analyzed. The coupling degree evaluation index of the mean value of vibration displacement and the standard deviation of vibration acceleration was established, and the coupling degree response of the tail vertebra of the geophone and the earth was mastered. Through the geophone receiving test, the maximum error between the acceleration signal received by the geophone tail vertebra and the acceleration signal received by the test was less than 15%, which verified the correctness of the model and method. Finally, based on the response surface method, the key parameters of the length and radius of the tail vertebra under different shapes were optimized. The results show that the coupling degree of the tail vertebra under the triangular pyramid shape is the best. The coupling mean value of the displacement of the optimized ground-geophone tail vertebra is reduced by 7.94%, and the standard deviation of the acceleration is reduced by 6.42%, which effectively improve the ability of the geophone tail vertebra to receive signals.关键词：Vibration coupling performance;Geophone tail vertebra;Coupling performance of swept-frequency vibration;Structural optimization2|0|0更新时间：2025-04-03
- 摘要：Metal structures are widely used in industry. Metal structures in service are prone to crack defects under tensile and compressive fatigue load.In order to realize quantitative detection of metal structures’ crack defects, a quantitative analysis method of metal structures’ weak magnetic detection based on back propagation (BP) neural network was studied. In view of the poor effect and low efficiency of BP neural network in parameter adjustment, the improved whale optimization algorithm (IWOA) based on Sine chaotic mapping was adopted to optimize the BP neural network parameter adjustment mode, giving consideration to global optimization while improving the local optimization ability, and then the optimal parameters searched by IWOA were assigned to BP neural network, improving the quality of initial network parameters.The length, width and depth of the artificial rectangular slot were quantified by inversion. The results show that the average prediction accuracy of IWOA-BP neural network is above 80%, and the prediction accuracy of depth, length and width is improved respectively by 106.72%, 9.68% and 6.86%.关键词：Weak magnetic detection;Metal structure;BP neural network;Whale algorithm;IWOA-BP neural network2|0|0更新时间：2025-04-03
·Vibration·Noise·Monitoring·Diagnosis·
- 摘要：To address the creep issue that arises during the long-term vertical storage of solid rocket motor (SRM), a method was proposed that involved embedding a specially shaped functional combustible core model (reinforcement structure)into the propellant grain matrix without altering the basic structure of the grain. Initially, the distribution patterns of creep in the propellant grain under the coupled effect of solidification cooling and vertical self-weight were analyzed by using three-dimensional numerical simulation methods. Subsequently, the reinforcement structure was designed by using the solid isotropic material with penalization (SIMP) method for topology optimization, determining the geometric configuration of the embedded reinforcement structure. Finally, the final optimized design results were determined through comparative analysis of the anti-creep effect of the topology-optimized reinforcement structure. The research results demonstrate that the deformation stress and strain of the solid rocket motor propellant grain with the reinforcement structure are significantly reduced compared to those without the reinforcement structure, effectively suppressing the creep of the grain.关键词：Solid rocket motor;Creep;Topology optimization;Finite element method0|0|0更新时间：2025-04-03
- 摘要：In the course of real operation, the drive axle housing is likely to undergo fatigue failure due to prolonged exposure to cyclic alternating loads.To determine whether the drive axle housing of a commercial vehicle’s wheel-side electric motor complying with fatigue life requirements at the design stage, a three-dimensional model and finite element model of the drive axle were established. Firstly, an initial inertia release analysis was performed，indicating that its static strength and stiffness met the requirements.Secondly, based on this foundation，utilizing nCode DesignLife software, using the nominal stress method in conjunction with the material’s S⁃N curve and fatigue loading curve, a new automotive industry standard was employed to predict the fatigue life of the housing under multiple conditions，such as vertical bending fatigue, braking fatigue and lateral fatigue.The results revealed that the fatigue life of the drive axle housing under braking fatigue and lateral fatigue conditions did not meet the requirements set out in the standard, necessitating structural optimization. Finally, reinforcement optimization was performed on the drive axle housing. The results show that, through optimization，the maximum stress of the drive axle housing is reduced by 95.8 MPa and the maximum deformation is decreased by 1.064 mm under the maximum impact conditions.Additionally, the minimum fatigue life under three different fatigue conditions is improved respectively by 1.076 million cycles, 289 000 cycles, and 497 000 cycles, exceeding the requirements stated in the standards.This validates the feasibility of optimizing the drive axle housing structure, effectively shortening and reducing the research and development cycles and associated costs.关键词：Drive axle housing;Inertial release;Fatigue life;Structural optimization2|0|0更新时间：2025-04-03
