Vol. 60 No. 6 (2026): In Progress

  • Open Access

    Article

    Article ID: 4379

    Structural modal study of vertical system vibration based on large axial Cross-Wedge rolling mill

    by Chuanchuan Ma, Xinglong Zhao, Wenchang Zhong, Junjie Wang, Junsheng Xu, Yang Zhang, Zhibing Chu

    Sound & Vibration, Vol.60, No.6, 2026;

    With the surge in demand for large shaft components in the railway transportation industry, traditional rolling mills are insufficient to meet actual production needs, leading to the development of wedge cross-rolling mill equipment suitable for producing large shaft components. This paper focuses on the study of the vibration characteristics of the vertical system of large axial Cross-Wedge rolling mill. By constructing a four-degree-of-freedom (4-DoF) vertical vibration dynamic model of the mill frame structure, the vibration characteristics of the vertical system were investigated, and the natural frequencies and main vibration modes of each order were obtained. To facilitate subsequent research and optimization of the overall mill structure, the 4DoF vertical system model was simplified into a symmetric single-degree-of-freedom (SDoF) model, and the sensitivity of the second-order mode to stiffness was explored. At the same time, finite element analysis (FEM) was used to conduct modal analysis on the mill vertical system, and vertical system velocity signals were obtained through on-site data collection. The results indicate that the simplified vertical system structural model matches the vibration characteristics of the mill's vertical system, and the natural frequencies of the vertical system calculated are basically consistent with the results from modal analysis and on-site data collection. This study provides a theoretical basis for the prediction, diagnosis, and structural parameter optimization of vertical vibration in large axial Cross-Wedge rolling mill.

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  • Open Access

    Article

    Article ID: 4699

    Interval type-2 fuzzy α-plane minimax co-design of multi-tuned mass dampers for broadband vibration control under bounded uncertainty

    by Suleiman  Ibrahim Mohammad, Yogeesh  Nijalingappa, Seif Al  Bustanji, Poornachandran  William, Asokan  Vasudevan

    Sound & Vibration, Vol.60, No.6, 2026;

    Passive tuned mass dampers are effective near their design frequencies but can lose performance or exceed travel limits when structural properties are imprecise. This paper develops an interval type-2 fuzzy α-plane minimax method for the simultaneous allocation, tuning, and damping design of a three-absorber bank on a six-degree-of-freedom coupled machine–foundation system. Primary mass, stiffness, and damping are represented by lower and upper triangular membership functions, so uncertainty in both parameter values and membership widths is retained. At every α-plane, outer and inner vertex responses are propagated through the complex frequency-response matrix. A membership-weighted objective combines worst peak acceleration, broadband root-mean-square acceleration, footprint width, and a 16 mm relative-stroke constraint. Differential evolution determines nine absorber variables for a fixed 6% auxiliary-mass budget. The frequency-domain solver reproduces classical equal-peak tuning ratios to machine precision and absorber damping ratios within 0.20%. In 2,048 independent outer-support Sobol scenarios, the proposed design decreases the mean peak acceleration from 6.058 g to 1.262 g and the worst peak acceleration from 9.005 g to 1.682 g. The deterministic optimum attains a smaller mean peak of 1.112 g but violates the stroke constraint in 55.42% of the scenarios; the type-1 robust design violates it in 2.05%, whereas the proposed design has no violations and a maximum stroke of 15.992 mm. The results show that explicitly preserving membership-function uncertainty changes the mass allocation and first-mode detuning sufficiently to obtain a feasible broadband design without active control.

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