This article presents a design method of Longitudinal-Bending Coupled Horn (L-BCH) of a giant magnetostrictive transducer utilized in spinning ultrasonic machining. The structural parameters are initially determined by the design theory of the horn and thick disc. Then, the effect of the structural parameters of the rotating wheel on the vibration characteristics of the L-BCH are explored by the model and harmonic response analysis through the finite element method. Through continuous modification of the geometrical parameters of the rotary wheel, the L-BCH meeting the requirements of a giant magnetostrictive transducer is designed. Finally, the frequency and amplitude measurements are performed on the prototype by the impedance analyzer and the laser vibrometer. The finite element analysis and experimental results show that: the large diameter, small diameter, thickness, and fillet radius of the rotating wheel have different impacts on the dynamic characteristics of the L-BCH. Among them, the thickness of the rotary wheel has the most significant influence on the natural frequency and amplitude. In addition, the rotating wheel has a pitch circle when the longitudinal-bending coupled vibration occurs, and the structure itself also has the characteristic of amplifying amplitude.

The multidimensional deployment of large-scale spatial solar arrays has been the basis for high-power advanced spacecraft and a symbol of the leaps forward in aerospace technology. Activated and passive drives have often been used in combination to implement the driving mechanism of large-scale solar arrays, which can reduce the impact of the deployment and locking process. For the first time, a novel active speed-limit mechanism was introduced into the two-dimensional secondary deployable drive system of a large-scale spatial solar array, achieving a balance between large deployable driving torque and small locking impact load. A highly integrated and lightweight drive system has been designed, integrating motor drive, gear drive, and adaptive torque limiting device to achieve adaptive control of the deployment torque of the solar array. A dynamic simulation system for the entire process of a large-scale spatial solar array based on the Kane method and ADAMS model has been established. A two-dimensional secondary deployable motion control law for a large-scale solar array using an active speed-limit mechanism has been established, and the dynamic characteristic parameters of the active speed-limit driving mechanism have been determined, such as driving torque, driving mode, and driving speed. The results can be used to guide the design of the deployable driving mechanism for large-scale spatial solar arrays.

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The continuity, self-similarity, and self-affinity of a microscopic contact surface can be described by the Weierstrass–Mandelbrot (W–M) function in fractal theory. To address the problems that the existing normal contact load fractal model does not take into account the effect of thermal stress and is not applicable to the temperature variation in the joint surface of the giant magnetostrictive ultrasonic vibration systems, a fractal model of thermal–elastic–plastic contact normal load fractal is established based on fractal theory. The model is an extension of the traditional model in terms of basic theory and application scope, and it takes into account the effects of temperature difference, linear expansion coefficient, fractal dimension, and other parameters. Finally, the effect of the temperature difference at the joint surface on the normal load of the thermoelastic contact is revealed through numerical simulations. The results show that the nonlinearity of the contact stiffness of the thermoelastic joint surface is mainly related to the surface roughness and the fractal dimension, while the effect of the temperature change on the joint surface properties within a certain range is linear.

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