JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
·
2021
·
IF 5.471
Jincheng Lei,Ziqian Li,Shuai Xu,Zishun Liu
Fracture is a highly nonlinear problem, especially under a large deformation in cross-linked elastomers. Existing constitutive theories and fracture models fail to predict the fracture behavior of cross-linked elastomers because of the absence of the random polymer network structure. Meanwhile, few numerical methods can present the realistic fracture process of a polymer network. In this study, we propose a mesoscopic network mechanics method to present the entire large deformation and fracture process of the polymer network in cross-linked elastomers. The microstructure of a cross-linked elastomer is abstracted as a polymer network model where nodes are referred to as crosslinkers and connections between nodes are referred to as polymer chains. A hybrid total energy form of the network model is proposed including the free energy of polymer chains and volumetric deformation energy. In addition, using a proposed stretch criterion of polymer chains to realize chain scission, this mesoscopic network mechanics method is numerically implemented by coding. Two-dimensional network models with uniform and randomly distributed chain lengths, as well as models with different types of pre-cracks, are constructed and simulated under uniaxial tension tests using our method. Our method reproduces the entire hyper-elastic large deformation and fracture process of polymer network models. The random network models show a lower Young's modulus and a less significant strain-hardening stage, indicating that the structural randomness is the primary cause of accuracy degradation for existing hyperelastic constitutive models under large deformations. The results also reveal that the structural randomness of the polymer network is a primary reason for the ductile fracture and the low notch sensitivity of cross-linked elastomers.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
Advanced Intelligent Systems
·
2020
·Vol. 2
·期 8
·2000036
·
IF 0
Guinan Chen,Zhonglin Yang,Wenwen Wang,Lili Bi,Liangjun Chen,Yongwu Peng,Changhui Ye
The ability to fabricate electrothermal actuators (ETAs) simultaneously featuring ultrafast response speed (within 0.1 s), large deformation (bending for at least 360°), high figure-of-merit (FoM, larger than 0.1%), and low driving voltage (smaller than 1 V) in a single device is extremely important and challenging for their applications in artificial muscles, switches, and microsensors for robotics and biomimetic devices. Herein, an ETA composed of a silver nanowire (AgNW) layer and an ultrathin linear low-density polyethylene (LLDPE) film with all the aforementioned features is designed. Due to the high conductivity of the AgNW layer and the great difference between the coefficients of thermal expansion of AgNW layer and LLDPE film as well as the huge change in the heat transfer coefficient between flat and rolled ETA, the obtained ETA exhibits an ultrafast response speed of 0.08 s for a bending angle of 360° with a FoM of 0.46% at a low driving voltage of 1 V, over one order of magnitude larger than those of reported ETAs. As a proof-of-concept application, the as-prepared ETAs can be used as intelligent mechanical devices with excellent performance.
研究领域:
材料科学
·
仿生学
·
机器人技术
✓ 已验证
产品关联
DOI
Nanomaterials
·
2022
·Vol. 12
·期 11
·1867
·
IF 5.719
Hexuan Yan,Luying Si,Gang Li,Lejian Zhao,Wei Luo,Huiru Ma,Jianguo Guan
The rapid and robust response to external stimulus with a large volume deformation is of huge importance for the practical application of thermo-responsive photonic crystal film (TRPCF) in actuators, colorimetric sensors, and other color-related fields. Generally, decreasing the size of thermo-responsive photonic crystals and introducing micropores are considered to be two effective approaches to improve their responsiveness. However, they usually result in a poor mechanical property, which leads to optical instability. To solve these problems, a heterogeneous thermo-responsive photonic crystal film was developed here by integrating a thermosensitive hydrogel matrix poly(N-isopropylacrylamide-co-N-methylolacrylamide) (P(NIPAM-co-NHMA)) with high-modulus, but