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Microscopic damage and dynamic mechanical properties of rock under freeze-thaw environment 被引量:25
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作者 周科平 李斌 +2 位作者 李杰林 邓红卫 宾峰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第4期1254-1261,共8页
For understanding the rock microscopic damage and dynamic mechanical properties subjected to recurrent freeze-thaw cycles, experiments for five groups of homogeneous sandstone under different freeze-thaw cycles were c... For understanding the rock microscopic damage and dynamic mechanical properties subjected to recurrent freeze-thaw cycles, experiments for five groups of homogeneous sandstone under different freeze-thaw cycles were conducted. After freezethaw, nuclear magnetic resonance(NMR) tests and impact loading tests were carried out, from which microscopic damage characteristics of sandstone and dynamic mechanical parameters were obtained. The results indicate that the porosity increases with the increase of cycle number, the rate of porosity growth descends at the beginning of freeze-thaw, yet accelerates after a certain number of cycles. The proportion of pores with different sizes changes dynamically and the multi-scale distribution of pores tends to develop on pore structure with the continuing impact of freeze-thaw and thawing. Dynamic compressive stress-strain curve of sandstone undergoing freeze-thaw can be divided into four phases, and the phase of compaction is inconspicuous compared with the static curve. Elastic modulus and dynamic peak intensity of sandstone gradually decrease with freeze-thaw cycles, while peak strain increases. The higher the porosity is, the more serious the degradation of dynamic intensity is. The porosity is of a polynomial relationship with the dynamic peak intensity. 展开更多
关键词 ROCK freeze-thaw cycle nuclear magnetic resonance(NMR) pore structure dynamic mechanical property dynamic compression stress-strain curve
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Dynamic mechanical properties and constitutive equations of 2519A aluminum alloy 被引量:10
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作者 刘文辉 何圳涛 +1 位作者 陈宇强 唐思文 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第7期2179-2186,共8页
To analyze the effects of strain rate and temperature on the flow stress of 2519A aluminum alloy, the dynamic mechanical properties of 2519A aluminum alloy were measured by dynamic impact tests and quasi-static tensil... To analyze the effects of strain rate and temperature on the flow stress of 2519A aluminum alloy, the dynamic mechanical properties of 2519A aluminum alloy were measured by dynamic impact tests and quasi-static tensile tests. The effects of strain rate and temperature on the microstructure evolution were investigated by optical microscopy (OM) and transmission electron microscopy (TEM). The experimental results indicate that 2519A aluminum alloy exhibits strain-rate dependence and temperature susceptibility under dynamic impact. The constitutive constants for Johnson--Cook material model were determined by the quasi-static tests and Hopkinson bar experiments using the methods of variable separation and nonlinear fitting. The constitutive equation seems to be consistent with the experimental results, which provides reference for mechanical characteristics and numerical simulation of ballistic performance. 展开更多
关键词 2519A aluminum alloy dynamic mechanical properties Johnson-Cook model MICROSTRUCTURE
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The Effect of Fibre Length on Flexural and Dynamic Mechanical Properties of Pineapple Leaf Fibre Composites
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作者 A.A.Mazlan M.T.H.Sultan +3 位作者 S.N.A.Safri N.Saba A.U.M.Shah M.Jawaid 《Journal of Renewable Materials》 SCIE EI 2020年第7期833-843,共11页
The present paper deals with the effect of loading different pineapple leaf fibre(PALF)length(short,mixed and long fibres)and their reinforcement for the fabrication of vinyl ester(VE)composites.Performance of PALF/VE... The present paper deals with the effect of loading different pineapple leaf fibre(PALF)length(short,mixed and long fibres)and their reinforcement for the fabrication of vinyl ester(VE)composites.Performance of PALF/VE composites was investigated through three-point bending flexural testing and viscoelastic(dynamic)mechanical properties through dynamic mechanical analysis(DMA).DMA results revealed that the long PALF/VE composites displayed better mechanical,damping factor and dynamic properties as compared to the short and mixed PALF/VE composites.The flexural strength and modulus of long PALF/VE composites were 113.5 MPa and 14.3 GPa,respectively.The storage(E′)and loss(E″)moduli increased to 2000 MPa and 225 MPa respectively for PALF/VE composites.Overall result analysis indicated that increasing the length of the reinforcement fibre results in satisfactory mechanical performance and dynamic properties of composites. 展开更多
