The predictive capacity of numerical analyses in geotechnical engineering depends strongly on the efficiency of constitutive models used for modeling of interfaces behavior.Interfaces are considered as thin layers of ...The predictive capacity of numerical analyses in geotechnical engineering depends strongly on the efficiency of constitutive models used for modeling of interfaces behavior.Interfaces are considered as thin layers of the soil adjacent to structures boundary whose major role is transferring loads from structures to soil masses.An interface model within the bounding surface plasticity framework and the critical state soil mechanics is presented.To this aim,general formulation of the interface model according to the bounding surface plasticity theory is described first.Similar to granular soils,it has been shown that the mechanical behavior of sand-structure interfaces is highly affected by the interface state that is the combined influences of density and applied normal stress.Therefore,several ingredients of the model are directly related to the interface state.As a result of this feature,the model is enabled to distinguish interfaces in dense state from those in loose state and to provide realistic predictions over wide ranges of density and normal stress values.In evaluation of the model,a reasonable correspondence between the model predictions and the experimental data of various research teams is found.展开更多
基于次加载面的砂黏统一本构模型(clay and sand model with subloading surface,简称CASM-S)适用于描述砂土和超固结黏土的力学行为,然而该模型仍沿用线性临界状态描述砂土的应力−孔隙比关系。考虑高应力状态下砂土的压缩特性及其临界...基于次加载面的砂黏统一本构模型(clay and sand model with subloading surface,简称CASM-S)适用于描述砂土和超固结黏土的力学行为,然而该模型仍沿用线性临界状态描述砂土的应力−孔隙比关系。考虑高应力状态下砂土的压缩特性及其临界状态线在e-lnp平面内的非线性,在CASM-S中引入了描述砂土非线性临界状态线和参考固结线(reference compression curve,简称RCC)的幂函数形式;通过引入参数ξ和λ_(r),修正了CASM-S的屈服面与次加载面函数以描述砂土剪切特性,并利用参考固结线在e-(p/p_(a))^(ξ)(其中e为临界状态下的孔隙比,p为正应力,pa为标准大气压)平面内的线性关系给出了先期固结压力p_(c)0的求解方法。新建本构模型的11个参数均可通过常规土工试验或经验方法确定。基于修正CASM-S的预测结果,对比分析了4种砂土的三轴排水和不排水剪切试验结果,证实了该模型能够有效考虑非线性临界状态线的影响,并能够精确描述饱和砂土在不同孔隙比和围压下的三轴剪切特性。展开更多
In this study,we present the characterization of the carbon fibers recovered from the mechanochemical-enhanced recycling of carbon fiber reinforced fibers.The objectives of the study were to investigate the effect of ...In this study,we present the characterization of the carbon fibers recovered from the mechanochemical-enhanced recycling of carbon fiber reinforced fibers.The objectives of the study were to investigate the effect of our modified recycling method on the interfacial properties of recovered fibers.The reinforced plastics were recycled;the recycling efficiency was determined and the recovered fibers were sized using 1 wt%and 3 wt%concentration of(3-aminopropyl)triethoxysilane.We characterized the morphologies utilizing the electron spectroscopy for chemical analysis(ESCA),atomic force microscopy(AFM),FTIR-attenuated total reflection(ATR)spectroscopy and scanning electron microscopy(SEM).Although the surface of the fibers had no cracks,there was evidence of contaminations which affected the interfacial properties and the quality of the fibers.Results showed that the trends in the recovered and virgin fibers were similar with an increase in sizing concentration.The results highlighted the perspectives of increasing the quality of recovered fibers after the recycling process.展开更多
文摘The predictive capacity of numerical analyses in geotechnical engineering depends strongly on the efficiency of constitutive models used for modeling of interfaces behavior.Interfaces are considered as thin layers of the soil adjacent to structures boundary whose major role is transferring loads from structures to soil masses.An interface model within the bounding surface plasticity framework and the critical state soil mechanics is presented.To this aim,general formulation of the interface model according to the bounding surface plasticity theory is described first.Similar to granular soils,it has been shown that the mechanical behavior of sand-structure interfaces is highly affected by the interface state that is the combined influences of density and applied normal stress.Therefore,several ingredients of the model are directly related to the interface state.As a result of this feature,the model is enabled to distinguish interfaces in dense state from those in loose state and to provide realistic predictions over wide ranges of density and normal stress values.In evaluation of the model,a reasonable correspondence between the model predictions and the experimental data of various research teams is found.
文摘基于次加载面的砂黏统一本构模型(clay and sand model with subloading surface,简称CASM-S)适用于描述砂土和超固结黏土的力学行为,然而该模型仍沿用线性临界状态描述砂土的应力−孔隙比关系。考虑高应力状态下砂土的压缩特性及其临界状态线在e-lnp平面内的非线性,在CASM-S中引入了描述砂土非线性临界状态线和参考固结线(reference compression curve,简称RCC)的幂函数形式;通过引入参数ξ和λ_(r),修正了CASM-S的屈服面与次加载面函数以描述砂土剪切特性,并利用参考固结线在e-(p/p_(a))^(ξ)(其中e为临界状态下的孔隙比,p为正应力,pa为标准大气压)平面内的线性关系给出了先期固结压力p_(c)0的求解方法。新建本构模型的11个参数均可通过常规土工试验或经验方法确定。基于修正CASM-S的预测结果,对比分析了4种砂土的三轴排水和不排水剪切试验结果,证实了该模型能够有效考虑非线性临界状态线的影响,并能够精确描述饱和砂土在不同孔隙比和围压下的三轴剪切特性。
基金Project(S2598445)supported by the Project for Cooperative R&D between Industry,Academy and Research Institute Funded by the Korea Ministry of SME and Startups in 2018
文摘In this study,we present the characterization of the carbon fibers recovered from the mechanochemical-enhanced recycling of carbon fiber reinforced fibers.The objectives of the study were to investigate the effect of our modified recycling method on the interfacial properties of recovered fibers.The reinforced plastics were recycled;the recycling efficiency was determined and the recovered fibers were sized using 1 wt%and 3 wt%concentration of(3-aminopropyl)triethoxysilane.We characterized the morphologies utilizing the electron spectroscopy for chemical analysis(ESCA),atomic force microscopy(AFM),FTIR-attenuated total reflection(ATR)spectroscopy and scanning electron microscopy(SEM).Although the surface of the fibers had no cracks,there was evidence of contaminations which affected the interfacial properties and the quality of the fibers.Results showed that the trends in the recovered and virgin fibers were similar with an increase in sizing concentration.The results highlighted the perspectives of increasing the quality of recovered fibers after the recycling process.
