Based on the harmonic vibration equation, the relationship between IR characteristic peak of fiberglass and Si-O-Si bond angle was deduced, and 1 100 cm^-1 characteristic peak was specifically studied. It is found tha...Based on the harmonic vibration equation, the relationship between IR characteristic peak of fiberglass and Si-O-Si bond angle was deduced, and 1 100 cm^-1 characteristic peak was specifically studied. It is found that 1 100 cm^-1 characteristic peak shifts to higher wave number when Si-O-Si bond angle increases. Taking fused biconical taper （FBT） coupler as an example, the microstructures of the fiber coupler manufactured at different draw- ing speeds were tested with micro infrared spectrum. According to the test results, it is found that the bond angle at the taper region is the largest, the one at the fused region is the second largest, and the one of bare fiber is the smal- lest. The characteristic peaks of fused-taper region shift to higher wave number when drawing speed increases.展开更多
Selection of materials,as an area of design research,has been under considerable interest over the years.Materials selection is one of the most important activities in the product development process.Inappropriate dec...Selection of materials,as an area of design research,has been under considerable interest over the years.Materials selection is one of the most important activities in the product development process.Inappropriate decision of materials can cause the product to be reproduced or remanufactured.To avoid this circumstance,one of the useful tools that can be employed in determining the most appropriate material is analytical hierarchy process(AHP).To illustrate the application of AHP,six different types of composite materials were considered.The most appropriate one for suitability of use in manufacturing automotive bumper beam was determined by considering eight main selection factors and 12 sub-factors.The AHP analysis reveals that the glass fibre epoxy is the most appropriate material because it has the highest value(25.7%,mass fraction) compared with other materials.The final material is obtained by performing six different scenarios of the sensitivity analysis.It is proved that glass fibre epoxy is the most optimum decision.展开更多
Given the increasing use of glass mat-reinforced thermoplastic(GMT)composites,the formability of GMT sheets is currently a topic of research.A new sheet forming process for solidified GMT was developed.In this process...Given the increasing use of glass mat-reinforced thermoplastic(GMT)composites,the formability of GMT sheets is currently a topic of research.A new sheet forming process for solidified GMT was developed.In this process,a GMT sheet was sandwiched by dummy metallic sheets during deep drawing.The dummy metallic sheets acted as protective materials and media for heating the GMT sheet.In this study,tensile tests of GMT specimens were carried out under different temperature conditions.The effect of temperature on the tensile deformation was analyzed.The effect of temperature on the deep drawing process of GMT sheets with dummy sheets was further investigated.Finite element method(FEM)was conducted to simulate the deep drawing process.In the drawing force rising stage,the law of drawing force with the depth of the drawing was analyzed using FEM and experiments.展开更多
The dissolution behavior of CaO-MgO-SiO2 glass fiber was investigated by scanning electron microscopy （SEM）, Fourier-transform infrared spectrometer （FTIR） and inductively coupled plasma atomic emission spectrosco...The dissolution behavior of CaO-MgO-SiO2 glass fiber was investigated by scanning electron microscopy （SEM）, Fourier-transform infrared spectrometer （FTIR） and inductively coupled plasma atomic emission spectroscopy （ICP-AES） using in-vitro tests. The results show that the soaked fiber is surrounded by an outer calcium-magnesium silicate hydrated layer, and there exists a balancing fimction between the formation and abscission of the hydrated layer during the dissolution process. The concentrations of leached ions increase constantly, and the mass loss of the fibers and pH changes of the solution are found to rise rapidly during the initial dissolution process, then their increasing rates are controlled by the balancing function of the hydrated layer at the subsequent dissolution stages. The dissolution rate constant and time for complete dissolution are estimated to be 274 ng/（cm2.h） and 15.2 d, respectively, presenting preferable biosolubilities.展开更多
