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Soft pneumatic actuators by digital light processing combined with injection-assisted post-curing

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Applied Mathematics and Mechanics(English Edition) 2021年第2期42卷 159-172页

作者： Qiang ZHANG Shayuan WENG zeang zhao H.J.QI Daining FANG State Key Laboratory for Turbulence and Complex System College of EngineeringPeking UniversityBeijing 100871China College of Aerospace Engineering Chongqing UniversityChongqing 400044China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China The George W.Woodruff School of Mechanical Engineering Georgia Institute of TechnologyAtlantaGA 30332U.S.A.

The soft robotics display huge advantages over their rigid counterparts when interacting with living organisms and fragile *** one of the most efficient actuators toward soft robotics,the soft pneumatic actuator(SPA)can produce large,complex responses with utilizing pressure as the only input *** this work,a new approach that combines digital light processing(DLP)and injection-assisted post-curing is proposed to create SPAs that can realize different *** enable this,we develop a new class of photo-cross linked elastomers with tunable mechanical properties,good stretchability,and rapid curing *** carefully designing the geometry of the cavities embedded in the actuators,the resulting actuators can realize contracting,expanding,flapping,and twisting *** addition,we successfully fabricate a soft self-sensing bending actuator by injecting conductive liquids into the three-dimensional(3D)printed actuator,demonstrating that the present method has the potential to be used to manufacture intelligent soft robotic systems.

关键词： soft pneumatic actuator(SPA) digital light processing(DLP) injectionassisted post-curing three-dimensional(3D)printing

Stiffness and toughness of soft/stiff suture joints in biological composites

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Applied Mathematics and Mechanics(English Edition) 2022年第10期43卷 1469-1484页

作者： Dong WU Yixing HUANG Ming LEI zeang zhao Xiaogang GUO Daining FANG State Key Laboratory for Turbulence and Complex Systems&Center for Applied Physics and Technology College of EngineeringPeking UniversityBeijing 100871China Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China

Biological composites can overcome the conflict between strength and toughness to achieve unprecedented mechanical properties in engineering *** suture joint,as a kind of heterogeneous architecture widely existing in biological tissues,is crucial to connect dissimilar components and to attain a tradeoff of all-sided functional ***,the suture joints have attracted many researchers to theoretically investigate their mechanical ***,most of the previous models focus on the sutural interface between two chemically similar stiff phases with(or without)a thin adhesive layer,which are under the framework of linear elasticity and small ***,a general model based on the finite deformation framework is proposed to explore the stiffness and toughness of chemically dissimilar suture joints connecting soft and stiff *** tension tests are conducted to investigate the tensile response of the suture joints,and finite element simulations are implemented to explore the underlying mechanisms,considering both material nonlinearity and cohesive properties of the *** failure modes are quantitively captured by our *** stored elastic energy in the soft phase competes with the energy dissipation due to the interface debonding,which controls the transition among different failure *** toughness of the suture joints depends on not only the intrinsic strengths of the constituent materials and their cohesive strength,but also the interfacial *** work provides the structureproperty relationships of the soft/stiff suture joints and gives a foundational guidance of mechanical design towards high-performance bioinspired composites.

关键词： suture joint biological composite finite deformation toughness

A temperature/strain-rate-dependent finite deformation constitutive and failure model for solid propellants

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Science China(Physics,Mechanics & Astronomy) 2023年第9期66卷 63-78页

作者： Ming Lei Erhao Chen zeang zhao Lihua Wen Jinyou Xiao Xiao Hou School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China Institute of Advanced Structure Technology Beijing Institute of TechnologyBeijing 100081China China Aerospace Science and Technology Corporation Beijing 100048China

The stress-strain response under progressive damage and the ultimate failure of solid propellants are two key issues affecting the integrity of solid rocket *** research primarily focused on the progressive damage in solid propellants during production and ***,they failed to take the temperature/strain-rate-dependent ultimate failures into *** failure strains of solid propellants are experimentally observed to show strong temperature/strain-rate dependence and exhibit an abnormal evolution at low and high temperatures,*** increasing loading strain rate,the failure strains decrease at low temperatures near the glass transition temperature(T_g)but increase at high temperatures far above T_(g).In this study,we introduce the glassy and rubbery failure criteria based on strain energy densities at ultralow and ultrahigh temperatures,respectively,into a viscoelastic constitutive model and build a unified model for the progressive damage and the ultimate failure of solid *** the introduction of these two additional criterion parameters,the developed model can effectively predict the yield-type stress-strain responses,microscopic damage-induced volume dilatations,and temperature/strain-ratedependent ultimate failures of the solid propellants by comparing the model predictions with the experimental *** competition between the glassy failure and the rubbery failure results in the propellants exhibiting a maximum break strain near the glass transition ***,when the strain rate is increased,the propellants exhibit a predominantly glassy response,which shifts the failure envelope toward a higher *** induces an abnormal evolution of failure strains by making the propellants stretchable at high temperatures and brittle at low temperatures.