关键词 Pineapple leaf fibre vinyl ester resin flexural strength dynamical mechanical properties damping factor
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Dynamic mechanical properties and instability behavior of layered backfill under intermediate strain rates 被引量:20
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作者 Yun-hai ZHANG Xin-min WANG +1 位作者 Chong WEI Qin-li ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第7期1608-1617,共10页
To obtain dynamic mechanical properties and failure rule of layered backfill under strain rates from10to80s-1,impactloading test on layered backfill specimens(LBS)was conducted by using split Hopkinson pressure bar sy... To obtain dynamic mechanical properties and failure rule of layered backfill under strain rates from10to80s-1,impactloading test on layered backfill specimens(LBS)was conducted by using split Hopkinson pressure bar system.The results indicatethat positive correlation can be found between dynamic compressive strength and strain rate,as well as between strength increasefactor and strain rate.Dynamic compressive strength of LBS gets higher as the arithmetic average cement-sand ratio increases.Compared with static compressive strength,dynamic compressive strength of LBS is enhanced by11%to163%.In addition,theenergy dissipating rate of LBS lies between that of corresponding single specimens,and it decreases as the average cement contentincreases.Deformation of LBS shows obvious discontinuity,deformation degree of lower strength part of LBS is generally higherthan that of higher strength part.A revised brittle fracture criterion based on the Stenerding-Lehnigk criterion is applied to analyzingthe fracture status of LBS,and the average relevant errors of the3groups between the test results and calculation results are4.80%,3.89%and4.66%,respectively. 展开更多
关键词 layered backfill specimen (LBS) split Hopkinson pressure bar (SHPB) dynamic mechanical properties damage characteristic failure criterion
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Effect of Gd content on microstructure and dynamic mechanical properties of solution-treated Mg−xGd−3Y−0.5Zr alloy 被引量:8
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作者 Xue-zhao WANG You-qiang WANG +3 位作者 Chen-bing NI Yu-xin FANG Xiao YU Ping ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第7期2177-2189,共13页
The effect of Gd content ranging from 6.5 wt.%to 8.5 wt.%on microstructure evolution and dynamic mechanical behavior of Mg−xGd−3Y−0.5Zr alloys was investigated by optical microscopy,X-ray diffraction,scanning electron... The effect of Gd content ranging from 6.5 wt.%to 8.5 wt.%on microstructure evolution and dynamic mechanical behavior of Mg−xGd−3Y−0.5Zr alloys was investigated by optical microscopy,X-ray diffraction,scanning electron microscopy and split Hopkinson pressure bar.The microstructure of as-cast Mg−xGd−3Y−0.5Zr alloys indicates that the addition of Gd can promote grain refinement in the casting.Due to the rapid cooling rate during solidification,a large amount of non-equilibrium eutectic phase Mg_(24)(Gd,Y)_(5) appears at the grain boundary of as-cast Mg−xGd−3Y−0.5Zr alloys.After solution treatment at 520℃ for 6 h,the Mg_(24)(Gd,Y)_(5) phase dissolves into the matrix,and the rare earth hydrides(REH)phase appears.The stress−strain curves validate that the solution-treated Mg−xGd−3Y−0.5Zr alloys with optimal Gd contents maintain excellent dynamic properties at different strain rates.It was concluded that the variation of Gd content and the agglomeration of residual REH particles and dynamically precipitated fine particles are key factors affecting dynamic mechanical properties of Mg−xGd−3Y−0.5Zr alloys. 展开更多
关键词 Mg−xGd−3Y−0.5Zr alloy MICROSTRUCTURE dynamic mechanical properties rare earth hydrides dynamic precipitated phase
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Combined effects of temperature and axial pressure on dynamic mechanical properties of granite 被引量:6
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作者 Tu-bing YIN Rong-hua SHU +2 位作者 Xi-bing LI Pin WANG Long-jun DONG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第8期2209-2219,共11页
In order to get the dynamic mechanical properties of deep rock mass suffered both high temperature and high pressure,impact loading experiments on granite subjected to temperature and axial pressure were carried out. ... In order to get the dynamic mechanical properties of deep rock mass suffered both high temperature and high pressure,impact loading experiments on granite subjected to temperature and axial pressure were carried out. Furthermore, the internalstructure characteristics of granite under different temperatures were observed by scanning electron microscopy (SEM). The results show that the longitudinal wave velocity assumes a downward trend which shows a rapid drop before falling slowly as the temperature increases. The uniaxial compressive strength of the specimen decreases significantly at temperatures of 25?100 °C compared to that at temperatures of 100?300 °C. The peak strain rises rapidly before the dividing point of 100 °C, but increases slowly after the dividing point. The internal structure of the rock changes substantially as the temperature increases, such as the extension and transfixion of primary and newborn cracks. In addition, the thermal damage under axial pressure is greater than that described by the longitudinal wave velocity and the phenomenon shows obviously when the temperature increases. 展开更多
