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Mechanical properties of silicon nanobeams with an undercut evaluated by combining the dynamic resonance test and finite element analysis 被引量:2
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作者 张加宏 冒晓莉 +4 位作者 刘清惓 顾芳 李敏 刘恒 葛益娴 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第8期330-338,共9页
Mechanical properties of silicon nanobeams are of prime importance in nanoelectromechanical system applications. A numerical experimental method of determining resonant frequencies and Young's modulus of nanobeams by... Mechanical properties of silicon nanobeams are of prime importance in nanoelectromechanical system applications. A numerical experimental method of determining resonant frequencies and Young's modulus of nanobeams by combining finite element analysis and frequency response tests based on an electrostatic excitation and visual detection by using a laser Doppler vibrometer is presented in this paper. Silicon nanobeam test structures are fabricated from silicon-oninsulator wafers by using a standard lithography and anisotropic wet etching release process, which inevitably generates the undercut of the nanobeam clamping. In conjunction with three-dimensional finite element numerical simulations incorporating the geometric undercut, dynamic resonance tests reveal that the undercut significantly reduces resonant frequencies of nanobeams due to the fact that it effectively increases the nanobeam length by a correct value △L, which is a key parameter that is correlated with deviations in the resonant frequencies predicted from the ideal Euler-Bernoulli beam theory and experimentally measured data. By using a least-square fit expression including △L, we finally extract Young's modulus from the measured resonance frequency versus effective length dependency and find that Young's modulus of a silicon nanobeam with 200-nm thickness is close to that of bulk silicon. This result supports that the finite size effect due to the surface effect does not play a role in the mechanical elastic behaviour of silicon nanobeams with thickness larger than 200 nm. 展开更多
关键词 silicon nanobeams with undercut mechanical properties mechanical testing finite element method
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Research on the mechanical property test of a new high-strength metal bolt
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作者 SHI Jian-jun MA Nian-jie 《Journal of Coal Science & Engineering(China)》 2011年第4期393-396,共4页
In order to study how to improve the overall performance of the operational metal bolt, based on the production process of an ordinary metal bolt used in understructure engineering, this paper focused on the existing ... In order to study how to improve the overall performance of the operational metal bolt, based on the production process of an ordinary metal bolt used in understructure engineering, this paper focused on the existing problems of ordinary metal bolts identified by some survey and analysis. The results show that the structure of operational metal bolts is so unrea- sonable that the bolt tail is easily fractured by low load capacity. Furthermore, a new type of strong big-end metal bolt and its heat treatment and roughing processing technology were introduced. Through bolt tensile and metallographic tests, the property of the new big-end bolt was analyzed. The new findings indicate that after a special processing, the overall strength and plasticity of the bolt is greatly improved, and the grain of the bolt tail structure is refined, which would help build up favorable working conditions for bolt tails. 展开更多
关键词 mechanical test big-end bolt processing technology microscopic test
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Chang'e 3 Lander Completed Mechanical Test
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《Aerospace China》 2012年第4期23-23,共1页
Aground firing test of the Chang'e 3 lander was conducted recently to check the mechanical performance of the spacecraft. The test was vital before the propulsion system test of the Chang'e 3 lander and was al... Aground firing test of the Chang'e 3 lander was conducted recently to check the mechanical performance of the spacecraft. The test was vital before the propulsion system test of the Chang'e 3 lander and was also a very important precondition to verify whether the propulsion system design could meet the requirements for in-orbit operation. 展开更多
关键词 test very Chang’e 3 Lander Completed mechanical test
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Mechanical properties of silicon nanobeams with an undercut evaluated by combining the dynamic resonance test and finite element analysis
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作者 张加宏 冒晓莉 +4 位作者 刘清惓 顾芳 李敏 刘恒 葛益娴 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第8期334-342,共9页
