As a typical self-excited vibration phenomenon in metal cutting processes, chatter leads to deteriorated machining surface quality, manifested by texture fluctuations, increased dimensional errors, and compromised surface integrity. Effective detection and suppression of chatter is crucial for ensuring machining efficiency and enhancing component performance. Current research has established a multi-dimensional technical framework encompassing physics-model-based offline prediction methods, multi-sensor signal-dependent experimental detection schemes, and intelligent algorithm-integrated online monitoring frameworks. However, existing review literature lacks in-depth dissection of this domain. Addressing this gap, this study conducts a systematic technical review and analysis focusing on chatter detection and suppression technologies.For chatter detection, an analytical-experimental dual methodological framework is established, emphasizing the dissection of applicability scenarios and performance boundaries of various techniques. In terms of chatter suppression, a triple control strategy classification system integrating active-passive-parameter adjustment is constructed, comparing implementation costs and vibration attenuation effects of different solutions. Based on multi-dimensional technical comparisons and cross-disciplinary method integration, existing challenges and potential solutions in this field are explored, providing comprehensive theoretical support and technical references for subsequent research.

To enhance the assembly connection performance of adhesive structures in heavy machinery and aerospace equipment, a numerical analysis model based on the cohesive force element was developed to investigate the failure behavior of adhesive joints. The evolution of shear stress distribution in the adhesive layer during the tensile-shear failure process under different loading stages was analyzed. The variations in ultimate failure load and structural stiffness with different adhesive joint parameters were systematically studied, and tensile-shear failure tests were conducted. The results indicate that the shear stress distribution in the adhesive layer transitions from an initial U-shaped profile to an M-shaped and finally evolves into an approximately inverted U-shaped pattern as the load increases. Increasing the length or width of the adhesive layer significantly improves both the ultimate failure load and overall structural stiffness. However, increasing the adhesive layer thickness or substrate thickness exhibits a minor effect on the ultimate failure load. Notably, the structural stiffness decreases with increasing adhesive thickness but increases with higher substrate thickness.

In order to study the evolution laws of microstructure and properties during the hot ring rolling, carburizing heat treatment, and deep cryogenic treatment of high-speed railway bearings, the quantitative relationships among the forming manufacturing conditions, microstructure states, and mechanical properties of high-speed railway bearings were established.The optimal process conditions for high-performance forming manufacturing of high-speed railway bearings were determined.The electron back-scatter diffraction (EBSD), scanning electron microscope (SEM), X-ray diffraction (XRD) microstructural testing technologies and tensile, friction and wear, rolling contact fatigue performance testing technologies were used to reveal the evolution laws of the microstructure and mechanical properties of high-speed railway bearing rings during the forming and manufacturing process, and a forming and manufacturing process method for high-performance high-speed railway bearing rings was proposed. The research shows that ring rolling can refine grains, promote the refinement of carbides and increase the dislocation density after carburizing once quenching and tempering, reduce the grain size and carbides, and improve the volume fraction of carbides after secondary quenching and tempering. The deep cryogenic treatment process promotes the decomposition of retained austenite and the precipitation of carbides, reduces the content of retained austenite, enhances the stability of retained austenite, decreases the average size of carbides, and increases the volume fraction of carbides. The wear resistance of high-speed railway bearings is improved by 82.7%, and the contact fatigue performance is improved by 322.1%by applying the optimal hot ring rolling and carburizing heat treatment processes. The research can provide a scientific basis and technical method for the high-performance forming manufacturing of high-speed railway bearings.