关键词 rock dynamics split Hopkincon pressure bar temperature pressure coupling dynamic mechanical properties
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Temperature Dependency of Dynamic Mechanical Properties of Cement Asphalt Paste by DMTA Method 被引量:2
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作者 方雷 YUAN Qiang +3 位作者 PAN Yunrui WANG Yong KHAYAT Kamal 邓德华 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第6期1379-1387,共9页
We investigated the temperature dependency of the dynamic mechanical properties of cement asphalt paste by the dynamic mechanical thermal analysis(DMTA) method. The experimental results show that the dynamic mechani... We investigated the temperature dependency of the dynamic mechanical properties of cement asphalt paste by the dynamic mechanical thermal analysis(DMTA) method. The experimental results show that the dynamic mechanical properties of cement asphalt pastes are sensitive to temperature due to the inclusion of asphalt, and may go through different states within a temperature range of-40 ℃ to 60 ℃, which is different from that of pure cement and asphalt. As the temperature of the cement asphalt paste increases, a considerable change of dynamic mechanical properties, including storage modulus(E'), loss modulus(E'') and loss factor(tand) is observed. Moreover, the influence of asphalt to cement(A/C) ratio on the temperature sensitivity of the dynamic mechanical properties of cement asphalt composites was investigated. The temperature dependency of cement asphalt composites is ascribed to the temperature dependency of the asphalt and its interaction with cement paste. A simple fractional model is proposed to describe the viscoelastic behavior of cement asphalt composites. 展开更多
关键词 cement asphalt paste dynamic mechanical property dynamic mechanical thermal analysis viscoelastic model
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Morphology and Mechanical Properties of Nylon 6/PBT Blends Compatibilized with Styrene/Maleic Anhydride Copolymer 被引量:1
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作者 QIN Shu-hao YU Jie +2 位作者 ZHENG Qiang HE Min ZHU Hong 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2007年第6期726-732,共7页
The mechanical properties and dynamic mechanical properties of blends composed of Nylon 6 and poly ( butylenes terephthalate) (PBT), with styrene/maleic anhydride(SMA) as compatibilizer, were studied. The observ... The mechanical properties and dynamic mechanical properties of blends composed of Nylon 6 and poly ( butylenes terephthalate) (PBT), with styrene/maleic anhydride(SMA) as compatibilizer, were studied. The observation on the morphologies of the etched surfaces of the cryogenically fractured specimens via scanning electron microscopy(SEM) demonstrated that in the compatibilized Nylon 6/PBT blends, there exists a finer and more uniform dispersion induced by the in-situ interfacial chemical reactions during the preparation than that in the corresponding uncompatibilized blends. On the other hand, the overall mechanical properties of the compatibilized blends could be remarkably im- proved compared with those of the uncompatibilized ones. Moreover, increasing the amount of the compatibilizer SMA leads to a more efficient dispersion of the PBT phase in Nylon 6/PBT blends. Furthermore, there exists an optimum level of SMA added to achieve the maximum mechanical properties. As far as the mechanism of this reactive compatibilization is concerned, the enhanced interfacial adhesion is necessary to obtain improved dispersion, stable phase morphology, and better mechanical properties. 展开更多
关键词 NYLON-6 PBT MORPHOLOGY Dynamic mechanical property
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Microstructure Evolution and Dynamic Mechanical Properties of Laser Additive Manufacturing Ti-6Al-4V Under High Strain Rate 被引量:1
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作者 Tao Wang Lei Zhu +7 位作者 Changhong Wang Mingming Liu Ning Wang Lingchao Qin Hao Wang Jianbo Lei Jie Tang Jun Wu 《Journal of Beijing Institute of Technology》 EI CAS 2020年第4期568-580,共13页