关键词： viscoelastic material polymeric material constitutive behavior fracture toughness failure envelope

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A novel hybrid design method of lattice structure based on failure mode

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Science China(Physics,Mechanics & Astronomy) 2022年第9期65卷 79-91页

作者： Chuanlei Li Junfeng Qi Panding Wang zeang zhao Zhe Wang Hongshuai Lei Shengyu Duan Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of TechnologyBeijing 100081China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Beijing Spacecrafts Beijing 100094China

Adjusting the mechanical properties of lattice structures is important for many modern application fields. In this paper, a new design method for hybrid multi-layer lattice structures was developed to improve the mechanical properties and energy absorption, by altering and suppressing the formation of the shear band. In these hybrids, all unit cells were divided into two parts:(i) diagonal unit cells and(ii) matrix unit cells. Four categories of unit cells were selected to construct the hybrid multi-layer structures. The compressive moduli, ultimate strengths, and energy absorption properties of the laser powder bed fusion(L-PBF)fabricated structures were assessed by experiments and finite element analysis(FEA). The results revealed the great impact of diagonal unit cells on the mechanical properties of the structures. Stronger diagonal unit cells than matrix unit cells led to hybrid structures with enhanced mechanical properties. Compared with a uniform body-centered cubic(BCC) lattice structure, the relative density of the lattice structure consisting of the weakest BCC matrix unit cells and strongest BFVC diagonal unit cells(coupling of BCC, FCC, and VC) exhibited an increase of 20%. The compressive modulus and ultimate strength of this structure rose by more than 200% and 90%, respectively. Two types of structures with specific properties were generated by hybrid *** first displayed higher modulus, superior strength, and elevated specific energy absorption(SEA) but lower crash load efficiency(CLE). The second illustrated simultaneously higher SEA and elevated CLE. The present results provide a new insight for improving the load-bearing and energy absorption capacities of lattice structures.

关键词： additive manufacturing lattice structure shear deformation hybrid mechanical properties

Adaptive enhancement design of triply periodic minimal surface lattice structure based on non-uniform stress distribution

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Applied Mathematics and Mechanics(English Edition) 2023年第8期44卷 1317-1330页

作者： Yijin ZHANG Bin LIU Fei PENG Heran JIA zeang zhao Shengyu DUAN Panding WANG Hongshuai LEI Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of TechnologyBeijing 100081China Beijing Institute of Astronautical Systems Engineering Beijing 100076China

The Schwarz primitive triply periodic minimal surface(P-type TPMS)lattice structures are widely ***,these lattice structures have weak load-bearing capacity compared with other cellular *** this paper,an adaptive enhancement design method based on the non-uniform stress distribution in structures with uniform thickness is proposed to design the P-type TPMS lattice structures with higher mechanical *** types of structures are designed by adjusting the adaptive thickness distribution in the *** keeps the same relative density,and the other keeps the same of non-enhanced region *** with the uniform lattice structure,the elastic modulus for the structure with the same relative density increases by more than 17%,and the yield strength increases by more than 10.2%.Three kinds of TPMS lattice structures are fabricated by laser powder bed fusion(L-PBF)with 316L stainless steel to verify the proposed enhanced *** manufacture-induced geometric deviation between the as-design and as-printed models is measured by micro X-ray computed tomography(μ-CT)*** quasi-static compression experimental results of P-type TPMS lattice structures show that the reinforced structures have stronger elastic moduli,ultimate strengths,and energy absorption capabilities than the homogeneous P-TPMS lattice structure.

