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Reprogrammable 3D Mesostructures Through Compressive Buckling of Thin Films with Prestrained Shape Memory Polymer

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Acta Mechanica Solida Sinica 2018年第5期31卷 589-598页

作者： Xiaogang Guo Zheng Xu Fan Zhang Xueju Wang Yanyang Zi John A. Rogers yonggang huang Yihui Zhang Department of Engineering Mechanics Center for Mechanics and Materials and Center for Flexible Electronics Technology AML Tsinghua University Beijing 100084 China State Key Laboratory for Manufacturing and Systems Engineering School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710049 China Simpson Querrey Institute and Feinberg Medical School Center for Bio-Integrated Electronics Northwestern University Evanston IL 60208 USA Departments of Materials Science and Engineering Biomedical Engineering Chemistry Mechanical Engineering Electrical Engineering and Computer Science and Neurological Surgery Center for Bio-Integrated Electronics Simpson Querrey Institute for Nano/biotechnology Northwestern University Evanston IL 60208 USA Departments of Civil and Environmental Engineering Mechanical Engineering and Materials Science and Engineering Center for Bio-Integrated Electronics Northwestern University Evanston IL 60208 USA

The mechanically guided assembly that relies on the compressive buckling of strate- gically patterned 2D thin films represents a robust route to complex 3D mesostructures in advanced materials and even functional micro-devices. Based on this approach, formation of complex 3D configurations with suspended curvy features or hierarchical geometries remains a challenge. In this paper, we incorporate the prestrained shape memory polymer in the 2D precur- sor design to enable local rolling deformations after the mechanical assembly through compressive buckling. A theoretical model captures quantitatively the effect of key design parameters on local rolling deformations. The combination of precisely controlled global buckling and local rolling expands substantially the range of accessible 3D configurations. The combined experimental and theoretical studies over a dozen of examples demonstrate the utility of the proposed strategy in achieving complex reprogrammable 3D mesostructures.

关键词： Mechanically guided 3D assembly Reprogrammable 3D mesostructures Shapememory polymer Buckling Rolling

MECHANICS ANALYSIS OF TWO-DIMENSIONALLY PRESTRAINED ELASTOMERIC THIN FILM FOR STRETCHABLE ELECTRONICS

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Acta Mechanica Solida Sinica 2010年第6期23卷 592-599页

作者： Ming Li JianUang Xiao Jian Wu Rak-Hwan Kim Zhan Kang yonggang huang John A. Rogers State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China Departments of Civil and Environmental Engineering and Mechanical Engineering Northwestern University Evanston IL 60208 USA Department of Materials Science and Engineering Beckman Institute for Advanced Science and Technology and Frederick Seitz Materials Research Laboratory University of Illinois at Urbana-Champaign Urbana IL 61801 USA

Various methods have been developed to fabricate highly stretchable electronics. Recent studies show that over 100% two dimensional stretchability can be achieved by mesh structure of brittle functioning devices interconnected with serpentine bridges. Kim et al show that pressing down an inflated elastomeric thin film during transfer printing introduces two di- mensional prestrain, and therefore further improves the system stretchability. This paper gives a theoretical study of this process, through both analytical and numerical approaches. Simple analytical solutions are obtained for meridional and circumferential strains in the thin film, as well as the maximum strain in device islands, which all agree reasonably well with finite element analysis.

关键词： stretchable electronics shell soft materials

Advanced therapies for congenital biliary tract malformation:From bench to bedside

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iLIVER 2022年第3期1卷 159-168页

作者： Yixuan Shao Xinyu Yang Hao Chen Di Lu yonggang huang Xiao Xu People's Hospital Zhejiang University School of MedicineHangzhou310006China Department of Hernia and Abdominal Wall Surgery Affiliated Hangzhou First People's HospitalZhejiang University School of MedicineHangzhouChina Institute of Organ Transplantation Zhejiang UniversityHangzhou310003China Westlake Laboratory of Life Sciences and Biomedicine Hangzhou310024China

Congenital biliary tract malformations are a series of rare but extremely serious diseases that mainly include biliary atresia and biliary hypoplasia(referred to as Alagille syndrome).The rapid progression of biliary atresia and Alagille syndrome results in jaundice,cholestatic liver disease,cirrhosis,and even liver *** most cases,supportive or clinically specific therapies cannot achieve satisfactory ***,liver transplantation(especially living donor liver transplantation)may be *** many studies have elucidated the role of genetic factors and the molecular mechanism of congenital biliary tract malformations,experimental therapies such as organoid transplantation,cell therapy,and immunotherapy have been proved to be *** advanced methods have shown outstanding advantages,particularly in patients with end-stage biliary tract malformations,surgery failure,and other problems that cannot be solved by conventional *** review article discusses the potential pathogenesis of and promising therapeutic strategies for biliary tract malformations.