Mechanical properties of silicon nanobeams are of prime importance in nanoelectromechanical system applications.A numerical experimental method of determining resonant frequencies and Young’s modulus of nanobeams by ... Mechanical properties of silicon nanobeams are of prime importance in nanoelectromechanical system applications.A numerical experimental method of determining resonant frequencies and Young’s modulus of nanobeams by combining finite element analysis and frequency response tests based on an electrostatic excitation and visual detection by using a laser Doppler vibrometer is presented in this paper.Silicon nanobeam test structures are fabricated from silicon-oninsulator wafers by using a standard lithography and anisotropic wet etching release process,which inevitably generates the undercut of the nanobeam clamping.In conjunction with three-dimensional finite element numerical simulations incorporating the geometric undercut,dynamic resonance tests reveal that the undercut significantly reduces resonant frequencies of nanobeams due to the fact that it effectively increases the nanobeam length by a correct value △L,which is a key parameter that is correlated with deviations in the resonant frequencies predicted from the ideal Euler-Bernoulli beam theory and experimentally measured data.By using a least-square fit expression including △L,we finally extract Young’s modulus from the measured resonance frequency versus effective length dependency and find that Young’s modulus of a silicon nanobeam with 200-nm thickness is close to that of bulk silicon.This result supports that the finite size effect due to the surface effect does not play a role in the mechanical elastic behaviour of silicon nanobeams with thickness larger than 200 nm. 展开更多
关键词 silicon nanobeams with undercut mechanical properties mechanical testing finite element method
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基于全局响应面算法的Q235B钢的Johnson-Cook模型参数最优
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作者 苏绍娟 武玉杰 +4 位作者 王国回 苗哲 熊野萍 郭方昕 刘海波 《哈尔滨工程大学学报(英文版)》 CSCD 2024年第2期470-478,共9页
This study investigates the mechanical properties of Q235B steel through quasi-static tests at both room temperature and elevated temperature.The initial values of the Johnson-Cook model parameters are determined usin... This study investigates the mechanical properties of Q235B steel through quasi-static tests at both room temperature and elevated temperature.The initial values of the Johnson-Cook model parameters are determined using a fitting method.The global response surface algorithm is employed to optimize and calibrate the Johnson-Cook model parameters for Q235B steel under both room temperature and elevated temperature conditions.A simulation model is established at room temperature,and the simulated mechanical performance curves for displacement and stress are monitored.Multiple optimization algorithms are applied to optimize and calibrate the model parameters at room temperature.The global response surface algorithm is identified as the most suitable algorithm for this optimization problem.Sensitivity analysis is conducted to explore the impact of model parameters on the objective function.The analysis indicates that the optimized material model better fits the experimental values,aligning more closely with the actual test results of material strain mechanisms over a wide temperature range. 展开更多
关键词 Q235B mechanical property test Numerical simulation Johnson cook model Global response surface algorithm
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Thermal Performance Analysis of Plaster Reinforced with Raffia Vinifera Particles for Use as Insulating Materials in Building
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作者 Etienne Malbila Danielle Manuella Djouego Tagne +3 位作者 Bouto Kossi Imbga Lareba Adelaide Ouedraogo Sié Kam David Yemboini Kader Toguyeni 《Journal of Minerals and Materials Characterization and Engineering》 2024年第2期112-138,共27页
The present study focuses on the formulation of new composite consisting of plaster and raffia vinifera particle (RVP) with the purpose to reducing energy consumption. The aim of this study is to test this new compoun... The present study focuses on the formulation of new composite consisting of plaster and raffia vinifera particle (RVP) with the purpose to reducing energy consumption. The aim of this study is to test this new compound as an insulating eco-material in building in a tropical climate. The composites samples were developed by mixing plaster with raffia vinifera particles (RVP) using three different sizes (1.6 mm, 2.5 mm and 4 mm). The effects of four different RVP incorporations rates (i.e., 0wt%, 5wt%;10wt%;15wt%) on physical, thermal, mechanicals properties of the composites were investigated. In addition, the use of the raffia vinifera particles and plaster based composite material as building envelopes thermal insulation material is