Thermally responsive liquid crystal elastomers (LCEs) hold great promise in applications of soft robots and actuators because of the induced size and shape change with temperature. Experiments have successfully demons...Thermally responsive liquid crystal elastomers (LCEs) hold great promise in applications of soft robots and actuators because of the induced size and shape change with temperature. Experiments have successfully demonstrated that the LCE based bimorphs can be effective soft robots once integrated with soft sensors and thermal actuators. Here, we present an analytical transient thermo-mechanical model for a bimorph structure based soft robot, which consists of a strip of LCE and a thermal inert polymer actuated by an ultra-thin stretchable open-mesh shaped heater to mimic the unique locomotion behaviors of an inchworm. The coupled mechanical and thermal analysis based on the thermo-mechanical theory is carried out to underpin the transient bending behavior, and a systematic understanding is therefore achieved. The key analytical results reveal that the thickness and the modulus ratio of the LCE and the inert polymer layer dominate the transient bending deformation. The analytical results will not only render fundamental understanding of the actuation of bimorph structures, but also facilitate the rational design of soft robotics.展开更多
The morphology of glacier is a key factor impacting the glacier mass redistributions.High-resolution digital elevation models(DEMs)provide a reliable method to explore the vertical characteristics of glacier surface e...The morphology of glacier is a key factor impacting the glacier mass redistributions.High-resolution digital elevation models(DEMs)provide a reliable method to explore the vertical characteristics of glacier surface elevation changes in different types.Using topographic maps from 1969 and Shuttle Radar Topography Mission(SRTM)data acquired in 2000,we calculated the surface elevation changes for 18 glaciers to generate vertical profiles of elevation difference(VPED)in the Dongkemadi region,central Tibetan Plateau.The results showed that the VPHDs vary highly among different glacier types.For valley glaciers,surface thinning at middle elevations is less than that at higher and lower elevations;for cirque glaciers,however,the maximum surface decline occurred in the middle section;whereas hanging glaciers experienced progressively less surface lowering with increasing elevation.Glacier geometry directly affects ice dynamics,which in turn dictates the VPEDs of specific glaciers.This regulation of glacier evolution can be applied to project how valley glaciers might eventually assume the VPEDs of cirque and hanging glaciers due to ongoing warming.展开更多
基金Project supported by the National Basic Research Program(No.2015CB351901)the National Natural Science Foundation of China(Nos.11372272,11622221,11621062,11502009,and 11772030)+2 种基金the Doctoral New Investigator Grant from American Chemical Society Petroleum Research Fund of the National Science Foundation(Nos.1509763 and 1554499)the Opening Fund of State Key Laboratory for Strength and Vibration of Mechanical Structures,Xi’an Jiaotong University(No.SV2018-KF-13)the Fundamental Research Funds for the Central Universities(No.2017XZZX002-11)
文摘Thermally responsive liquid crystal elastomers (LCEs) hold great promise in applications of soft robots and actuators because of the induced size and shape change with temperature. Experiments have successfully demonstrated that the LCE based bimorphs can be effective soft robots once integrated with soft sensors and thermal actuators. Here, we present an analytical transient thermo-mechanical model for a bimorph structure based soft robot, which consists of a strip of LCE and a thermal inert polymer actuated by an ultra-thin stretchable open-mesh shaped heater to mimic the unique locomotion behaviors of an inchworm. The coupled mechanical and thermal analysis based on the thermo-mechanical theory is carried out to underpin the transient bending behavior, and a systematic understanding is therefore achieved. The key analytical results reveal that the thickness and the modulus ratio of the LCE and the inert polymer layer dominate the transient bending deformation. The analytical results will not only render fundamental understanding of the actuation of bimorph structures, but also facilitate the rational design of soft robotics.
基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20060201,XDA19070302)the National Natural Science Foundation of China(41801035,41601080)The Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0201).
文摘The morphology of glacier is a key factor impacting the glacier mass redistributions.High-resolution digital elevation models(DEMs)provide a reliable method to explore the vertical characteristics of glacier surface elevation changes in different types.Using topographic maps from 1969 and Shuttle Radar Topography Mission(SRTM)data acquired in 2000,we calculated the surface elevation changes for 18 glaciers to generate vertical profiles of elevation difference(VPED)in the Dongkemadi region,central Tibetan Plateau.The results showed that the VPHDs vary highly among different glacier types.For valley glaciers,surface thinning at middle elevations is less than that at higher and lower elevations;for cirque glaciers,however,the maximum surface decline occurred in the middle section;whereas hanging glaciers experienced progressively less surface lowering with increasing elevation.Glacier geometry directly affects ice dynamics,which in turn dictates the VPEDs of specific glaciers.This regulation of glacier evolution can be applied to project how valley glaciers might eventually assume the VPEDs of cirque and hanging glaciers due to ongoing warming.