The full-range behavior of partially bonded, together with partially prestressed concrete beams containing fiber reinforced polymer （FRP） tendons and stainless steel reinforcing bars was simulated using a simplified...The full-range behavior of partially bonded, together with partially prestressed concrete beams containing fiber reinforced polymer （FRP） tendons and stainless steel reinforcing bars was simulated using a simplified theoretical model. The model assumes that a section in the beam has a trilinear moment--curvature relationship characterized by three particular points, initial cracking of concrete, yielding of non-prestressed steel, and crushing of concrete or rupturing of prestressing tendons. Predictions from the model were compared with the limited available test data, and a reasonable agreement was obtained. A detailed parametric study of the behavior of the prestressed concrete beams with hybrid FRP and stainless steel reinforcements was conducted. It can be concluded that the deformability of the beam can be enhanced by increasing the ultimate compressive strain of concrete, unhonded length of tendon, percentage of compressive reinforcement and partial prestress ratio, and decreasing the effective prestress in tendons, and increasing in ultimate compressive strain of concrete is the most efficient one. The deformability of the beam is almost directly proportional to the concrete ultimate strain provided the failure mode is concrete crushing, even though the concrete ultimate strain has less influence on the load-carrying capacity.展开更多
Under the condition of equal flow, the maximum and minimum theoretical values of gap size were studied and an estimation equation was established for the clad extrusion of the brittle core cladded by plastic metal mat...Under the condition of equal flow, the maximum and minimum theoretical values of gap size were studied and an estimation equation was established for the clad extrusion of the brittle core cladded by plastic metal materials. The results show that the gap size is a key parameter for the continuous clad extrusion and the molding speed. Its maximum value (Hmax) is 0.24mm and the minimum one (Hmin) is 0.12mm. At a gap size of 0.18mm, the maximum of metal extrusion per unit of time and the optimal coating speed can be obtained.展开更多
A new "conceptual" design named "double pull" specimen was proposed in order to measure the bond-slip(δ-τ) relationship of fiber reinforced polymer(FRP)-to-concrete interface more accurately.A fi...A new "conceptual" design named "double pull" specimen was proposed in order to measure the bond-slip(δ-τ) relationship of fiber reinforced polymer(FRP)-to-concrete interface more accurately.A finite element analysis(FEA) was performed for preliminarily evaluating the suitability of the proposed conceptual double pull specimen.Through the FEA,it was indicated that the FRP-to-concrete interface of the proposed conceptual specimen might subject to a much higher load level than that of the most commonly used simple shear specimen,showing a great potential for measuring δ-τ relationship more accurately.In the light of the conceptual specimen,a kind of "practical" double pull specimen was developed and proved to be more suitable for measuring δ-τ relationship through an exploratory experimental study with 20 specimens.Consequently,an experimental program with 10 double pull specimens was performed for measuring the ultimate slip δu which was difficult to capture by using the existing specimens.It is shown that the range of δu is 0.31-0.52 mm based on the test results.The suggestion for improving the measure method is also put forward.展开更多
基金Project(50235040) supported bythe National Natural Science Foundation of China project(NCET-040753) supported bythe New Century Excellent Talents in University project(20050533037) supported by the research fund for the Doctoral Program ofHigher Education
文摘Based on the harmonic vibration equation, the relationship between IR characteristic peak of fiberglass and Si-O-Si bond angle was deduced, and 1 100 cm^-1 characteristic peak was specifically studied. It is found that 1 100 cm^-1 characteristic peak shifts to higher wave number when Si-O-Si bond angle increases. Taking fused biconical taper （FBT） coupler as an example, the microstructures of the fiber coupler manufactured at different draw- ing speeds were tested with micro infrared spectrum. According to the test results, it is found that the bond angle at the taper region is the largest, the one at the fused region is the second largest, and the one of bare fiber is the smal- lest. The characteristic peaks of fused-taper region shift to higher wave number when drawing speed increases.
基金the financial support through Research University Grant Scheme 2007 (RUG 2007) with vote number 91045
文摘Selection of materials,as an area of design research,has been under considerable interest over the years.Materials selection is one of the most important activities in the product development process.Inappropriate decision of materials can cause the product to be reproduced or remanufactured.To avoid this circumstance,one of the useful tools that can be employed in determining the most appropriate material is analytical hierarchy process(AHP).To illustrate the application of AHP,six different types of composite materials were considered.The most appropriate one for suitability of use in manufacturing automotive bumper beam was determined by considering eight main selection factors and 12 sub-factors.The AHP analysis reveals that the glass fibre epoxy is the most appropriate material because it has the highest value(25.7%,mass fraction) compared with other materials.The final material is obtained by performing six different scenarios of the sensitivity analysis.It is proved that glass fibre epoxy is the most optimum decision.