studied by the habitable cell thermal behavior instrumentation. The results indicate that the incorporation of raffia vinifera particle leads to improve the new composite physical, mechanical and thermal properties. And the parametric analysis reveals that the sampling rate and the size of raffia vinifera particles are the most decisive factor to impact these properties, and to decreases in the thermal conductivity which leads to an improvement to the thermal resistance and energy savings. The best improvement of plaster composite was obtained at the raffia vinifera particles size between 2.5 and 4.0 mm loading of 5wt% (C95P5R) with a good ratio of thermo-physical-mechanical properties. Additionally, the habitable cell experimental thermal behavior, with the new raffia vinifera particles and plaster-based composite as thermal insulating material for building walls, gives an average damping of 4°C and 5.8°C in the insulated house interior environment respectively for cold and hot cases compared to the outside environment and the uninsulated house interior environment. The current study highlights that this mixture gives the new composite thermal insulation properties applicable in the eco-construction of habitats in tropical environments. 展开更多
关键词 Fibres PLASTER Thermal test mechanical test Insulating Material Indoor Comfort
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Elastic modulus of claystone evaluated by nano-/micro-indentation tests and meso-compression tests 被引量:5
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作者 Christophe Auvray Noémie Lafrance Danièle Bartier 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2017年第1期84-91,共8页
Toarcian claystone such as that of the Callovo-Oxfordian is a qualified multiphase material. The claystone samples tested in this study are composed of four main mineral phases: silicates(clay minerals, quartz,feldspa... Toarcian claystone such as that of the Callovo-Oxfordian is a qualified multiphase material. The claystone samples tested in this study are composed of four main mineral phases: silicates(clay minerals, quartz,feldspars, micas)(z86%), sulphides(pyrite)(z3%), carbonates(calcite, dolomite)(z10%) and organic kerogen(z1%). Three sets of measurements of the modulus of deformability were compared as determined in(i) nanoindentation tests with a constant indentation depth of 2 mm,(ii) micro-indentation tests with a constant indentation depth of 20 mm, and(iii) meso-compression tests with a constant displacement of 200 mm. These three experimental methods have already been validated in earlier studies. The main objective of this study is to demonstrate the influence of the scaling effect on the modulus of deformability of the material. Different frequency distributions of the modulus of deformability were obtained at the different sample scales:(i) in nano-indentation tests, the distribution was spread between 15 GPa and 90 GPa and contained one peak at34 GPa and another at 51 GPa;(ii) in the micro-indentation tests, the distribution was spread between 25 GPa and 60 GPa and displayed peaks at 26 GPa and 37 GPa; and(iii) in the meso-compression tests, a narrow frequency distribution was obtained, ranging from 25 GPa to 50 GPa and with a maximum at around 35 GPa. 展开更多
关键词 Claystone Elastic modulus Scaling effect Nano-and micro-indentation Meso-compression tests Multi-scale mechanical tests
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Study on the Effect of Surface Modification on the Mechanical and Thermal Behaviour of Flax,Sisal and Glass Fiber 被引量:2
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作者 C.M.Meenakshi A.Krishnamoorthy 《Journal of Renewable Materials》 SCIE 2019年第2期153-169,共17页
Natural fiber-reinforced hybrid composites can be a better replacement for plastic composites since these plastic composites pose a serious threat to the environment.The aim of this study is to analyze the effect of s... Natural fiber-reinforced hybrid composites can be a better replacement for plastic composites since these plastic composites pose a serious threat to the environment.The aim of this study is to analyze the effect of surface modification of the natural fibers on the mechanical,thermal,hygrothermal,and water absorption behaviors of flax,sisal,and glass fiber-reinforced epoxy hybrid composites.The mechanical properties of alkaline treated sisal and flax fibers were found to increase considerably.Tensile,flexural and impact strength of glass/flax-fiber-reinforced hybrid samples improved by 58%,36%,and 51%,respectively,after surface alkaline treatment.In addition,the hygrothermal analysis and water absorption capacity are studied and also the Interfacial bonding properties were analyzed using Scanning Electron Microscopic images.The thermal analysis using thermogravimetric analyzer reveals that the decomposition temperature for hybrid fiber reinforced composites are between 306 and 312℃.In conclusion,surface treatment improves the performance of natural fiber in hybrid fiber-reinforced composites,particularly flax fiber. 展开更多