关键词： additive manufacturing(AM) triply periodic minimal surface(TPMS) enhanced design model mechanical property micro X-ray computed tomography(u-CT)

Planar bi-metallic lattice with tailorable coefficient of thermal expansion

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Acta Mechanica Sinica 2022年第7期38卷 192-200,I0005页

作者： Mengchuan Xu zeang zhao Panding Wang Yijin Zhang Xiaogang Guo Hongshuai Lei Daining Fang Beijing Key Laboratory of Lightweight Multi-Functional Composite Materials and Structures Beijing Institute of TechnologyBeijing100081China

A mechanical metamaterial that has a tailorable coefficient of thermal expansion(CTE)is promising for guaranteeing the reliability of electrical and optical instruments under thermal *** growing research on the design and manufacturing of metamaterials with extraordinary CTEs,it remains challenging to achieve a nearly isotropic tailorable CTE while ensuring a sufficient load bearing capacity for applications,such as mechanical supporting *** this research,we propose a type of bi-metallic lattice whose CTE is artificially programmed from positive(75 ppm/K)to negative(−45 ppm/K),and whose equivalent modulus can be as high as 80 *** bi-metallic lattice with a tailorable CTE in two orthogonal directions can be readily assembled without special modifications to construct large-scale planar structures with desired isotropic CTEs.A theoretical model that considers the actual configuration of the bi-metallic joint is developed;the model precisely captures the thermal deformations of lattice structures with varied geometries and material *** by our theoretical design method,planar metallic structures that were manufactured using Al,Ti,and Invar alloy were experimentally characterized;the structures exhibited outstanding performance when compared with typical engineering materials.

关键词： Mechanical metamaterial Metallic lattice Coefficient of thermal expansion Load bearing capacity

航天器轻量化多功能结构设计与制造技术研究进展

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宇航材料工艺 2021年第4期51卷 10-22页

作者：雷红帅赵则昂郭晓岗陶然李营黄怿行赵天方岱宁北京理工大学先进结构技术研究院北京100081

轻质多功能结构是航天器装备实现轻量化的重要技术途径,本文针对航天器轻量化多功能结构设计与制造技术进行概述,重点介绍了高承载三维点阵结构、热变形稳定结构、智能折展结构、分离解锁结构、电磁隐身结构、以及复合材料新型连接技术... 详细信息

轻质多功能结构是航天器装备实现轻量化的重要技术途径,本文针对航天器轻量化多功能结构设计与制造技术进行概述,重点介绍了高承载三维点阵结构、热变形稳定结构、智能折展结构、分离解锁结构、电磁隐身结构、以及复合材料新型连接技术等方面的现状及发展趋势,浅析了航天器装备新型结构研制面临的关键技术问题。

关键词：航天器装备轻量化结构多功能结构制造技术

增材制造三维点阵结构设计、优化与性能表征方法研究进展

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航空制造技术 2022年第14期65卷 36-48,57页

作者：段晟昱王潘丁刘畅赵则昂周浩张啸雨雷红帅郭旭方岱宁北京理工大学北京100081 大连理工大学大连116023 中国空间技术研究院北京100094

增材制造技术与三维点阵结构技术是航空航天装备结构实现轻量化与多功能化的重要途径。针对增材制造三维点阵结构及其设计方法进行概述,重点介绍了增材制造三维点阵结构工程应用、轻质多功能三维点阵结构构型设计方法、三维点阵结构多... 详细信息

增材制造技术与三维点阵结构技术是航空航天装备结构实现轻量化与多功能化的重要途径。针对增材制造三维点阵结构及其设计方法进行概述,重点介绍了增材制造三维点阵结构工程应用、轻质多功能三维点阵结构构型设计方法、三维点阵结构多尺度计算方法与拓扑优化方法、增材制造三维点阵结构性能评价表征方法等方面的研究现状与进展,对增材制造三维点阵结构在材料–结构–功能一体化设计方面的发展趋势进行了展望。

关键词：增材制造(AM) 点阵结构结构设计拓扑优化性能表征

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基于SolidWorks的齿轮箱虚拟设计

煤矿机械 2011年第1期32卷 224-226页

作者：赵晓春张宝霞寸立岗马琳济南铁路局车辆段济南250001 兰州交通大学机电工程学院兰州730070

比较了虚拟设计和传统设计,阐述了虚拟设计的优点。选用Solidworks作为虚拟设计平台,对JMY240机车车轴齿轮箱进行3D建模和参数化设计,并运用Solidworks的虚拟装配功能对所建立的模型进行配合和动画仿真,完成了齿轮箱的3D实体建模和虚拟... 详细信息

比较了虚拟设计和传统设计,阐述了虚拟设计的优点。选用Solidworks作为虚拟设计平台,对JMY240机车车轴齿轮箱进行3D建模和参数化设计,并运用Solidworks的虚拟装配功能对所建立的模型进行配合和动画仿真,完成了齿轮箱的3D实体建模和虚拟装配设计,为方便、快捷、准确地研制和开发产品提供了有力的技术保障。

关键词：虚拟设计齿轮箱齿轮装配