In response to the problems of reduced surface quality and severe twist drill wear in HR-2 hydrogen resistant steel deep small holes drilling, integrated thermal coupling finite element simulation with experimental investigations of deep small holes drilling to analyze the variations in tool wear, drilling temperature, and the quality of the machined surface during the process of machining deep small holes. The improvement effect of introducing ultrasonic vibration on poor surface quality and severe tool drilling wear was analyzed by comparing ultrasonic vibration assisted drilling (UVAD) and conventional drilling (CD). The results show that as the drilling depth increases, the heat accumulation of the tool's transverse and cutting edges significantly increases, gradually leading to problems such as coating peeling, edge passivation and chipping.Concurrently, the accumulation of cutting heat on the surface of the machined hole causes temperature rise, resulting in material coating, debris adhesion, oblique scratching and other problems on the machined surface, resulting in a deterioration of surface quality and an elevation in surface roughness. Compared to CD, the UVAD effectively reduces drilling temperature,helps to reduce tool wear and maintain cutting edge integrity, while suppressing the increase in surface roughness during machining, ultimately improving surface quality.

Different parts of high-speed train bogies are usually designed with aluminum alloy materials of varying strengths, and welding is adopted to connect these different parts. When high-speed trains operate under complex road conditions, the bogies will be subjected to tensile overload, which will produce a coupled superposition effect with the strength difference of welded joints. Therefore, tensile overload tests were carried out on the welded structural components of bogies to study the fatigue crack growth behavior and intrinsic mechanism of aluminum alloy welded joints with different strengths under the action of tensile overload. The compliance method was used to measure the crack growth rate under tensile overload;the digital image correlation (DIC) technology was applied to analyze the change in the size of the plastic zone at the crack tip before and after the application of tensile overload; the scanning electron microscope (SEM) was employed to observe the fracture morphology characteristics of different aluminum alloys in the region affected by tensile overload. The crack growth behavior and intrinsic mechanism under tensile overload were explained based on the change in the size of the plastic zone at the crack tip and the corresponding fracture morphology characteristics. The results show that a single tensile overload can reduce the fatigue crack growth rate and extend the fatigue life. Further analysis indicates that during the tensile overload process, the plastic zone at the crack tip expands and the crack tip is blunted, which together lead to the reduction of the fatigue crack growth rate. The lower the material strength, the more severe the deformation at the crack tip and the more obvious the hysteresis effect under the same tensile overload. The test results of welded joints under tensile overload are consistent with those of the base metal, suggesting that the strength of the hysteresis effect depends only on the inherent strength of the material itself.

High-temperature mechanical strength is a key performance determinant for the long term, stable operation of advanced energy systems and components in high-temperature service and has been a disciplinary branch in the mechanical strength theory. Its research and development have accompanied major industrial technological advances. The research paradigm has shifted from early empirical formulas and single damage model to a structural integrity assessment framework characterized by mechanistic interpretability, prediction orientation, and evidential reproducibility. Building on the historical trajectory of the field together with bibliometric analysis and keyword clustering, the phase specific migration of research hotspots and the evolving knowledge structure were delineated. Recent progress was synthesized along three complementary themes, namely multiscale modeling, multiple damage coupling, and multidisciplinary integration. The synthesis covered material deformation and damage mechanism, damage evaluation and life assessment, and in-service monitoring and reliability assessment, thereby establishing a traceable mapping from microstructural mechanisms to engineering applications. Looking ahead, advances are expected to deepen in multiphysics coupling, intelligent decision-making algorithms, and standards system development. Critical challenges include bridging high-fidelity models and real-time prediction, establishing robust mappings from microstructure to service life, and translating theoretical modeling into engineering codes.

At present, the deterministic design and evaluation of high-temperature structural strength have been fully developed and formed a relatively complete system framework, laying the theoretical foundation for the design and manufacturing of numerous mechanical equipment under harsh service conditions. Considering the randomness of high-temperature structural failure and the small-sample characteristics of failure data, safety factors are usually adopted for conservative design in engineering. However, this often leads to structural redundancy and cost waste, so there is an urgent need to conduct research on design methods from determinism to uncertainty. Nevertheless, no universal and mature theoretical methods for high-temperature structural reliability or national/industrial standards have been established so far,making it difficult to effectively predict and guarantee the reliability of high-end equipment such as China's aero-engines during operation. Based on this, firstly, uncertainty analysis was elaborated. The damage-threshold interference criterion was introduced in detail, and its differences from and connections with the stress-strength interference criterion was explained.Finally, taking a certain steam turbine rotor as an example, it illustrates the engineering application of the damage-threshold interference criterion in the reliability analysis of high-temperature structures.