关键词 Hybrid composite surface treatments mechanical testing thermal analysis hygrothermal testing water absorption SEM analysiss
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The effect of strontium on the microstructure and mechanical properties of Mg-6Al-0.3Mn-0.3Ti-1Sn 被引量:1
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作者 Huseyin Sevik S.Can Kurnaz 《Journal of Magnesium and Alloys》 SCIE EI CAS 2014年第3期214-219,共6页
In this work,the microstructural and mechanical properties of the certain magnesium-based alloys were investigated.The alloys were produced under a controlled atmosphere by a squeeze-casting process and characterized ... In this work,the microstructural and mechanical properties of the certain magnesium-based alloys were investigated.The alloys were produced under a controlled atmosphere by a squeeze-casting process and characterized by optical microscopy(OM),scanning electron microscopy(SEM),an energy-dispersive spectrometer(EDS)and X-ray diffraction(XRD)analysis.The results indicated that the addition of strontium element modified the structure and refined the grain size.The hardness and yield strength of the alloys increased continuously with increasing strontium content,while the elongation was gradually decreased.Also,the tensile strength value of the based alloy was increased by adding Sr up to 1 wt.%.After more addition of Sr,the tensile strength starts to diminish. 展开更多
关键词 Mg-Al alloy STRONTIUM MICROSTRUCTURE mechanical testing
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Influence of SBS modifiers on viscoelastic mechanical behavior of modified asphalt 被引量:1
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作者 孟勇军 张肖宁 逯彦秋 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2010年第2期157-160,共4页
In order to verify the influence of different block proportions S/B on the effect of SBS modified asphalt,the dynamic mechanical performance test and static loading test were performed on the samples composed of diffe... In order to verify the influence of different block proportions S/B on the effect of SBS modified asphalt,the dynamic mechanical performance test and static loading test were performed on the samples composed of different kinds of SBS with base asphalt. It is found that different S/B values fix on different modified effects and different viscoelastic mechanical behaviors,due to biphasic separate fabric of polybutadiene and polystyrene in SBS. In low-speed running pavement,the modified asphalt with lower S/B value shows better pavement performance,while in high-speed running pavement,the modified asphalt with higher S/B value shows better pavement performance. As far as SBS modified asphalt itself is concerned,mixing proportion impacts on resisting displacement and block proportion S/B ratio impacts on strain recovery capacity. In the case that the conditions are the same,SBS modified asphalt with different S/B values can be used for different travelling speed pavement construction demands to get an intelligent use. 展开更多
关键词 SBS modifier block proportion dynamic mechanical test static loading test
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Fast determination of meso-level mechanical parameters of PFC models 被引量:4
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作者 Guo Jianwei Xu Guoan +1 位作者 Jing Hongwen Kuang Tiejun 《International Journal of Mining Science and Technology》 SCIE EI 2013年第1期157-162,共6页
To solve the problems of blindness and inefficiency existing in the determination of meso-level mechanical parameters of particle flow code (PFC) models, we firstly designed and numerically carried out orthogonal test... To solve the problems of blindness and inefficiency existing in the determination of meso-level mechanical parameters of particle flow code (PFC) models, we firstly designed and numerically carried out orthogonal tests on rock samples to investigate the correlations between macro-and meso-level mechanical parameters of rock-like bonded granular materials. Then based on the artificial intelligent technology, the intelligent prediction systems for nine meso-level mechanical parameters of PFC models were obtained by creating, training and testing the prediction models with the set of data got from the orthogonal tests. Lastly the prediction systems were used to predict the meso-level mechanical parameters of one kind of sandy mudstone, and according to the predicted results the macroscopic properties of the rock were obtained by numerical tests. The maximum relative error between the numerical test results and real rock properties is 3.28% which satisfies the precision requirement in engineering. It shows that this paper provides a fast and accurate method for the determination of meso-level mechanical parameters of PFC models. 展开更多
