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This study aims to investigate the bending performance and evaluation of aluminum‐carbon fiber reinforced plastic (Al‐CFRP) riveted laminates under varying parameters via self‐pierce riveting and three‐point bending tests. Through the self‐pierce riveting process test, a riveted joint meeting standard requirement was obtained. Based on this joint combination form, Al‐CFRP self‐pierce riveted laminates were prepared. The bending performance test showed the riveted laminate with a span of 80 mm had the greatest bending resistance at a thickness of 2 mm, and the overall strain of the Al‐CFRP self‐pierce riveted laminates was observed by digital image correlation (DIC) technology. Subsequently, validated numerical simulation modeling was conducted by correlating with the test results. On this numerical simulation model basis, further parametric studies and bending performance evaluations (including number of rivets, CFRP lay‐up angle, and laminates width) of the Al‐CFRP self‐pierce riveted laminates were systematically carried out. It was found that the peak load F and bending strength R improved by 1.32% and 26.66%, respectively, while the mass M reduced by 8.99%, for the design variables of var1 of 20 mm, var2 of 6, and var3 of [0/90°]2s. Highlight: An Al‐CFRP riveted laminate structure is proposed to improve the bending properties of riveted laminates by changing the rivet parameters and laminate parameters.The bending properties of riveted laminates with different spans were investigated under three‐point bending loading conditions.The DIC technique observed the changes in the strain field of riveted laminates during bending.The effects of different structural parameters on the bending performance of Al‐CFRP riveted laminates were investigated by numerical simulation.An evaluation method combining the gray correlation degree and the combination assignment method is proposed to obtain the optimum riveted laminate structure under bending load conditions. [ABSTRACT FROM AUTHOR]

With the widespread adoption of mobile robots, effective path planning has become increasingly critical. Although traditional search methods have been extensively utilized, meta‐heuristic algorithms have gained popularity owing to their efficiency and problem‐specific heuristics. However, challenges remain in terms of premature convergence and lack of solution diversity. To address these issues, this paper proposes a novel artificial potential field enhanced improved multiobjective snake optimization algorithm (APF‐IMOSO). This paper presents four key enhancements to the snake optimizer to significantly improve its performance. Additionally, it introduces four fitness functions focused on optimizing path length, safety (evaluated via artificial potential field method), energy consumption, and time efficiency. The results of simulation and experiment in four scenarios including static and dynamic highlight APF‐IMOSO's advantages, delivering improvements of 8.02%, 7.61%, 50.71%, and 12.74% in path length, safety, energy efficiency, and time‐savings, respectively, over the original snake optimization algorithm. Compared with other advanced meta‐heuristics, APF‐IMOSO also excels in these indexes. Real robot experiments show an average path length error of 1.19% across four scenarios. The results reveal that APF‐IMOSO can generate multiple viable collision‐free paths in complex environments under various constraints, showcasing its potential for use in dynamic path planning within the realm of robot navigation. [ABSTRACT FROM AUTHOR]

Combined simulation and test to investigate the collapse failure mode and energy absorption characteristics of wingding carbon fiber reinforced composite（CFRP[± 45°/90°]）/Al hybrid thin-walled circular tube under quasi-static axial compression load. Failure mode,Load-displacement curves and energy absorption characteristics were obtained under quasi-static axial crushing tests. A finite element model of hybrid tube was established according to samples. The simulation results with good agreement with the test were obtained by ABAQUS/Explicit,and the crushing failure behavior of the hybrid tube under quasistatic load was reproduced. Based on the simulation results,it was found that the initial crushing load,average crushing load,specific energy absorption and load efficiency of the mixing tube were increased by 97. 6%,93. 3%,57. 8% and 5. 9%,respectively. compared with the aluminum tube. The staged peaks and valleys of the crushing load were selected to analyze the shape of hybrid tube and the failure state of the fiber damage. The results show that when the hybrid tube is complete the fiber plays the main bearing role. In the crushing failure stage,the fiber damage failure mode changes with fiber winding angle,the crushing morphology of aluminum tube and the bonding interface state of CFRP/Al. Subsequently,the energy absorption characteristics of CFRP/Al hybrid circular tubes with three different structure forms were compared. It was found that hybrid circular tube with CFRP[90°/± 45°] wrapped the outside of the aluminum has the best energy absorption.