non-thermosensitive poly(acrylic acid -co-2-hydroxyethyl methacrylate (P(AA-co-HEMA)) hydrogel-based photonic nanochains (PNCs). The as-obtained TRPCF based on PNCs (TRPCF-PNC) well combined the rapid response and improved the mechanical property. Typically, it can complete a response within 12 s from 26 to 44 °C, which was accompanied by a larger deformation of the matrix than that of the PNCs. The unique rapid thermochromic mechanism of the TRPCF-PNC is revealed here. Furthermore, it exhibits a high tensible property along the PNC-orientation direction and excellent optical stability. The response time of the TRPCF-PNC can conveniently modulate by changing the cross-linking degree of the PNCs or the content of the thermosensitive component in the matrix. The heterogeneous TRPCF-PNC is believed to have potential applications in artificial muscle and quick-response actuation devices.Keywords:thermochromic film;heterogeneous hydrogel;photonic nanochains;quick response;large deformation
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Additive Manufacturing
·
2024
·
IF 10.3
Shuhao Qi,Qin Lian,Yanlong Chen,Tao Zhou,Chuncheng Yang,Dichen Li
In the bottom-up vat photopolymerization process for ceramic materials, the as-built part is generated layer-by-layer from the bottom of the slurry vat. The separation process between the solidified layer and the bottom of the slurry vat introduces significant vertical separation forces due to various resistance forces. Particularly in fabricating large cross-section parts, larger separation forces are more prone to induce crack propagation or detachment of the as-built part from the substrate, resulting in printing failures. This study introduces a novel approach involving the application of a talcum powder-coated polydimethylsiloxane (PDMS) film to address this issue, aiming to reduce the adhesion between the PDMS film and the bottom of the slurry vat. The developed system exhibits flexible separation capabilities during the build platform's lifting process. Compared to traditional unmodified PDMS film separation systems, the modified system demonstrates an average reduction of 93% in the maximum separation force. Notably, as the cross-sectional area of the printing increases, the magnitude of the increase in maximum separation force of the modified system compared to the unmodified system drops significantly. This characteristic facilitates the successful printing of larger-sized parts. The talcum powder-coated PDMS separation system proves effective in successfully printing aviation ceramic cores, triply periodic minimal surface (TPMS) models, teeth model with a cross-sectional size of 85 mm × 65 mm in solid geometry and a bone model exceeding 150 mm in height.
研究领域:
材料科学
·
增材制造
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2019
·Vol. 30
·期 7
·1908508
·
IF 15.621
Suqian Ma,Yunpeng Zhang,Yunhong Liang,Lei Ren,Wenjing Tian,Luquan Ren
As promising candidates in the field of artificial muscles, ionic-polymer–metal composites (IPMCs) still cannot simultaneously provide large deformations and fast responses, which has limited their practical applications. In this study, to overcome this issue, a Nafion-based IPMC with high-quality metal electrodes is fabricated via novel isopropanol-assisted electroless plating. The IPMC exhibits a large tip displacement (35.3 mm, 102.3°) under a low direct-current driving voltage and ultrafast response (>10 Hz) under an alternating-current (AC) voltage. Furthermore, the simultaneous integration of a large deformation and fast response can be achieved by the IPMC under a high-frequency (19 Hz) AC voltage, where the largest bending amplitude is 5.9 mm and the highest bending speed reaches 224.2 mm s −1 (596.2° s −1 ). Additionally, the lightweight IPMC exhibits a decent load capacity and can lift objects 20 times heavier. The outstanding performances of the Nafion IPMC are demonstrated by mimicking biological motions such as petal opening/closing, tendril coiling/uncoiling, and high-frequency wing flapping. This study paves the way for the fabrication of lightweight actuators with simultaneous large displacements and fast responses for promising applications in biomedical devices and bioinspired robotics.
