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In this paper, a tunable-focus liquid lens driven by a novel piezoelectric motor is proposed for the adaptive application. Compressing the liquid chamber, the curvature of the lens can be changed by increasing the liquid pressure. This mechanism requires the motor to provide a vertical force to deform the lens surface, whose curvature can be decreased and thereby increasing its focus. As a key part of the tunable-focus liquid lens, a novel piezoelectric motor with the compact structure is emphatically developed in this paper. The operation process of the motor is discussed in detail, whose geometrical parameters are calculated by the finite element simulations. And the motor prototype is then fabricated and tested by the experimental platform. The testing results indicate that the motor can operate steadily and continuously, whose maximum linear velocity can reach 0.065 mm/s under the frequency of 11.80 kHz and voltage of 400 [Formula: see text]. The measurement shows that the proposed lens driven by the piezoelectric motor can zoom ranged from 9.6 mm to 17.9 mm, which is suitable for adaptive eyeglass application. Compared with other liquid lens, the prototype with a compact structure, easy and low cost fabrication process can provide high-precision adjustment within a certain range. The presented device exhibits well zooming characteristic and stability in the experiment, which also realizes the successful application of piezoelectric motor in the liquid-lens. It shows greatly potential in the adaptive eyeglasses, and may be employed as the mobile system in the near future.

Asphalt concrete pavement has a wide range of applications in the construction of high-grade highways. Asphalt concrete pavement has elastic properties, and its viscoelasticity and viscoplasticity are obviously affected by temperature. To determine whether a structure can continue to be used safely, it is most important to determine whether microscopic or macroscopic cracks present in the structure continue to propagate and cause structural failure. The purpose of this study was to study the effects of different ambient temperatures and mobile vehicles on the stress around the crack tip and the propagation path of different types of asphalt pavements. Based on the theory of fracture mechanics and viscoelasticity, this work studies the problem of crack propagation from a macroscopic perspective. It proposes to use the finite element method to analyze the crack problem in the pavement structure. With the help of ABAQUS software, a curved beam model with cracks was established for calculation, and moving loads and ambient temperature fields were added for analysis. The experimental results in this study show that with the decrease in the ambient temperature, the stress at the crack tip increases continuously. As the analysis time increases, the stress also increases. When the crack is smaller, the stress value at the tip is larger. When a = 15 mm, the stress value at the crack tip is the largest. However, when a = 20 mm and a = 25 mm, the stress at the crack tip is significantly reduced. It shows that the crack is easier to crack when the crack value is smaller. After the crack has grown to a certain length, the growth rate will slow down.

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