The quasi-static radial compression performance of carbon fiber reinforced plastic（CFRP） wound thin-walled aluminum tubes was studied by means of experimental research,theoretical and simulated analysis.Based on the joint action of aluminum and CFRP tubes,the theoretical model of initial failure load and total energy absorption of Al-CFRP hybrid tube under radial compression is established firstly.Then,the quasi-static radial compression experiment of Al-CFRP hybrid tube is carried out and the results show that the experimental results are in good accordance with the theoretical results which verifies the accuracy of the theoretical model that is carried on the supplementary improvement by finite element simulation.Based on the established theoretical model,the effects of winding angle of carbon fiber and the layer thickness ratio of aluminum tube and CFRP tube on initial failure load and total energy absorption of the hybrid tube were studied.The results show that the initial failure load and total energy absorption of the hybrid tube with a stable failure mode and bearing capacity are higher than those of the aluminum tube under quasi-static radial compression;The initial failure load and total energy absorption of the hybrid tube decrease first and then increase with the increase of the winding angle of carbon fiber and the thickness ratio of Al-CFRP layer.

The working condition of the rail transit components such as bogies is complicated, so the high comprehensive performance of composite parts is desperately required. However, existing pure three‐dimensional braided or laminated composites have been unable to satisfy the cooperative demand of in‐plane and interlaminar properties. In this paper, a novel design of three‐dimensional braided/unidirectional (3D/UD) hybrid composite is proposed to balance the in‐plane (tensile, compression, bending), interlaminar (interlaminar shear, low‐speed impact) properties of the composite. The effects of different 3D/UD mixing ratio and layup sequence on the mechanical properties and damage mechanism of hybrid composites were studied by the parametric analysis of the experimental test results, and the comprehensive mechanical properties of the hybrid structure were optimized by COPRAS evaluation method. The results show that the larger the proportion of unidirectional layer, the better the mechanical property in‐plane, but the worse interlayer property. In addition, the change of layup sequence induces a complex nonlinear relationship between 3D/UD mixing ratio and mechanical properties. Combined with microscopic failure characterization results, it is found that the sandwich structure and the addition of uniformly distributed interfacial layer can improve the mechanical properties of the hybrid composite. The optimization results show that the sandwich structure hybrid composite UD6/3D/UD6 with the best balance between in‐plane and interlaminar properties was selected by COPRAS. Compared with pure 3D composites, the comprehensive mechanical properties of UD6/3D/UD6 are increased by 53.9%, which provides a reference for the structural design of hybrid composites in the future. Highlights: A novel design of 3D/UD hybrid composite is proposed to balance the in‐plane and interlaminar properties.The influence regularity of 3D/UD mixing ratio and layup sequence on properties of hybrid composites were obtained.The mixing failure mechanism of interlayer and in‐plane was revealed.The optimal structure UD6/3D/UD6 under complex working conditions was obtained by COPRAS. [ABSTRACT FROM AUTHOR]

With the continuous development of intelligent construction machinery, the traditional hydraulic breaker with complex structure and single function has been gradually replaced by the increasingly mature intelligent breaker. The recognition and localization of multi-target stones is an important guarantee for intelligent crushing to improve the accuracy of action output and complete the crushing task. A target stone recognition and localization method based on segmentation-mask convolutional neural networks (Mask R-CNN) instance segmentation and light detection and ranging (LiDAR) information fusion was proposed. The Mask R-CNN instance segmentation algorithm was used to quickly identify the region of interest (RoI) of the target stone in complex operation scenarios. On the premise of ensuring the accuracy of stone detection, the position information of the crushing point was obtained by fusing lidar and the Kalman filter algorithm to guide the crushing hammer to realize the positioning operation. The results of the field tests show that the average recognition accuracy of the stone target detection model for stones is 95.35%, the recall rate is 95.06%, and the accuracy of stone breaking point recognition is 94.20%, can meet the real-time requirements. [ABSTRACT FROM AUTHOR]

Insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) is an important energy transfer and conversion component of electric vehicles. But working under varying conditions for a long time will result in high heat loads, which seriously affect IGBT service life. By establishing IGBT junction temperature estimation model for real-time temperature observation, the relationship between IGBT junction temperature, switch frequency and bus voltage was analyzed. In order to reduce the heat load of IGBT under cyclic conditions, the IGBT junction temperature regional control strategy was proposed. Aiming at controlling the maximum junction temperature and the junction temperature fluctuation, the control region was divided, and the switching frequency and bus voltage were controlled by fuzzy control and PI control respectively. The results show that the maximum junction temperature decreases by 5.1 °C and the junction temperature fluctuation of IGBT decreases by 2.6 °C on average under new European driving cycle (NEDC) condition, which verified the effectiveness of the control strategy and improved the reliability and operation life of IGBT. [ABSTRACT FROM AUTHOR]

The precise detection of polyester filament yarn (PFY) tension in the spinning process is critical to ensure product quality. The laser Doppler vibrometer (LDV) method is proposed to achieve non-contact detection of PFY tension in this paper. By employing the Hamilton principle, the transverse dynamics differential equations of PFY are derived, which are discretized and solved by the Galerkin method and Runge–Kutta method, respectively. In the equations, the PFY between two adjacent rollers is simplified as an axially moving string to verify the generality of calculating natural frequencies. The calculated natural frequencies from the axially moving string model are compared with solved results from the transverse dynamics differential equations. It is shown that the approximation of natural frequencies can be obtained from the axially moving string model. This study attempts to establish an approximate generic model among the PFY tension, the spinning speed and the first natural frequency based on axially moving string model, from which the PFY tension can be calculated efficiently by employing the measured natural frequencies. The LDV method is used to measure the natural frequencies. A major advantage of the proposed method is to realize non-contact detection of PFY tension. The method is more useful under high-speed spinning conditions where contact tension detectors are not available. An experimental analysis is carried out to verify the effectiveness and accuracy of the proposed method. Therefore, it is believed that the non-contact detection of PFY tension in the spinning process by the LDV method is feasible. [ABSTRACT FROM AUTHOR]

Composite/metal hybrid structure has both the advantages of light weight and high strength of composite materials and the advantages of low cost and easy connection of metals, which has great prospects for automotive applications. It is significant to investigate the energy absorption characteristics and theoretical analysis of Composite/Metal hybrid structures under transverse loading. Our study uses the example of CFRP/steel hybrid tube to explore bending deformation behaviour and energy absorption characteristics of the structure by experiment and theoretical analysis based on three-point test. Here, the effects of different winding sequences and thickness (4-ply, 8-ply, and 12ply) of CFRP were performed at three-point bending test, and all specimens were guided by metal tubes to stabilise bending collapse, and the influence of winding sequences on energy absorption and bending resistance is greater than that of numbers of winding layers. The result showed that the specific energy absorption of CFRP/steel hybrid tube with [±45°/90°/90°]2 winding modes was the best, which was 21.4% higher than that of Large-Diameter (LD) steel tube. The bending theoretical model of composite/metal hybrid tube based on Poonaya's model was performed to predict bending behaviour of hybrid tube. The theoretical result is in good agreement with the experiments, and the bending collapse behaviour is related to the hinge lines formed by CFRP with different angles. The bending theoretical model was modified by considering the hardening behaviour of the material, and can be applied to study on bending behaviour of CFRP/metal hybrid tube by the validation of the CFRP/Al hybrid tube. [ABSTRACT FROM AUTHOR]

To improve the crashworthiness and reduce vehicle weight, a crash box made of carbon fiber reinforced plastics (CFRP)/aluminum (Al) hybrid materials was introduced in the paper. Quasistatic axial compression tests and numerical simulations were conducted for pure Al tubes and CFRP/Al hybrid tubes. The simulation models were validated and were further employed to investigate the effects of geometry, aluminum tube thickness, fiber wrapping angle and CFRP layers on the crashworthiness of the hybrid crash box under axial loading and 30° oblique collision. The multiobjectives were taken to obtain the optimal geometrical dimensions, aluminum tube thickness, wrapping angle, and the number of layers. The crashworthiness of the optimal CFRP/Al hybrid crash box was compared with that of original aluminum crash box. It was found that the mass of the crash box was reduced by 35.21%, while the specific energy absorption (SEA) and mean crushing force (Fmean) were increased by more than 18% and 46%, respectively. The paper was aimed to provide some references for the design and optimization of composite crash box. [ABSTRACT FROM AUTHOR]