关键词： Biliary tract malformation Biliary atresia Alagille syndrome Pediatric liver transplantation Organoid Immunotherapy

Controlled mechanical assembly of complex 3D mesostructures and strain sensors by tensile buckling

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npj Flexible Electronics 2018年第1期2卷 120-126页

作者： Xiaogang Guo Xueju Wang Dapeng Ou Jilong Ye Wenbo Pang yonggang huang John A.Rogers Yihui Zhang Department of Engineering Mechanics Center for Mechanics and Materials and Center for Flexible Electronics TechnologyAMLTsinghua University100084 BeijingPeople’s Republic of China Department of Materials Science and Engineering Northwestern UniversityEvanstonIL 60208USA State Key Laboratory of Tribology Tsinghua University100084 Beijing People’s Republic of China Center for Nano and Micro Mechanics Tsinghua University100084 Beijing People’s Republic of China Departments of Civil and Environmental Engineering Mechanical Engineeringand Materials Science and EngineeringNorthwestern UniversityEvanstonIL 60208USA Departments of Materials Science and Engineering Biomedical EngineeringNeurological SurgeryChemistryMechanical EngineeringElectrical Engineering and Computer ScienceCenter for Bio-Integrated ElectronicsSimpson Querrey Institute for BioNanotechnologyNorthwestern UniversityEvanstonIL 60208USA

Recent research establishes methods of controlled mechanical assembly as versatile routes to three-dimensional(3D)mesostructures from patterned 2D films,with demonstrated applicability to a broad range of materials(e.g.,semiconductors,polymers,metals,and their combinations)and length scales(e.g.,from sub-microscale to centimeter scale).Previously reported schemes use pre-stretched elastomeric substrates as assembly platforms to induce compressive buckling of 2D precursor structures,thereby enabling their controlled transformation into 3D ***,we introduce tensile buckling as a different,complementary strategy that bypasses the need for a pre-stretched platform,thereby simplifying the assembly process and opening routes to additional classes of 3D geometries unobtainable with compressive buckling.A few basic principles in mechanics serve as guidelines for the design of 2D precursor structures that achieve large out-of-plane motions and associated 3D transformations due to tensile *** and computational studies of nearly 20 examples demonstrate the utility of this approach in the assembly of complex 3D mesostructures with characteristic dimensions from micron to millimeter *** results also establish the use of nonlinear mechanics modeling as a mechanism for designing systems that yield desired 3D geometries.A strain sensor that offers visible readout and large detectable strain range through a collection of mechanically triggered electrical switches and LEDs serves as an application example.

关键词： strain buckling thereby

Recent progress of morphable 3D mesostructures in advanced materials

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Journal of Semiconductors 2020年第4期41卷 53-65页

作者： Haoran Fu Ke Bai yonggang huang Yihui Zhang Institute of Flexible Electronic Technology of Tsinghua ZhejiangJiaxing 314006China Center for Mechanics and Materials and Center for Flexible Electronics Technology AMLDepartment of Engineering MechanicsTsinghua UniversityBeijing 100084China Departments of Civil and Environmental Engineering Mechanical Engineeringand Materials Science and EngineeringNorthwestern UniversityEvanstonIL60208USA

Soft robots complement the existing efforts of miniaturizing conventional,rigid robots,and have the potential to revolutionize areas such as military equipment and biomedical *** type of system can accomplish tasks in complex and time-varying environments through geometric reconfiguration induced by diverse external stimuli,such as heat,solvent,light,electric field,magnetic field,and mechanical *** to achieve reconfigurable mesostructures are essential to the design and fabrication of soft *** studies mainly focus on four key aspects:reconfiguration mechanisms,fabrication schemes,deformation control principles,and practical *** review presents a detailed survey of methodologies for morphable mesostructures triggered by a wide range of stimuli,with a number of impressive examples,demonstrating high degrees of deformation complexities and varied *** latest progress based on the development of new materials and unique design concepts is *** outlook on the remaining challenges and open opportunities is provided.