The dynamic mechanical properties of the Ti-6Al-4V(TC4)alloy prepared by laser additive manufacturing(LAM-TC4)under the high strain rate(HSR)are proposed.The dynamic compression experiments of LAM-TC4 are conducted wi... The dynamic mechanical properties of the Ti-6Al-4V(TC4)alloy prepared by laser additive manufacturing(LAM-TC4)under the high strain rate(HSR)are proposed.The dynamic compression experiments of LAM-TC4 are conducted with the split Hopkinson pressure bar(SHPB)equipment.The results show that as the strain rate increases,the widths of the adiabatic shear band(ASB),the micro-hardness,the degree of grain refinement near the ASB,and the dislocation density of grains grow gradually.Moreover,the increase of dislocation density of grains is the root factor in enhancing the yield strength of LAM-TC4.Meanwhile,the heat produced from the distortion and dislocations of grains promotes the heat softening effect favorable for the recrystallization of grains,resulting in the grain refinement of ASB.Furthermore,the contrastive analysis between LAM-TC4 and TC4 prepared by forging(F-TC4)indicates that under the HSR,the yield strength of LAM-TC4 is higher than that of F-TC4. 展开更多
关键词 laser additive manufacturing TI-6AL-4V dynamic mechanics properties MICROSTRUCTURE
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Dynamic mechanical properties of PTFE-based composites filled with multi-component 被引量:1
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作者 王黎钦 李文忠 +1 位作者 古乐 郑德志 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2007年第6期799-802,共4页
To improve performance of PTFE-based damping material,composites with several fillers were prepared by compressing and sintering. The dynamic mechanical properties of the composites were investigated by means of visco... To improve performance of PTFE-based damping material,composites with several fillers were prepared by compressing and sintering. The dynamic mechanical properties of the composites were investigated by means of viscoanalyser. Temperature-dependent loss factors,storage modulus and loss modulus were obtained. And SEM was employed to study the compatibility between PTFE and fillers. The results show that,when blending PPS and PEEK at proper content,the loss factor curve appears double peaks,which can widen the high-damping temperature region of the composites. Blending graphite or alumina can increase the storage modulus obviously,but decrease the value of loss factor. And because graphite or alumina combines with matrix poorly,glide would happen at interface when bearing external load. The interface friction can dissipate vibration energy,which increases the loss modulus of the composites. Blending PPS,PEEK and graphite or alumina at right content,PTFE-based composites can meet demands as damping material in practical engineering. 展开更多
关键词 PTFE-based composite dynamic mechanical property PPS PEEK
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The study of measuring technology on the dynamic mechanical properties of welded joint with high strainrate 被引量:1
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作者 巩水利 张建勋 +1 位作者 裴怡 于琴 《China Welding》 EI CAS 2000年第1期30-37,共8页
In this paper, to meet the needs of studying work of dynamic mechanical properties of welded joint, the dynamic mechanical properties of welded joint were measured by means of SHPB(Split Hopkinson Pressure Bar).The dy... In this paper, to meet the needs of studying work of dynamic mechanical properties of welded joint, the dynamic mechanical properties of welded joint were measured by means of SHPB(Split Hopkinson Pressure Bar).The dynamic mechanical property's curves of every part of welded joint were obtained. For studying the dynamic behavior of mechanical heterogeneity of welded joint, important data were offered. The method of test creates a new way of studying dynamic mechanical properties of welded joint. 展开更多
关键词 welded joint dynamic mechanical properties measuring technology
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Mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions 被引量:3
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作者 熊良宵 虞利军 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期1096-1103,共8页
To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elas... To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution. 展开更多
关键词 cement mortar mechanical properties relative dynamic elastic modulus compressive strength
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Experimental study of the dynamic mechanical responses and failure characteristics of coal under true triaxial confinements 被引量:3
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作者 Zhanguo Ma Pengfei Yan +3 位作者 Shixing Cheng Peng Gong Fuzhou Qi Jianguo Wang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第6期761-772,共12页