基金Project(CG2016003001)supported by the Ministry of Human Resources and Social Security of China
文摘Given the increasing use of glass mat-reinforced thermoplastic(GMT)composites,the formability of GMT sheets is currently a topic of research.A new sheet forming process for solidified GMT was developed.In this process,a GMT sheet was sandwiched by dummy metallic sheets during deep drawing.The dummy metallic sheets acted as protective materials and media for heating the GMT sheet.In this study,tensile tests of GMT specimens were carried out under different temperature conditions.The effect of temperature on the tensile deformation was analyzed.The effect of temperature on the deep drawing process of GMT sheets with dummy sheets was further investigated.Finite element method(FEM)was conducted to simulate the deep drawing process.In the drawing force rising stage,the law of drawing force with the depth of the drawing was analyzed using FEM and experiments.
基金Projects(50872098, 51004080) supported by the National Natural Science Foundation of ChinaProject(B0903) supported by the Opening Fund of Research Center of Green Manufacturing and Energy-saving & Emission Reduction Technology of Wuhan University of Science and Technology, China
文摘The dissolution behavior of CaO-MgO-SiO2 glass fiber was investigated by scanning electron microscopy （SEM）, Fourier-transform infrared spectrometer （FTIR） and inductively coupled plasma atomic emission spectroscopy （ICP-AES） using in-vitro tests. The results show that the soaked fiber is surrounded by an outer calcium-magnesium silicate hydrated layer, and there exists a balancing fimction between the formation and abscission of the hydrated layer during the dissolution process. The concentrations of leached ions increase constantly, and the mass loss of the fibers and pH changes of the solution are found to rise rapidly during the initial dissolution process, then their increasing rates are controlled by the balancing function of the hydrated layer at the subsequent dissolution stages. The dissolution rate constant and time for complete dissolution are estimated to be 274 ng/（cm2.h） and 15.2 d, respectively, presenting preferable biosolubilities.
基金Project (50478502) supported by the National Natural Science Foundation of China
文摘The full-range behavior of partially bonded, together with partially prestressed concrete beams containing fiber reinforced polymer （FRP） tendons and stainless steel reinforcing bars was simulated using a simplified theoretical model. The model assumes that a section in the beam has a trilinear moment--curvature relationship characterized by three particular points, initial cracking of concrete, yielding of non-prestressed steel, and crushing of concrete or rupturing of prestressing tendons. Predictions from the model were compared with the limited available test data, and a reasonable agreement was obtained. A detailed parametric study of the behavior of the prestressed concrete beams with hybrid FRP and stainless steel reinforcements was conducted. It can be concluded that the deformability of the beam can be enhanced by increasing the ultimate compressive strain of concrete, unhonded length of tendon, percentage of compressive reinforcement and partial prestress ratio, and decreasing the effective prestress in tendons, and increasing in ultimate compressive strain of concrete is the most efficient one. The deformability of the beam is almost directly proportional to the concrete ultimate strain provided the failure mode is concrete crushing, even though the concrete ultimate strain has less influence on the load-carrying capacity.
基金Project(2000 78) supported by the Key Science and Technology Project of Shandong Province
文摘Under the condition of equal flow, the maximum and minimum theoretical values of gap size were studied and an estimation equation was established for the clad extrusion of the brittle core cladded by plastic metal materials. The results show that the gap size is a key parameter for the continuous clad extrusion and the molding speed. Its maximum value (Hmax) is 0.24mm and the minimum one (Hmin) is 0.12mm. At a gap size of 0.18mm, the maximum of metal extrusion per unit of time and the optimal coating speed can be obtained.
基金Project(2006BAJ03A07) supported by the National Key Technologies R & D Program of ChinaProject(5008283) supported by the Natural Science Foundation of Guangdong Province, China
文摘A new "conceptual" design named "double pull" specimen was proposed in order to measure the bond-slip(δ-τ) relationship of fiber reinforced polymer(FRP)-to-concrete interface more accurately.A finite element analysis(FEA) was performed for preliminarily evaluating the suitability of the proposed conceptual double pull specimen.Through the FEA,it was indicated that the FRP-to-concrete interface of the proposed conceptual specimen might subject to a much higher load level than that of the most commonly used simple shear specimen,showing a great potential for measuring δ-τ relationship more accurately.In the light of the conceptual specimen,a kind of "practical" double pull specimen was developed and proved to be more suitable for measuring δ-τ relationship through an exploratory experimental study with 20 specimens.Consequently,an experimental program with 10 double pull specimens was performed for measuring the ultimate slip δu which was difficult to capture by using the existing specimens.It is shown that the range of δu is 0.31-0.52 mm based on the test results.The suggestion for improving the measure method is also put forward.