关键词 Particle flow code Meso-level mechanical parameter Macroscopic property Orthogonal test Intelligent prediction
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The Mechanical and Crystallographic Evolution of Stipa tenacissima Leaves During In-Soil Biodegradation
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作者 Zakia Khelifi Mohammed Amine Allal +2 位作者 Nabil Abou-bekr Said Taibi Benoit Duchemin 《Journal of Renewable Materials》 SCIE 2018年第3期336-346,共11页
The in-soil biodegradation of Stipa tenacissima(alfa)leaves was examined.Non-linear mechanical testing was performed at various biodegradation stages.Tensile strength,loading and unloading Young’s moduli and dissipat... The in-soil biodegradation of Stipa tenacissima(alfa)leaves was examined.Non-linear mechanical testing was performed at various biodegradation stages.Tensile strength,loading and unloading Young’s moduli and dissipation energy decreased with the burial time,whereas plasticity increased.Field-emission scanning electron microscopy(FE-SEM)showed that the fracture cracks propagated in the longitudinal direction in the raw material,resulting in a fracture mode consisting of a mixture of middle lamella delamination and fiber pull-out.In contrast,the cracks were perpendicular to the stem axis in the biodegraded material,demonstrating an important strength loss of the load-bearing fibers.This strength loss was correlated with rapid cellulose degradation.A novel X-ray diffraction(XRD)model was implemented in order to take into account anisotropic size broadening.For the first time,XRD demonstrated the action of biodegradation on unrefined plant tissues under quasi in-situ conditions.Biodegradation induced a progressive loss of crystalline cellulose accompanied with anisotropic crystallite thinning. 展开更多
关键词 ALFA mechanical testing FE-SEM XRD BIODEGRADATION
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Discussion and Research on Orthopedic Biomechanics Testing Technology
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作者 Jinkui Liang Wanzong Liu +1 位作者 Xiuxiu Wang Yuanyu Li 《Journal of Clinical and Nursing Research》 2020年第6期67-70,共4页
With the continuous development of today's science and technology,orthopedic research has also achieved continuous updates in materials and machinery.In this case,the mechanics testing technology of orthopedics al... With the continuous development of today's science and technology,orthopedic research has also achieved continuous updates in materials and machinery.In this case,the mechanics testing technology of orthopedics also needs to be further updated and developed,so that it can effectively meet the requirement for today's orthopedic mechanical testing.Based on this,this article analyzes several advanced orthopedic mechanics testing techniques.It is hoped that this analysis can provide a reference for the good application and development of orthopedic mechanics testing technology. 展开更多
关键词 ORTHOPEDICS BIOMECHANICS mechanical testing testing technology
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Testing Bell’s Theorem with Circular Polarization
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作者 Richard A. Hutchin 《Optics and Photonics Journal》 2016年第11期289-297,共9页
Bell tests with entangled light have been performed many times in many ways using linear polarizers, but the same tests have never been done with a circular polarizer. Until recently there has never been a true circul... Bell tests with entangled light have been performed many times in many ways using linear polarizers, but the same tests have never been done with a circular polarizer. Until recently there has never been a true circular polarization beamsplitter—an optical component that separates light directly into left and right handed polarizations. Using a true circular polarization beamsplitter based on birefringent gratings, entangled light has been analyzed with unexpected results. 展开更多
关键词 Entangled Photons Bell’s Theorem Circular Polarization tests of Quantum Mechanics
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Twin-twin geometric structure effect on the twinning behavior of an Mg-4Y-3Nd-2Sm-0.5Zr alloy traced by quasi-in-situ EBSD
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作者 Yunwei Gui Quanan Li +1 位作者 Yibei Xue Lingxiao Ouyang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第4期1381-1392,共12页