Investigations on the dynamic mechanical properties and failure mechanisms of coal under in-situ stress is essential for the prevention of dynamic disasters in deep coal mines.Thus,a modified true triaxial Hopkinson b... Investigations on the dynamic mechanical properties and failure mechanisms of coal under in-situ stress is essential for the prevention of dynamic disasters in deep coal mines.Thus,a modified true triaxial Hopkinson bar was employed to explore the dynamic mechanical behaviors of coal at different confining pressures(0–20 MPa)and strain rates(40–220 s^(-1)).The results show that the dynamic peak stress is positively correlated with lateral static pre-stressσy andσz,but negatively correlated with axial static prestressσx.At approximate strain rates,increasing the lateral static pre-stress facilitates increasing the dynamic peak stress,but the minimum lateral static pre-stress is the primary factor limiting a significant increase in dynamic peak stress of coal.Furthermore,the dynamic differential stress is linearly related to the logarithm of strain rate,and the peak strain varies linearly with strain rate.However,there is no significant correlation between confining pressure and peak strain.Moreover,X-ray CT images and photographic fracture observations of coal samples show the failure patterns under uniaxial and triaxial conditions are splitting failure and shear failure,respectively.The device provides a viable approach for fully comprehending the dynamic mechanical behaviors of rock-like material in complex stress conditions. 展开更多
关键词 COAL True triaxial SHPB test Dynamic mechanical properties Failure characteristics
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Dynamic mechanical characteristics of frozen subgrade soil subjected to freeze-thaw cycles 被引量:2
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作者 WANG Dan LIU En-long +3 位作者 YANG Cheng-song LIU You-qian ZHU Sheng-xian YU Qi-hao 《Journal of Mountain Science》 SCIE CSCD 2023年第1期242-255,共14页
As a widely-applied engineering material in cold regions, the frozen subgrade soils are usually subjected to seismic loading, which are also dramatically influenced by the freeze-thaw(F-T)cycles due to the varying tem... As a widely-applied engineering material in cold regions, the frozen subgrade soils are usually subjected to seismic loading, which are also dramatically influenced by the freeze-thaw(F-T)cycles due to the varying temperature. A series of dynamic cyclic triaxial experiments were conducted through a cryogenic triaxial apparatus for exploring the influences of F-T cycles on the dynamic mechanical properties of frozen subgrade clay.According to the experimental results of frozen clay at the temperature of-10℃, the dynamic responses and microstructure variation at different times of F-T cycles(0, 1, 5, and 20 cycles) were explored in detail.It is experimentally demonstrated that the dynamic stress-strain curves and dynamic volumetric strain curves of frozen clay are significantly sparse after 20F-T cycles. Meanwhile, the cyclic number at failure(Nf) of the frozen specimen reduces by 89% after 20freeze-thaw cycles at a low ratio of the dynamic stress amplitude. In addition, with the increasing F-T cycles,the axial accumulative strain, residual deformation,and the value of damage variable of frozen clay increase, while the dynamic resilient modulus and dynamic strength decrease. Finally, the influence of the F-T cycles on the failure mechanisms of frozen clay was discussed in terms of the microstructure variation. These studies contribute to a better understanding of the fundamental changes in the dynamic mechanical of frozen soils exposed to F-T cycles in cold and seismic regions. 展开更多
关键词 Freeze-thaw cycles Frozen clay Dynamic triaxial test Dynamic mechanical properties
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EFFECTS OF MOLECULE AGGREGATION STATE OF HINDERED PHENOL ON DYNAMIC MECHANICAL PROPERTIES OF CHLORINATED POLYETHYLENE
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作者 吴驰飞 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2004年第1期7-16,共10页
Hindered phenol compound 3,9-bis{1,1-dimethyl-2[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}- 2,4,8,10-tetraoxaspiro[5,5]-undecane (AO-80) is a polymorphous material with different physical structures... Hindered phenol compound 3,9-bis{1,1-dimethyl-2[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}- 2,4,8,10-tetraoxaspiro[5,5]-undecane (AO-80) is a polymorphous material with different physical structures. The initial AO- 80 is highly crystalline, whereas AO-80 obtained by cooling from its molten state is an amorphous material. Annealing treatment below the melting point of AO-80 results in structural development. The mixture of chlorinated polyethylene (CPE) and vitrified AO-80 particles exhibits a dramatic change in the dynamic mechanical properties during heat treatment at 130'C. This change can be attributed to the decomposition of the vitrified AO-80 particles and the hybridization of two constituents. The vitrified AO-80 particles can crystallize again in a CPE matrix by annealing at 100'C, but this crystal is different from that of the initial AO-80 in its microstructure. In addition, the incorporation of CPE chains caused a dramatic increase in the modulus. As a result, the AO-80 crystal particles that contain some CPE chains act as multifunctional cross- links and the CPE/AO-80 hybrid was found to be a new type of elastomer. 展开更多