关键词： morphable mesostructures reconfiguration stimuli

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Foreword

Theoretical & Applied Mechanics Letters 2011年第1期1卷 3-4页

作者： Editors-in-Chief: Jiachun Li and yonggang huang

The inauguration issue of Theoretical and Applied Mechanics Letter (TAML) finally appears at the beginning of 2011,after more than one year of planning and *** letter-type journal aims at rapid publication of mechanics-related *** few mechanics journals publish letter-type *** is the first mechanics journal to devote completely to letter-type articles such that new ideas,discoveries

关键词： TAML Foreword

大挠度欧拉梁三参数曲率模型及其在平面柔顺机构中的应用

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机械工程学报 2021年第13期57卷 144-152页

作者：谢丹黄勇刚西南大学工程技术学院重庆400715 重庆工商大学制造装备机构设计与控制重庆市重点实验室重庆400067

提出了一种基于二次Bernstein多项式的平面大挠度欧拉梁三参数曲率模型。三个曲率参数视为描述梁平衡位形的广义坐标,应用微分几何曲线论基本定理建立梁弯曲的转角方程和积分形式的挠曲线方程,基于虚功原理导出了以三个曲率参数为基本... 详细信息

提出了一种基于二次Bernstein多项式的平面大挠度欧拉梁三参数曲率模型。三个曲率参数视为描述梁平衡位形的广义坐标,应用微分几何曲线论基本定理建立梁弯曲的转角方程和积分形式的挠曲线方程,基于虚功原理导出了以三个曲率参数为基本未知量的平面欧拉梁大挠度弯曲的几何非线性平衡方程,并给出了采用高斯积分近似以及牛顿-拉弗森迭代法的数值计算格式。通过末端载荷状态下的悬臂直梁、曲梁的大挠度变形计算,以及对一种典型的平面曲柄摇杆柔顺机构的详细建模分析,验证了三参数曲率模型方法的高精度、高计算效率和对曲梁的通用性以及变形度量呈现的直观性和丰富性,结果表明该方法在柔顺机构设计和分析中具有明显优势和广阔的应用前景。

关键词：欧拉梁大挠度曲率参数化模型平面柔顺机构

平面柔顺机构大挠度弹性静力学分析的低维参数化曲率模型

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中国科学：技术科学 2022年第4期52卷 565-584页

作者：黄勇刚谢丹重庆工商大学制造装备机构设计与控制重庆市重点实验室重庆400067 西南大学工程技术学院重庆400715

针对以均质细长弹性梁为柔性构件的平面柔顺机构,通过采用Bernstein多项式逼近柔性梁弯曲曲率,提出了一种适用于大挠度强几何非线性弹性静力学分析的低维参数化曲率模型,并给出了基于高斯积分和牛顿拉弗森迭代的数值求解算法.该建模方... 详细信息

针对以均质细长弹性梁为柔性构件的平面柔顺机构,通过采用Bernstein多项式逼近柔性梁弯曲曲率,提出了一种适用于大挠度强几何非线性弹性静力学分析的低维参数化曲率模型,并给出了基于高斯积分和牛顿拉弗森迭代的数值求解算法.该建模方法的特点是直接以柔性梁弯曲应变即曲率为基本未知场函数,以Bernstein多项式试函数的待定系数为基本未知量,基于最小总势能原理建立系统的几何非线性静力平衡方程.因而避免了传统基于位移的建模求解算法通过求导计算弯曲应变能引入的数值误差,并降低了试函数的光滑性要求,建模精度高、数值计算收敛速度快且直曲梁通用.同时所求参数化曲率解与坐标系无关,具有丰富的几何和力学意义,既能实现刚体位移和柔体变形的统一建模,又能高效呈现细长梁大挠度弯曲复杂、丰富的变形信息.通过多个算例的建模分析,数值计算结果充分证明了本文方法的有效性和优越性.

关键词：柔顺机构几何非线性 Bernstein多项式曲率逼近参数化模型

Internal resonance of single-walled carbon nanotubes

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Internal resonance of single-walled carbon nanotubes