In the present study, the average modulus of delayed ettringite is evaluated by an experimental method combined with theoretical analysis. Firstly, the delayed ettringite crystal is synthesized by chemical reaction of...In the present study, the average modulus of delayed ettringite is evaluated by an experimental method combined with theoretical analysis. Firstly, the delayed ettringite crystal is synthesized by chemical reaction of Aluminum sulfate and calcium hydroxide. Secondly, specimens are obtained by compressing the delayed ettringite crystal under different pre-loads. Thirdly, the variation of the modulus of the specimen with different pre-loads is tested using Instron material test machine and the SHPB technique, respectively. It is found that the experimental data may be suitably fitted by Boltzmann Function. Finally, the porosity of the specimen is detected using the saturation method, and the effect of the porosity on the modulus is analyzed by the Eshelby＇s equivalent inclusion method and the Mori-Tanaka＇s scheme. The static and dynamic modulli of the equivalent homogeneous ettringite obtained in present study are approximately 10.64 GPa and 24.61 GPa, respectively.展开更多
An alternative strain energy method is proposed for the prediction of effective elastic properties of orthotropic materials in this paper. The method is implemented in the topology optimization procedure to design cel...An alternative strain energy method is proposed for the prediction of effective elastic properties of orthotropic materials in this paper. The method is implemented in the topology optimization procedure to design cellular solids. A comparative study is made between the strain energy method and the well-known homogenization method. Numerical results show that both methods agree well in the numerical prediction and sensitivity analysis of effective elastic tensor when homogeneous boundary conditions are properly specified. Two dimensional and three dimensional microstructures are optimized for maximum stiffness designs by combining the proposed method with the dual optimization algorithm of convex programming. Satisfactory results are obtained for a variety of design cases.展开更多
The global discussion surrounding Functionally Graded Materials(FGMs)highlights their unique and diverse micro-material properties that result from varying two or more materials in a strategic combination profile.Thes...The global discussion surrounding Functionally Graded Materials(FGMs)highlights their unique and diverse micro-material properties that result from varying two or more materials in a strategic combination profile.These combinations produce distinct physical and chemical characteristics.Changes in these characteristics may occur continuously,referred to as a gradient function,or discontinuously as a stepwise function.The changes can appear within homogeneous or heterogeneous material geometries.The variation in material properties depends on the volume fraction index function.This variation can occur in 1D,2D,or 3D,either in the thickness or length direction within a material model.The vacuum in the review study on mechanically toughened and thermally resistant Functionally Graded(FG)pipelines prompted the current review study.This study addresses the absence of an appropriate variational function for FG cylindrical pipelines.It proposes a gradation function pattern to improve pipeline structural performance.An appraisal based on relevant FGM literature was conducted to improve the temperature differentials in traditional composite materials and stress-related issues in carbon steel pipelines.The review identifies specific FGM property variations that reduce failures that are possible in conventional materials.Reviewed articles and evaluation procedures followed the 2020 PRISMA guidelines.Literature was obtained from Scopus,Connected Papers,and other reputable sources.The study also discusses potential FG pipelines for gas and green energy transportation.The reviewed literature establishes the context for this research and addresses the gap in 3D FG model variation functions involving multiple materials.展开更多
基金supported by the National Basic Research Program of China(973 Program,2009CB623203)the National Nature Science Foundation of China(Nos.10572064 and 10802039)+1 种基金Natural Science Foundation of Zhejiang Province (No.Y107780)K.C.Wong Magna Fund in Ningbo University.
文摘In the present study, the average modulus of delayed ettringite is evaluated by an experimental method combined with theoretical analysis. Firstly, the delayed ettringite crystal is synthesized by chemical reaction of Aluminum sulfate and calcium hydroxide. Secondly, specimens are obtained by compressing the delayed ettringite crystal under different pre-loads. Thirdly, the variation of the modulus of the specimen with different pre-loads is tested using Instron material test machine and the SHPB technique, respectively. It is found that the experimental data may be suitably fitted by Boltzmann Function. Finally, the porosity of the specimen is detected using the saturation method, and the effect of the porosity on the modulus is analyzed by the Eshelby＇s equivalent inclusion method and the Mori-Tanaka＇s scheme. The static and dynamic modulli of the equivalent homogeneous ettringite obtained in present study are approximately 10.64 GPa and 24.61 GPa, respectively.
基金The project supported by the National Natural Science Foundation of China(10372083,90405016)973 Program(2006CB601205)the Aeronautical Science Foundation(04B53080)
文摘An alternative strain energy method is proposed for the prediction of effective elastic properties of orthotropic materials in this paper. The method is implemented in the topology optimization procedure to design cellular solids. A comparative study is made between the strain energy method and the well-known homogenization method. Numerical results show that both methods agree well in the numerical prediction and sensitivity analysis of effective elastic tensor when homogeneous boundary conditions are properly specified. Two dimensional and three dimensional microstructures are optimized for maximum stiffness designs by combining the proposed method with the dual optimization algorithm of convex programming. Satisfactory results are obtained for a variety of design cases.
基金The Petroleum Training Development Fund(PTDF)is highly acknowledged for sponsorship.
文摘The global discussion surrounding Functionally Graded Materials(FGMs)highlights their unique and diverse micro-material properties that result from varying two or more materials in a strategic combination profile.These combinations produce distinct physical and chemical characteristics.Changes in these characteristics may occur continuously,referred to as a gradient function,or discontinuously as a stepwise function.The changes can appear within homogeneous or heterogeneous material geometries.The variation in material properties depends on the volume fraction index function.This variation can occur in 1D,2D,or 3D,either in the thickness or length direction within a material model.The vacuum in the review study on mechanically toughened and thermally resistant Functionally Graded(FG)pipelines prompted the current review study.This study addresses the absence of an appropriate variational function for FG cylindrical pipelines.It proposes a gradation function pattern to improve pipeline structural performance.An appraisal based on relevant FGM literature was conducted to improve the temperature differentials in traditional composite materials and stress-related issues in carbon steel pipelines.The review identifies specific FGM property variations that reduce failures that are possible in conventional materials.Reviewed articles and evaluation procedures followed the 2020 PRISMA guidelines.Literature was obtained from Scopus,Connected Papers,and other reputable sources.The study also discusses potential FG pipelines for gas and green energy transportation.The reviewed literature establishes the context for this research and addresses the gap in 3D FG model variation functions involving multiple materials.