关键词 Hindered phenol Polymorphous Dynamic mechanical properties Chlorinated polyethylene
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Effects of thermal treatment on physical and mechanical characteristics of coal rock 被引量:15
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作者 YIN Tu-bing WANG Pin +2 位作者 LI Xi-bing SHU Rong-hua YE Zhou-yuan 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第9期2336-2345,共10页
To study the physical and mechanical properties of coal rock after treatment at different temperatures under impact loading, dynamic compression experiments were conducted by using a split Hopkinson pressure bar(SHPB)... To study the physical and mechanical properties of coal rock after treatment at different temperatures under impact loading, dynamic compression experiments were conducted by using a split Hopkinson pressure bar(SHPB). The stress–strain curves of specimens under impact loading were obtained, and then four indexes affected by temperature were analyzed in the experiment: the longitudinal wave velocity, elastic modulus, peak stress and peak strain. Among these indexes, the elastic modulus was utilized to express the specimens' damage characteristics. The results show that the stress–strain curves under impact loading lack the stage of micro-fissure closure and the slope of the elastic deformation stage is higher than that under static loading. Due to the dynamic loading effect, the peak stress increases while peak strain decreases. The dynamic mechanical properties of coal rock show obvious temperature effects. The longitudinal wave velocity, elastic modulus and peak stress all decrease to different extents with increasing temperature, while the peak strain increases continuously. During the whole heating process, the thermal damage value continues to increase linearly, which indicates that the internal structure of coal rock is gradually damaged by high temperature. 展开更多
关键词 rock mechanical property split Hopkinson pressure bar (SHPB) high temperature coal rock dynamic mechanical property
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Investigating the dynamic mechanical behaviors of polyurea through experimentation and modeling 被引量:17
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作者 Hao Wang Ximin Deng +3 位作者 Haijun Wu Aiguo Pi Jinzhu Li Fenglei Huang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2019年第6期875-884,共10页
Polyurea is widely employed as a protective coating in many fields because of its superior ability to improve the anti-blast and anti-impact capability of structures.In this study,the mechanical properties of polyurea... Polyurea is widely employed as a protective coating in many fields because of its superior ability to improve the anti-blast and anti-impact capability of structures.In this study,the mechanical properties of polyurea XS-350 were investigated via systematic experimentation over a wide range of strain rates(0.001-7000 s^-1)by using an MTS,Instron VHS,and split-Hopkinson bars.The stress-strain behavior of polyurea was obtained for various strain rates,and the effects of strain rate on the primary mechanical properties were analyzed.Additionally,a modified rate-dependent constitutive model is proposed based on the nine-parameter Mooney-Rivlin model.The results show that the stress-strain curves can be divided into three distinct regions:the linear-elastic stage,the highly elastic stage,and an approximate linear region terminating in fracture.The mechanical properties of the polyurea material were found to be highly dependent on the strain rate.Furthermore,a comparison between model predictions and the experimental stress-strain curves demonstrated that the proposed model can characterize the mechanical properties of polyurea over a wide range of strain rates. 展开更多
关键词 POLYUREA Strain rate effect Dynamic mechanical properties Constitutive model
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Effect of chemical modification on the properties of wood/polypropylene composites 被引量:14
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作者 QIN Te-fu HUANG Luo-hua LI Gai-yun 《Journal of Forestry Research》 SCIE CAS CSCD 2005年第3期241-244,共4页