研究领域:
材料科学
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仿生学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2022
·
IF 10.508
Yu Peng,Kaihang Zhang,Baoyi Wu,Jianlei Lu,Yukun Jian,Yaoting Xue,Xuxu Yang,Jiawei Zhang,Tao Chen
Living organisms can generate diverse three-dimensional (3D) morphologies and programmatically regulate their morphological evolution via the neurally controlled expansion and contraction of soft tissues. Although polymeric hydrogels have been regarded as an ideal experimental platform for biomimetic morphing due to their soft-tissue-like properties, it is still a tricky problem to quantitatively design their 3D morphological evolution, especially for inert polymeric hydrogels. In this study, we developed a muscle-inspired deformation system that could programmatically regulate the morphological evolution of undeformable inert polymeric hydrogels using large-deformable hydrogels as muscles, which contained smart poly N-isopropylacrylamide (PNIPAm) microgel and could be anchored onto any hydrogels via interfacial diffusion polymerization (IDP). Moreover, by programmatically regulating the anchoring position of the large-deformable muscle, the 3D morphology of kirigami-shaped hydrogels could further evolve to obtain a more complex 3D morphology. Surprisingly, when the inert hydrogel was replaced by a shape-memory hydrogel, the 3D morphologies could be fixed and preserved for more than 1 month without any stress relaxation or swelling, even after removing the hydrogel muscle or external stimuli. Therefore, we believe that this deformation strategy will enhance our understanding of the life evolution of natural soft-wet organisms for developing intelligent soft materials such as shape-memory hydrogels, programmable deformations, and 3D biomimetic devices.
研究领域:
材料科学
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生物仿生学
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软物质物理
✓ 已验证
产品关联
DOI
高影响因子
Mechanics of Solids
·
2023
·Vol. 58
·期 3
·890-902
·
IF 0.7
Shan Yan,Zhang Qiang,Yang Qingsheng
Abstract In recent years, instrumented indentation technique has been widely applied in the mechanical characterization of hydrated soft materials such as hydrogels and bio-soft tissues. However, the indentation measurement technique and properties evaluation methods for this kind of materials undergoing large deformation have not been well developed. Applying the indentation load-relaxation experiments, this paper studied the relaxation behaviors of calcium alginate/polyacrylamide double-network hydrogels under large spherical indentation deformation. The effects of temperature on the relaxation properties of calcium alginate/polyacrylamide double-network hydrogels were also measured and evaluated. This work not only helps to improve the understanding of the relaxation properties of double-network hydrogels under large deformation conditions, but also has certain guiding significance for the development of the instrumented indentation testing technology of soft materials.
研究领域:
材料科学
·
生物力学
✓ 已验证
产品关联
DOI
高影响因子
Materials Science and Engineering B-Advanced Functional Solid-State Materials
·
2021
·
IF 4.051
Zhe Shi,An Li,Cong Zhang,Yang-Fei Zhang
Combining graphene composite with three-dimensional structure is an effective strategy to avoid the agglomeration of graphene nanosheets and significantly enhances the properties of composite at low graphene content. In this work, reduced graphene oxide coated polyurethane composite foams (RPFs) with different pore sizes were prepared by a simple and economical self-assembly method. The RPFs are found to have good structural integrity and excellent flexibility, with a remarkable ability to withstand large deformation of 90% and 3 orders of magnitude decrease of electrical resistance. The RPF composite with higher density and smaller pore size exhibits better elasticity and responsive piezoresistivity. The resistance-time curves of RPFs in compression and bending modes exhibits a quick response of loading and release procedures by 0.10 s and 0.74 s in compression, 1.14 s and 0.91 s in bending, respectively, showing a good potential application of flexible and highly sensitive strain sensors for large deformation.
研究领域:
材料科学
·
传感器技术
✓ 已验证
DOI
高影响因子
Nano Energy
·
2019
·
IF 15.548
Jingwen Liao,Yang Zou,Dongjie Jiang,Zezhi Liu,Xuecheng Qu,Zhe Li,Ruping Liu,Yubo Fan,Bojing Shi,Zhou Li,Li Zheng
Flexible and wearable electronics has presented an opportunity to evolve our society into an intelligent world. Especially for biomechanical sensing and gesture recognition, wearable devices are quite indispensable. Here, we present a nestable arched triboelectric nanogenerator (NA-TENG), which can be wore on fingers, acting as a large deflection biomechanical sensor and energy harvester . With arched structure, the sensor can detect large bending angle of fingers with good stability. Meanwhile, the NA-TENG devices can be assembled like matryoshka, which greatly increases the extensibility for optimizing output performance of the NA-TENG, and provides a convenient method to regulate characteristics of TENG devices in wearable applications.
