The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the fi...The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the filling content of nano-SiO2 particles on the mechanical properties of the dental composites was studied as well. The experimental results showed that the incorporation of the nano-SiO2 particles at low concentrations (up to 10 wt.%) can apparently increase the hardness and elastic modulus of the dental rein composites. The plasticity index indicates a best elastic recovery capability at a proper amount (4 wt.%) of the nanoparticles. Combined with the infrared spectrum, the mechanical enhancement mechanisms of the dental resin composites were analyzed.展开更多
Collagen fibers provide a good example of making strong micro-or mesoscale fibers from nanoscale tropocollagen molecules through a staggered and crosslinked organization in a bottom-up manner.Mimicking the architectur...Collagen fibers provide a good example of making strong micro-or mesoscale fibers from nanoscale tropocollagen molecules through a staggered and crosslinked organization in a bottom-up manner.Mimicking the architectural features of collagen fibers has been shown to be a promising approach to develop carbon nanotube(CNT)fibers of high performance.In the present work,an elastic model is developed to describe the load transfer and failure propagation within the bioinspired CNT bundles,and to establish the relations of the mechanical properties of the bundles with a number of geometrical and physical parameters such as the CNT aspect ratio and longitudinal gap,interface cross-link density,and the functionalizationinduced degradation in CNTs,etc.With the model,the stress distributions along the CNT-CNT interface as well as in every individual CNT are well captured,and the failure propagation along the interface and its effects on the mechanical properties of the CNT bundles are predicted.The work may provide useful guidelines for the design of novel CNT fibers in practice.展开更多
Tibiotalar arthrodesis(TTA)is a common surgical method for post-traumatic arthrosis and primary osteoarthrosis of ankle.Internal screw fixation exhibits such advantages of higher fusion rate and fewer complications th...Tibiotalar arthrodesis(TTA)is a common surgical method for post-traumatic arthrosis and primary osteoarthrosis of ankle.Internal screw fixation exhibits such advantages of higher fusion rate and fewer complications that it has become the mainstream surgical procedure in clinics.However,there are still disputes over the choice of screw type,number and nailing method.In this study,a 3D model of tibiotalar joint was established based on CT data.Two representative types of screws were modeled according to their real objects.Preprocessing was done in Hypermesh 2017,and the finite element simulations of different surgical schemes and postoperative ankle joint movements were performed via Abaqus 2016.The stress distribution in tibiotalar joints and screws,interarticular displacement,and screw deformation were extracted for comparative analyses.The results show that:(1)the three-screw fixation scheme with smaller displacements and higher contact pressure is superior to the two-screw one;(2)the relative displacements of the tibia and talus of full-thread screw under all loads were reduced by approximately 50%compared with those of lag screw,showing better stability;(3)the 60scheme is more favorable for joint fusion and more stable under vertical load,while the 75has the best bending resistance;(4)the stress and strain distributions in screws indicate that the screw break is most likely to happen near its contact region with the bone inlet,the maximum stress reaches 212.2 MPa.This study is of great significance for the selection and optimization of the surgical plan.展开更多
文摘The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the filling content of nano-SiO2 particles on the mechanical properties of the dental composites was studied as well. The experimental results showed that the incorporation of the nano-SiO2 particles at low concentrations (up to 10 wt.%) can apparently increase the hardness and elastic modulus of the dental rein composites. The plasticity index indicates a best elastic recovery capability at a proper amount (4 wt.%) of the nanoparticles. Combined with the infrared spectrum, the mechanical enhancement mechanisms of the dental resin composites were analyzed.
基金support from IHPC,A*STARpartially supported by the China Postdoctoral Science Foundation(Grant No.2014M562055)
文摘Collagen fibers provide a good example of making strong micro-or mesoscale fibers from nanoscale tropocollagen molecules through a staggered and crosslinked organization in a bottom-up manner.Mimicking the architectural features of collagen fibers has been shown to be a promising approach to develop carbon nanotube(CNT)fibers of high performance.In the present work,an elastic model is developed to describe the load transfer and failure propagation within the bioinspired CNT bundles,and to establish the relations of the mechanical properties of the bundles with a number of geometrical and physical parameters such as the CNT aspect ratio and longitudinal gap,interface cross-link density,and the functionalizationinduced degradation in CNTs,etc.With the model,the stress distributions along the CNT-CNT interface as well as in every individual CNT are well captured,and the failure propagation along the interface and its effects on the mechanical properties of the CNT bundles are predicted.The work may provide useful guidelines for the design of novel CNT fibers in practice.
基金The work was supported by National Natural Science Foundation of China[Grant Nos.11772240,11720101002,11542001,11502175]Jiangsu Natural Science Foundation[Grant No.BK20150381]+1 种基金the Fundamental Research Funds for the Central University,Translational Medicine and Interdisciplinary Research Joint Fund of Zhongnan Hospital of Wuhan University[Grant No.ZNJC201927]the Innovative Group Development Program at School of Civil Engineering,Wuhan University。
文摘Tibiotalar arthrodesis(TTA)is a common surgical method for post-traumatic arthrosis and primary osteoarthrosis of ankle.Internal screw fixation exhibits such advantages of higher fusion rate and fewer complications that it has become the mainstream surgical procedure in clinics.However,there are still disputes over the choice of screw type,number and nailing method.In this study,a 3D model of tibiotalar joint was established based on CT data.Two representative types of screws were modeled according to their real objects.Preprocessing was done in Hypermesh 2017,and the finite element simulations of different surgical schemes and postoperative ankle joint movements were performed via Abaqus 2016.The stress distribution in tibiotalar joints and screws,interarticular displacement,and screw deformation were extracted for comparative analyses.The results show that:(1)the three-screw fixation scheme with smaller displacements and higher contact pressure is superior to the two-screw one;(2)the relative displacements of the tibia and talus of full-thread screw under all loads were reduced by approximately 50%compared with those of lag screw,showing better stability;(3)the 60scheme is more favorable for joint fusion and more stable under vertical load,while the 75has the best bending resistance;(4)the stress and strain distributions in screws indicate that the screw break is most likely to happen near its contact region with the bone inlet,the maximum stress reaches 212.2 MPa.This study is of great significance for the selection and optimization of the surgical plan.