- 摘要：In order to solve the problem of multi-source heterogeneous data fusion and improve the accuracy of reliability evaluation, a multi-source heterogeneous data fusion method based on approximate failure point was proposed by using D-S theory and the least squares method.Firstly, the probability envelope curves were obtained through constructing probability assignment for a single source of data and performing weighted fusion.A distribution fitting model based on approximate failure points was also established.Secondly, the parameter estimation value was obtained by the least squares method, and the area metric was constructed to determine the true failure distribution function，and then the reliability assessment was completed.Finally, the feasibility and effectiveness of the proposed method were verified by examples, and the accuracy was higher than that of Bayes method.关键词：Multi-source heterogeneous data;D-S evidence theory;Approximate failure point;Least squares estimation;Area metric1|0|0更新时间：2025-04-03
- 摘要：Body centered cubic (BCC) structure has excellent mechanical properties, but the stress concentration phenomenon at the nodes limits its further development in mechanical properties. At present, the method of adding spherical nodes or variable cross-section pillars is commonly used to alleviate stress concentration at nodes and achieve strengthening design of lattice structures, but there is a lack of research on the influence of the volume ratio of nodes to pillars on the strengthening effect. A new type of variable cross-section pillar based on trigonometric function reduction is designed, and a variable cross-section body centered cubic lattice (VC-BCC) lattice is designed. Dynamic node design is achieved by directly connecting the pillars to explore the optimal node to pillar volume ratio. Theoretical formula estimation of the volume of VC-BCC lattice is carried out, and based on the Timoshenko beam model, the equivalent elastic modulus of VC-BCC lattice is theoretically analyzed. A simplified model is established using the method of equivalent cross-section. Finite element simulation analysis was conducted on VC-BCC lattice with different proportions of node pillars, and lattice specimens were manufactured using selective laser melting technology for quasi-static compression testing. The experimental results show that there is little difference between theoretical calculations and simulation analysis. The maximum stress of the VC-BCC lattice structure is significantly reduced, and the equivalent yield strength is significantly improved. In all analyses, the VC-BCC lattice structure with a variable cross-sectional parameter of 0.6 exhibited excellent performance and had the best overall mechanical properties.关键词：Node reinforcement;Lattice structure;Body centered cubic;Finite element simulation;Selective laser melting2|0|0更新时间：2025-04-03
- 摘要：In order to improve the traditional design concept and the lack of optimization of genetic algorithm, and promote the development and innovation of the shape optimization of truss structure, according to the basic principles of harmony search algorithm and genetic algorithm, a new hybrid genetic algorithm-harmony search genetic algorithm was proposed (the mixing of genetic algorithm and harmony search algorithm is to embed the harmony search operator after the operation of the genetic algorithm), and at the same time the cross-variation in the genetic algorithm was adaptively improved in three situations, and elitism and other improvement measures were introduced. In addition, the harmonious search algorithm is processed with mixed variables of discrete variables and continuous variables, and a truss structure shape optimization method based on the harmonic search hybrid genetic algorithm was established. In the optimization process, the two different types of design variables of node coordinates and cross-section area were considered uniformly, which solves the problem of difficulty in coupling of the two types of variables. Through the analysis of two typical examples, the results show that the harmonic search genetic algorithm (HS-GA) has efficient convergence speed and strong global ability. Compared with genetic algorithm (GA), heuristic particle swarm optimization (HPSO) and other optimization algorithms, the optimization effect is obvious, and it is a method suitable for the shape optimization of truss structure.关键词：Shape optimization;Harmonic search algorithm;Hybrid genetic algorithm;Adaptive genetic algorithm0|0|0更新时间：2025-04-03
·Optimization·Reliability·
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