To address the insufficient stability of high-altitude line inspection robots under wind loads, this study proposes optimization strategies involving a novel elastic pressing mechanism and an improved wheel groove, which can effectively enhance their walking stability. A power transmission and distribution line inspection robot with dual-mode switching (flight and walking) capabilities was developed. Firstly, a dynamic model of the robot under wind loads was established, and the relationship between the swing decay time and clamping force, contact area, and friction coefficient was derived. Secondly,dynamic simulations were conducted to verify the performance advantages of the two optimization strategies in suppressing swings. Finally, outdoor wind swing tests were performed to validate the effect of structural improvements. The results show that the elastic pressing mechanism can effectively increase the contact area between the pressing wheel and the line, and the improved wheel groove can enhance the friction coefficient of the walking wheel; both significantly shorten the robot's swing decay time and improve its inspection stability in wind load disturbance environments. The effective technical support and engineering practice basis for the stable operation of high-altitude line inspection robots in complex environments were provided.

To address the problems of unclear internal load evolution law of the electromechanical composite transmission system for high-speed tracked vehicles and the lack of fatigue life prediction method for planetary gear bearings,a dynamic model of planetary gear bearings in the electromechanical composite transmission system was established to obtain the distribution law of contact loads on planetary gear bearings. A fatigue life prediction method based on the dynamic load characteristics of planetary gear bearings was proposed, which provides certain guiding significance for the optimization and design of the planetary mechanism in the electromechanical composite transmission system. Considering the effects of multi-row coupling effect of the electromechanical composite transmission system, gear time-varying meshing stiffness excitation,and nonlinear support stiffness excitation of planetary gear bearings, a dynamic model of the electromechanical composite transmission system was established using Simpack to obtain the load-bearing conditions of planetary gear bearings.Furthermore, a dynamic model of planetary gear bearings was established using the lumped mass method to analyze the evolution law of contact loads on planetary gear bearings. Then, a fatigue life analysis and prediction model for planetary gear bearings was established using the L-P formula to analyze the variation law of fatigue life of cylindrical roller bearings for planetary gears under different working conditions. The results show that at high rotational speeds, the centrifugal force of the planetary gear bearings during revolution has a significant impact on the contact loads and fatigue life of the planetary gear bearings. At lower rotational speeds, the service life of the planetary gear bearings in the reduction gear increases with the rotational speed. At higher rotational speeds, the service life of the planetary gear bearings in the reduction gear decreases with the increase in rotational speed. At high rotational speeds, measures such as profile modification of the rolling elements of planetary gear bearings can be taken to extend the service life according to the life requirements of the electromechanical composite transmission system.

To address the issue of characterizing static and dynamic mechanical behaviors of the surface-modified layer (SML) in 18CrNiMo7-6 alloy steel, a layered inversion method for the Johnson-Cook (J-C) constitutive model of SML was proposed. The SML was subjected to layered processing, and dynamic compression tests were conducted on cylindrical specimens with different SML thicknesses. Through progressive parameter inversion, the strain rate sensitivity coefficient C at each depth of the SML was determined. Combined with quasi-static thin plate tensile tests at different temperatures for each depth of the SML, the corresponding yield strength A, strain hardening coefficient B, strain hardening index n, and thermal softening exponent m were determined. Test results show that the SML of 18CrNiMo7-6 alloy steel exhibits significant strain hardening, strain rate strengthening, and temperature softening effects. Additionally, a correlation model between J-C constitutive parameters and dimensionless depth h/h_b (distance to SML surface/SML effective depth) was established,providing support for subsequent composite strengthening simulations.