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As high-temperature-resistant inorganic fibers, Al 2 O 3 fibers possess high-temperature resistance, high-temperature oxidation resistance, and chemical stability, and thus are suitable for applications such as high temperature catalysis and filtration. However, their shortcomings, such as high brittleness and high fracturability, limit their applications. In this study, a flexible Al 2 O 3 /aramid composite felt was prepared by introducing aramid fibers into Al 2 O 3 fiber filaments, and the flexibility of the prepared composite felt was improved by using needle punching. The influence of the Al 2 O 3 /aramid doping ratio on the thermal insulation performance of the composite felt was explored. The findings showed that as the Al 2 O 3 /aramid doping ratio increased, the thermal insulation performance of the composite felt improved, whereas its thermal conductivity decreased. At room temperature of 25 °C and with an Al 2 O 3 /aramid doping ratio of 12:1, the thermal conductivity of the composite felt reached its minimum value of 0.0306 W m−1 K−1, while its compression and fracture moduli became 0.4 MPa and 21.5 GPa, respectively. The thermal-insulation mechanism of the composite felt was also explored in the study. [ABSTRACT FROM AUTHOR]

As high-temperature-resistant inorganic fibers, Al 2 O 3 fibers possess high-temperature resistance, high-temperature oxidation resistance, and chemical stability, and thus are suitable for applications such as high temperature catalysis and filtration. However, their shortcomings, such as high brittleness and high fracturability, limit their applications. In this study, a flexible Al 2 O 3 /aramid composite felt was prepared by introducing aramid fibers into Al 2 O 3 fiber filaments, and the flexibility of the prepared composite felt was improved by using needle punching. The influence of the Al 2 O 3 /aramid doping ratio on the thermal insulation performance of the composite felt was explored. The findings showed that as the Al 2 O 3 /aramid doping ratio increased, the thermal insulation performance of the composite felt improved, whereas its thermal conductivity decreased. At room temperature of 25 °C and with an Al 2 O 3 /aramid doping ratio of 12:1, the thermal conductivity of the composite felt reached its minimum value of 0.0306 W m−1 K−1, while its compression and fracture moduli became 0.4 MPa and 21.5 GPa, respectively. The thermal-insulation mechanism of the composite felt was also explored in the study. [ABSTRACT FROM AUTHOR]

• A multiparameter variable TPD is designed for vibration control of a manipulator. • The TPD achieves vibration suppression of a large mass with a small control mass. • The vibration reduction effects of the TPD outperform those of DVAs and PDs. • A comparison analysis of TPD and DVA explores the working acceleration threshold. • The TPD can adaptively adjust to achieve optimal vibration absorption. A novel lightweight variable-stiffness tuned particle damper (TPD) is designed to efficiently control low-frequency vibrations across a wide frequency range in manipulators, combining particle damping technology with dynamic vibration absorber principles. This study aims to integrate both theoretical and experimental approaches to comprehensively investigate the TPD's variable stiffness, damping characteristics, and vibration attenuation efficacy. Methodologically, the research entails designing and analyzing the TPD's variable stiffness mechanism, establishing a coupled dynamic model between the TPD and the manipulator, fabricating a prototype TPD, and subsequently evaluating its frequency variability range and vibration control effectiveness. Additionally, the study explores the semi-active control capabilities of the TPD. Results demonstrate that the designed TPD, utilizing a single 100 g particle, achieves a substantial 60 % reduction in manipulator amplitudes within the 5–10 Hz frequency range. Moreover, the study identifies the TPD's operational acceleration threshold to be 0.6 g, thereby broadening its applicability across various scenarios. Furthermore, the integration of semi-active control algorithms augments the absorption frequency band. These findings highlight that the TPD offers multi-parameter adjustability in stiffness, damping, and mass, with a lighter mass compared to traditional dynamic vibration absorbers. It can effectively mitigate vibrations without altering the original system's dynamic characteristics, presenting a promising solution for engineering applications necessitating versatile and efficient vibration control mechanisms. [ABSTRACT FROM AUTHOR]