The nonlinear dynamic responses of a wire rope under periodic excitation in a friction hoisting system are investigated. Longitudinal excitation experiments of different periodic excitation frequencies are performed. The nonlinear dynamic characteristics of the rope, including transverse, longitudinal, and coupled vibrations, are discussed with time-frequency analysis. The results show that the transverse vibration is a forced vibration following the excitation, while the longitudinal vibration shows a complex, random vibration state. The vibration amplitude and intensity deviate significantly from their linear trend (superharmonic resonance) at some excitation frequencies, and this deviation indicates the typical nonlinear multiorder natural frequency characteristics. The lifting motion can lead to additional corrugated high-order harmonics and cause a fundamental wave distortion of low-frequency excitation. Experimental evidence for the coupling characteristics of the transverse-longitudinal rope vibration in the lifting process is found.

In this paper, the finite element (FE) model of the three-dimensional (3-D) transient thermo-stress field of a brake shoe was established and then the software ANSYS 13.0 was used to get the numerical solutions; an experiment was carried out on the X-DM friction tester to verify the FE model. It was found that both the whole temperature and the equivalent stresses of the brake shoe increased and then decreased during mine hoist emergency braking; region of 1 to 3 mm below the friction surface was suffered to larger temperature gradients and stresses.

The shortcomings of conventional human instrument inspection, such as its low efficiency, high risk, and data latency, have been made clear by the rapidly growing trend of industrial automation and intelligentization. An essential instrument for unmanned operation and maintenance is the instrument and meter inspection robot, which combines multimodal sensors, autonomous navigation, and intelligent identification technologies. The technical foundation and current state of application for instrument and meter inspection robots are systematically reviewed in this study. We critically examine the advancements in instrument recognition research and present the sensors, autonomous navigation algorithms, and identification technologies utilized in instrument and meter inspection robots. We tested a prototype of a standard wheeled inspection robot in the instrument inspection of a cement plant and reported the test findings to further examine the viability of inspection robots. Furthermore, we evaluate the challenges in the development of instrument and meter inspection robots and propose potential avenues for future research.

Fast computation of the elastic deformation integrals of dry contact is accomplished using multigrid techniques. The method is called multi-level multi-integration, which enables the efficient numerical solution of contact pressure for large dry-contact problems. The computing effort can be reduced to O (NlogN) operations, compared to that of classical solution methods, O (N²). The fast integration technique can be straightforwardly applied to computing sub-surface stresses. As an example, the pressure and stress distribution of the contact of wire rope and friction lining, a large calculation due to the wire rope’s complicated construction, were fast solved. Subsequently, the friction lining’s transient temperature, when the wire rope was sliding, was solved using multigrid techniques.

In lubricated contacts, the component macrogeometry (radius of curvature) determines the pressure generation, and the surface microgeometry (i.e., roughness) alters it somewhat. However, for parallel surfaces, the microgeometry completely determines the hydrodynamic lubrication. This paper extends earlier work to numerically solve the isothermal hydrodynamic pressure generation and load carrying capacity (LCC) of surfaces with more complicated roughness features. A fast Fourier transform (FFT)-based method is described to quickly obtain the pressure distribution. The method is applicable to both real surface topographies and artificially generated rough surfaces. Results show that it enables one to predict the hydrodynamic pressure, when cavitation is negligible. The relative error of the LCC over the central domain is smaller than 8% and a 500× time saving, compared with the numerical method, is obtained.

Introduction: Exhaust mufflers are widely utilized across a range of equipment and facilities that produce aerodynamic noise, providing notable benefits such as noise mitigation, environmental enhancement, and improved equipment stability. Nevertheless, they are also linked to certain challenges, including heightened back pressure, increased costs, and complexities in cleaning and maintenance. Methods: This article presents patents aimed at enhancing the noise reduction performance of exhaust mufflers, as well as academic literature on their performance optimization, providing valuable references for research on muffler design. Results: Integration of noise-reduction structures with sound-absorbing materials enables substantial enhancement of exhaust muffler performance. This approach not only strengthens noise attenuation efficacy and elevates exhaust efficiency but also improves environmental adaptability, thus providing a comprehensive solution for effective noise control. Discussion: A multi-stage impedance composite muffler design yields significant performance enhancements, which are attributed to sequential noise attenuation via multi-staging and expanded noise reduction bandwidth through the impedance composite configuration. Conclusion: This paper provides essential references for optimizing and improving exhaust mufflers, offering specific guidance for enhancing their filtration capabilities and noise reduction performance. It notably advances the efficiency of noise control in industrial applications.