研究领域:
生物医学工程
·
柔性电子学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
·
2025
·
IF 6
Jincheng Lei,Yuan Gao,Shuai Xu,Linchun He,Zishun Liu
Current constitutive theories and fracture models face difficulties in capturing the extremely large deformation and fracture behaviors of hydrogels, because the structural and mechanical properties of the effective polymer network dominated in hydrogels are still unknown. In this study, we propose a periodic random network (PRN) method to construct the effective polymer network model of polyacrylamide (PAAm) hydrogel from the bottom up and reveal the effect of the effective polymer network on the extremely large deformation and fracture behaviors of PAAm hydrogels. It is surprising that the PRN models determined by only three parameters capture the extremely large deformation and fracture behaviors of PAAm hydrogel in uniaxial tension experiments very well. The PRN models measure that only about 20 % of monomers and crosslinkers form the effective network in the PAAm hydrogel samples in this work, and the mean monomer number of the effective chains in PAAm hydrogels deviates a lot from that estimated by the ideal network assumption. An anisotropic damage accumulation process of PAAm hydrogel under extremely large deformation before bulk fracture is predicted by PRN models, which has been observed in previous experiments but not explained. This is the fundamental cause that the Lake-Thomas model underestimates the intrinsic fracture toughness of PAAm hydrogels very much. This work provides an insightful method to measure the structural and mechanical properties of hydrogels.
研究领域:
材料科学
·
生物力学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Baolu Shi,Yong Qin,Zhiliang Zhou,Yu Chen,Yan Zhang,Donghui Guo,Ning Zhou,Lichen Wang,Baosheng Xu
Ceramic aerogels have become the most commonly used materials in high-temperature thermal insulation systems because of their thermal stability. However, the inherent brittleness limits their application under harsh thermomechanical conditions, such as morphing aircraft and inflatable decelerators. Herein, high-temperature resistant ceramic aerogel composite metastructures with 3D large deformation by introducing the concept of origami are designed and prepared, and their mechanical and thermal properties are investigated. The prepared ceramic aerogel composite exhibits 158% ultrahigh uniaxial tensile fracture strain and remains intact after 60 cycles to 80% tensile strain, with excellent fatigue resistance. They can also achieve an unprecedented in-plane biaxial strain of 455%, and the ratio of the out-of-plane bulging height to the typical feature size is 0.94. Owing to their low thermal conductivity (0.0376 W m −1 K −1 ) and excellent thermal stability (1200 °C), the ceramic aerogel composites still maintain large-deformation performance in high-temperature environments. Thus, the large-deformation ceramic aerogel composite metastructures are suitable for complex and diverse deformation fields, addressing current limitations.
研究领域:
材料科学
·
热力学
·
纳米科技
·
复合材料工程
·
航空航天材料
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Chunbao Liu,Hui Xu,Yunhong Liang,Suqian Ma,Zhaohua Lin,Lei Ren,Zhiwu Han,Luquan Ren
Ionic-polymer metal composites (IPMCs) actuators show great potential for soft robots due to their large deformations and fast responses at low voltage. However, realizing large and stable deformation remains a challenge since the existence of back relaxation phenomena. Herein, we report high-performance IPMCs actuators fabricated via solution-casting and isopropanol-assisted electroless plating methods. The actuator exhibits extremely large bending deformation (125°) and ultrafast initial response speed (1.09 % s −1 bending strain rate) within one second of the start time under the DC voltage of 3 V. Furthermore, the actuator exhibits no significant back relaxation, even when it lifts objects 11 times heavier and holds up for more than 695 s. The outstanding properties of the actuator are demonstrated by various soft robots, including a guide-grapple robot and a microarchitecture for robotic metamaterials, and a finite element simulation approach is proposed to model the robotic metamaterials. This study offers a viable means for developing high-performance artificial muscles without back relaxation for promising applications in biomedical devices, robotic metamaterials, and soft robotics.
研究领域:
材料科学
·
机器人学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）