We studied the microstructure evolution of Mg-4Y-3Nd-2Sm-0.5Zr alloy by quasi-in-situ electron backscatter diffraction(EBSD)along with several strains under compression tests,which provided direct evidence for the inf... We studied the microstructure evolution of Mg-4Y-3Nd-2Sm-0.5Zr alloy by quasi-in-situ electron backscatter diffraction(EBSD)along with several strains under compression tests,which provided direct evidence for the influence of different twin-twin geometric structure on the twinning behavior.The results showed that the mechanical properties of the alloy were higher than traditional magnesium alloys(the maximum compressive strength reaches 402.5 MPa)due to the strengthening effect of Sm and Nd elements addition on solution strengthening,precipitation strengthening,and grain refinement.Combined with the quasi-in-situ EBSD technique,two different twin-twin geometric structures,‘parallel structure’and‘cross structure’,were observed directly in the alloy.In the later stage of deformation,for‘parallel structure’,residual stress and a large number of dislocations mainly existed in the twin boundary and tip position.For the‘cross structure’,there was a lot of dislocation density in the interior of twins after fusion.The twin growth rate of‘parallel structure’was much faster than that of‘cross structure’because the stress of twins was mainly concentrated on the tip of twin.When the movement for the tip of twin was blocked,the growth rate of twin would be obviously decreased.Moreover,the‘cross structure’was easy to produce closed space.Due to the constraints of surrounding twins,the confined space was easy to stress concentration,thus inhibiting the growth of twins.At the same time,the‘cross structure’of twins needed a more external force to continue to deform,which also served as a strengthening structure. 展开更多
关键词 Mg-RE alloy mechanical testing TWINNING Quasi-in-situ EBSD
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Geometrical textures of faults,evolution of physical field and instability characteristics 被引量:6
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作者 马瑾 马胜利 +3 位作者 刘力强 邓志辉 马文涛 刘天昌 《Acta Seismologica Sinica(English Edition)》 CSCD 1996年第2期261-269,共9页
The spatial and temproal evolution of strain. fault displacement and acoustic emissions during deformation of fault systems with different geometrical textures are studied experimentally under biaxial compresison, and... The spatial and temproal evolution of strain. fault displacement and acoustic emissions during deformation of fault systems with different geometrical textures are studied experimentally under biaxial compresison, and the characteristics of typical instability events are analysed. The results show that fault systems with different geometrical textures have different evolutional images of physical field during deformation. Based on the characteristics of physical field and the deformation mechanism, various types of instability - two types of stick-slip, fracturing type and mixed type instability can be recognized. Different types of instability differ clearly in their precursors, and the instability type is closely related with the geometrical texture and the deformation stage of the fault system. Therefore, it is very significant for earthquake prediction and precursor analysis to investigatethe geometrical textures of natural active faults. 展开更多
关键词 rock mechanical test fault complex acoustic emission strain fault displacement.
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Model of coupled gas flow and deformation process in heterogeneous coal seams and its application 被引量:8
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作者 ZHANG Chun-hui ZHAO Quan-sheng YU Yong-jiang 《Journal of Coal Science & Engineering(China)》 2011年第1期76-80,共5页
The heterogeneity of coal was studied by mechanical tests. Probability plots of experimental data show that the mechanical parameters of heterogeneous coal follow a Weibull distribution. Based on elasto-plastic mechan... The heterogeneity of coal was studied by mechanical tests. Probability plots of experimental data show that the mechanical parameters of heterogeneous coal follow a Weibull distribution. Based on elasto-plastic mechanics and gas dynamics, the model of coupled gas flow' and deformation process of heterogeneous coal was presented and the effects of heterogeneity of coal on gas flow and failure of coal wcrc investigated. Major findings include: The effect of the heterogeneity of coal on gas flow and mechanical thilure of coal can be considered by the model in this paper. Failure of coal has a great effect on gas flow. 展开更多
关键词 HETEROGENEITY Weibull distribution coupled model mechanical tests
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A Review on Friction Stir Welding of Steels 被引量:3
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作者 Dhanesh G Mohan ChuanSong Wu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第6期195-223,共29页
