No abstract

Deployable flexible displays attract a great attention recently. The flexible display used on electronic equipment have been developed, which can deploy to reveal a much larger screen or rolled up. However, one of major problems is its actuation of deployment and fixture. In this paper, a deployable display actuated by the SMP actuator is proposed. The shape memory polymer (SMP) actuator, which is considered to be attached to the back side of a flexible display, is used to deploy and fix the flexible display. A new method of laser-induced actuation of SMP actuator is investigated. By this method, the SMP can be induced by infrared light transmitted through a treated optical fiber embedded in the actuator.

To investigate the law and mechanism of the effect of oil supply (initial oil film thickness) on the friction state of the micro-texture surface of the sliding guide. The friction and wear experiment of pin-slider surface contact is carried out to study the influence law of initial oil film thickness on friction coefficient, contact surface temperature, and lubrication state at different velocities. This experiment reveals the wear mechanism of the micro-texture surface under different initial oil film thickness, and establishes the lubrication state control model of the micro-texture surface. The results show that the velocity and initial oil film thickness have a more significant effect on the friction properties of the micro-texture surface. When the velocity is less than 0.06 m/s, the contact surface has been in the semi-dry friction state with the initial oil film thickness increases, the COF decreases by up to 13.32%, and the micro-textured surface produces abrasive wear, adhesive wear, and fatigue wear. When the velocity is more significant than 0.06 m/s, as the initial oil film thickness increases, the contact surface transits from the semi-dry friction state to the boundary lubrication state, and the COF decreases by up to 44.96%. When the velocity increases to 0.18 m/s and the initial oil film thickness is more significant than 19.8 µm, the micro-texture has a hydrodynamic pressure effect and the contact surface in the mixed lubrication state. The wear surface of the micro-texture has only slight abrasive wear, and the COF decreases by 64.07% at the highest. The study lays the theoretical foundation for the control of the lubrication state of the sliding guide surface to improve the sliding guide motion accuracy and service life.

When subject to an electric field, a dielectric elastomer (DE) deforms, possibly straining over 100%. Due to their distinctive mechanical properties, the DEs are being developed as actuators for broad applications, such as armaria, adaptive optics, and robots. According to a method to study instabilities of DE films proposed by Tommasi et al, this paper focuses on analyzing wrinkling and pull-in instabilities of circular dielectric elastomer actuators in order to guide the design of actuators conveniently and directly. Based on simple geometrical and material assumptions, the authors consider the effects of pre-stretch, the size of activated region and material model, which are all crucial in technological applications of DEs. A valid analytical method is used to describe the occurrence of wrinkling and pull-in, which gives clear physical interpretations of these failure mechanisms. As a result, this paper gives a series of critical parameters corresponding to instabilities in different pre-stretch values and the optimal pre-stretch values for some needs. They agree with the experiments well. dielectric elastomer (DE), instability, wrinkling, pull-in, actuators

No abstract