Aluminate-based coupling agent was added as a compatibilizer to make the chemical modification of wood powder. The mechanical properties and morphology of wood powder/polypropylene composites were studied. The results... Aluminate-based coupling agent was added as a compatibilizer to make the chemical modification of wood powder. The mechanical properties and morphology of wood powder/polypropylene composites were studied. The results showed that the compatibilizer can increase the impact strength of the wood/polypropylene composites, but it has a slightly negative effect on the tensile and flexural strength. For dynamic mechanical properties and Differential Scanning Calorimetry, Aluminate-based coupling agent can slightly increase the storage modulus and loss modulus, and decrease the melt point and the Calorie of Melt. Scanning electron microscopy showed that Aluminate-based coupling agent had a stronger affinity between the wood and polypropylene surfaces. These results suggested that Aluminate-based coupling agent may play a useful role in improving wood powder/polypropylene composites properties. 展开更多
关键词 Powder/polypropylene composites mechanical properties Dynamic mechanical properties MORPHOLOGY
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Long-term mechanical behavior and characteristics of cemented tailings backfill through impact loading 被引量:9
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作者 Yu-ye Tan Elmo Davide +2 位作者 Yu-cheng Zhou Wei-dong Song Xiang Meng 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2020年第2期140-151,共12页
Cemented tailings backfill(CTB)structures are important components of underground mine stopes.It is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to di... Cemented tailings backfill(CTB)structures are important components of underground mine stopes.It is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to disturbance by dynamic loading,such as excavation and blasting.In this study,the authors present the results of a series of Split-Hopkinson pressure bar(SHPB)single and cyclic impact loading tests on CTB specimens to investigate the long-term dynamic mechanical properties of CTB.The stress-strain relationship,dynamic strength,and dynamic failure characteristics of CTB specimens are analyzed and discussed to provide valuable conclusions that will improve our knowledge of CTB long-term mechanical behavior and characteristics.For instance,the dynamic peak stress under cyclic impact loading is approximately twice that under single impact loading,and the CTB specimens are less prone to fracture when cyclically loaded.These findings and conclusions can provide a new set of references for the stability analysis of CTB materials and help guide mine designers in reducing the amount of binding agents and the associated mining cost. 展开更多
关键词 cyclic impact loading cemented tailings backfill dynamic mechanical properties Split–Hopkinson pressure bar dynamic peak stress
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DynamicMechanical and Chemorheology Analysis for the Blended Epoxy System with Polyurethane Modified Resin 被引量:2
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作者 Xue Xin Yu Rong +6 位作者 Linping Su Zhengmei Qiu Chenjun Yang Ming Liang Ping Ji Guoqiang Zhong Zhanyong Yao 《Journal of Renewable Materials》 SCIE EI 2022年第4期1081-1095,共15页
As the important matrix material,epoxy resin has been widely used in the composites for various fields.On account of the poor toughness of epoxy resin limiting their suitability for advanced applications,considerable ... As the important matrix material,epoxy resin has been widely used in the composites for various fields.On account of the poor toughness of epoxy resin limiting their suitability for advanced applications,considerable interests have been conducted to modify the epoxy resin to meet the engineering requirements.In this study,the bio-based polyurethane(PU)modified resin was adopted to modify the pure bisphenol-A epoxy by blending method with various proportions.Aiming to illuminate the curing behavior,mechanical and thermal properties,the blended epoxy systems were characterized by viscosity-time analysis,dynamic mechanical analysis(DMA)at different frequencies and temperatures,mechanical tensile test,thermogravimetric analysis(TGA)and Fourier transform infrared(FT-IR)spectroscopy.The results indicated that the introduction of PU modified epoxy was found to significantly inhibit the viscosity growth rates especially when the content of PU modified epoxy resin is higher than 60%.Notwithstanding the dynamic modulus and T_(g)reduced with the increment of PU modified epoxy,remarkable increment on the elongation at break was found and the flexibility was greatly promoted with the introduction of PU modified epoxy.The proportion of PU modified epoxy in the blends should be put balance considerations to obtain optimal mechanical properties.TGA results and FTIR spectrum demonstrated that the addition of PU modified epoxy did not change the thermal decomposition mechanism and chemical reaction mechanism,but the addition of PU modified epoxy inhibits the curing reaction of epoxy resin by measured and calculated the damping temperature domainT from 35.7℃ to 48.9℃. 展开更多
关键词 Dynamic mechanical property chemorheology analysis blended epoxy system polyurethane modified resin
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