Friction Stir Welding(FSW)is the most promising solid-state metals joining method introduced in this era.Compared to the conventional fusion welding methods,this FSW can produce joints with higher mechanical and metal... Friction Stir Welding(FSW)is the most promising solid-state metals joining method introduced in this era.Compared to the conventional fusion welding methods,this FSW can produce joints with higher mechanical and metallurgi-cal properties.Formerly,FSW was adopted for low melting metals like aluminum alloys.In recent years it has made significant progress in friction stir welding of steels since unfavourable phase transformations occurred in welds due to the melting of the parent and filler metals in fusion welding can be eliminated.The main advantage of FSW over traditional fusion welding is the reduction in the heat-affected zone(HAZ),and the joints exhibit excellent mechanical and corrosion resistance properties.This article reviews the progress in the relevant issues such as the FSW tool mate-rials and tool profiles for joining steels,microstructure and mechanical properties of steels joints,special problems in joining dissimilar steels.Moreover,in-situ heating sources was used to overcome the main limitations in FSW of hard metals and their alloys,i.e.,tool damages and insufficient heat generation.Different in-situ heating sources like laser,induction heat,gas tungsten arc welding assisted FSW for various types of steels are introduced in this review.On the basis of the up-to-date status,some problems that need further investigation are put forward. 展开更多
关键词 Friction stir welding STEELS MICROSTRUCTURE mechanical testing Hybrid welding
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Non-contact tensile viscoelastic characterization of microscale biological materials 被引量:3
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作者 Yuhui Li Yuan Hong +7 位作者 Guang-Kui Xu Shaobao Liu Qiang Shi Deding Tang Hui Yang Guy M.Genin Tian Jian Lu Feng Xu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2018年第3期589-599,共11页
Many structures and materials in nature and physiology have important "meso-scale" structures at the micron lengthscale whose tensile responses have proven difficult to characterize mechanically. Although techniques... Many structures and materials in nature and physiology have important "meso-scale" structures at the micron lengthscale whose tensile responses have proven difficult to characterize mechanically. Although techniques such as atomic force microscopy and micro- and nano-identation are mature for compression and indentation testing at the nano-scale, and standard uniaxial and shear rheometry techniques exist for the macroscale, few techniques are applicable for tensile-testing at the micrometre-scale, leaving a gap in our understanding of hierarchical biomaterials. Here, we present a novel magnetic mechanical testing (MMT) system that enables viscoelastic tensile testing at this critical length scale. The MMT system applies non-contact loading, avoiding gripping and surface interaction effects. We demonstrate application of the MMT system to the first analyses of the pure tensile responses of several native and engineered tissue systems at the mesoscale, showing the broad potential of the system for exploring micro- and meso-scale analysis of structured and hierarchical biological systems. 展开更多
关键词 mechanical testing Hierarchical biomaterials Non-contact actuation Microscale analysis
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Atomic-scale observation of the deformation and failure of diamonds by in-situ double-tilt mechanical testing transmission electron microscope holder 被引量:2
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作者 Yizhi Zhang Yeqiang Bu +4 位作者 Junquan Huang Tianye Jin Anmin Nie Hongtao Wang Yongjun Tian 《Science China Materials》 SCIE EI CSCD 2020年第11期2335-2343,共9页
In-situ transmission electron microscopy(TEM)has been demonstrated to be a powerful method in resolving challenging problems such as interactions among various defects.To take advantage of the atomic resolution of adv... In-situ transmission electron microscopy(TEM)has been demonstrated to be a powerful method in resolving challenging problems such as interactions among various defects.To take advantage of the atomic resolution of advanced TEMs,a compact five-degree-of-freedom nanomanipulator was integrated with an indenter that was made of nanotwinned diamonds,for both the in-situ mechanical testing and double tilting of TEM samples.As a demonstration,in-situ bending tests were performed on the?111?,?110?and?100?single-crystal diamond needles.The tests revealed the{111}cleavage to be the dominant failure mode.The in-situ indentation on a diamond nanoplate led to curved cracks consisting of nanometer-scale steps,which were identified to be atomic flat{111}facets.The atomic-scale observation of the deformation and failure of diamonds demonstrated the stability of the entire system and the durability of the indenter.We expect that more delicate research can be carried out by means of this holder in the near future,including in-situ stimulation,atomic characterization,and tomography. 展开更多
关键词 mechanical testing holder double tilt DIAMOND in situ TEM TOMOGRAPHY
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