Glass fi ber reinforced gypsum(GFRG) wall panels are prefabricated panels with hollow cores, originally developed in Australia and subsequently adopted by India and China for use in buildings. This paper discusses ide...Glass fi ber reinforced gypsum(GFRG) wall panels are prefabricated panels with hollow cores, originally developed in Australia and subsequently adopted by India and China for use in buildings. This paper discusses identifi cation and calibration of a suitable hysteretic model for GFRG wall panels fi lled with reinforced concrete. As considerable pinching was observed in the experimental results, a suitable hysteretic model with pinched hysteretic rule is used to conduct a series of quasi-static as inelastic hysteretic response analyses of GFRG panels with two different widths. The calibration of the pinching model parameters was carried out to approximately match the simulated and experimental responses up to 80% of the peak load in the post peak region. Interestingly, the same values of various parameters(energy dissipation and pinching related parameters) were obtained for all fi ve test specimens.展开更多
Additional hysteretic experiments for corroded rectangular reinforced concrete(RC)columns with an axial load ratio of 0.27 were implemented.A quasi-static cyclic lateral loading with constant axial force was subjected...Additional hysteretic experiments for corroded rectangular reinforced concrete(RC)columns with an axial load ratio of 0.27 were implemented.A quasi-static cyclic lateral loading with constant axial force was subjected to tests.Herein,a modified ductility factor model for corroded RC column is developed on the basis of the previous work and additional experiments.The model involves the influence of both the corrosion ratio of longitudinal rebar and the axial load ratio.A four-linear envelope curve model concerning lateral load and displacement is proposed in a combination of determination rules of the peak point and the failure strength point.The hysteretic model of corroded RC columns is developed by considering both degraded unloading stiffness and reloading stiffness on the history peak point.The hysteretic model can predict the residual life of corroded RC columns under seismic loading.展开更多
The pipe-soil interactions at shoulders can significantly affect the vortex-induced vibrations (VIV) of free-spanning pipes in the subsea. In this paper, the seabed soil reacting force on the pipe is directly calculat...The pipe-soil interactions at shoulders can significantly affect the vortex-induced vibrations (VIV) of free-spanning pipes in the subsea. In this paper, the seabed soil reacting force on the pipe is directly calculated with a nonlinear hysteretic soil model. For the VIV in the middle span, a classic van der Pol wake oscillator is adopted. Based on the Euler-Bernoulli beam theory, the vibration equations of the pipe are obtained which are different in the middle span and at the two end shoulders. The static configuration of the pipe is firstly calculated and then the VIV is simulated.The present model is validated with the comparisons of VIV experiment, pipe-soil interaction experiment and the simulation results of VIV of free-spanning pipes in which the seabed soil is modelled with spring-dashpots. With the present model, the influence of seabed soil on the VIV of a free-spanning pipe is analyzed. The parametric studies show that when the seabed soil has a larger suction area, the pipe vibrates with smaller bending stresses and is safer.While with the increase of the shear strength of the seabed soil, the bending stresses increase and the pipe faces more danger.展开更多
This paper describes low cyclic loading testing of nine angle-steel concrete column （ASCC） specimens. In the tests, the influence of the shear-span ratio, axial compression ratio and shear steel plate ratio on the h...This paper describes low cyclic loading testing of nine angle-steel concrete column （ASCC） specimens. In the tests, the influence of the shear-span ratio, axial compression ratio and shear steel plate ratio on the hysteretic behavior, energy dissipation, strength degradation, stiffness degradation, skeleton curve and ductility of the ASCCs is studied. Based on the test results, some conclusions are presented. The P-A and sectional M -φ hysteretic models for the ASCCs are presented in a companion paper （Zheng and Ji, 2008）.展开更多
Tests of nine angle-steel concrete column （ASCC） specimens under low cyclic loading are described in a companion paper （Zheng and Ji, 2008）. In this paper, the skeleton curves from the numerical simulation are pre...Tests of nine angle-steel concrete column （ASCC） specimens under low cyclic loading are described in a companion paper （Zheng and Ji, 2008）. In this paper, the skeleton curves from the numerical simulation are presented, and show good agreement with the test results. Furthermore, parametric studies are conducted to explore the influence of factors such as the axial compression ratio, shear steel plate ratio, steel ratio, prismatic concrete compression strength, yield strength of angle steel and shear span ratio, etc., on the monotonic load-displacement curves of the ASCCs. Based on a statistical analysis of the calculated results, hysteretic models for load-displacement and moment-curvature are proposed, which agree well with the test results. Finally, some suggestions concerning the conformation of ASCCs are proposed, which could be useful in engineering practice.展开更多
As a preliminary step in the nonlinear design of shape memory alloy（SMA） composite structures,the force-displacement characteristics of the SMA layer are studied.The bilinear hysteretic model is adopted to describe ...As a preliminary step in the nonlinear design of shape memory alloy（SMA） composite structures,the force-displacement characteristics of the SMA layer are studied.The bilinear hysteretic model is adopted to describe the constitutive relationship of SMA material.Under the assumption that there is no point of SMA layer finishing martensitic phase transformation during the loading and unloading process,the generalized restoring force generated by SMA layer is deduced for the case that the simply supported beam vibrates in its first mode.The generalized force is expressed as piecewise-nonlinear hysteretic function of the beam transverse displacement.Furthermore the energy dissipated by SMA layer during one period is obtained by integration,then its dependencies are discussed on the vibration amplitude and the SMA＇s strain（Ms-Strain） value at the beginning of martensitic phase transformation.It is shown that SMA＇s energy dissipating capacity is proportional to the stiffness difference of bilinear model and nonlinearly dependent on Ms-Strain.The increasing rate of the dissipating capacity gradually reduces with the amplitude increasing.The condition corresponding to the maximum dissipating capacity is deduced for given value of the vibration amplitude.The obtained results are helpful for designing beams laminated with shape memory alloys.展开更多
In displacement-based seismic design, constant-ductility strength demand spectra （CDSDS） are very useful for preliminary design of new structures where the global displacement ductility capacity is known. The CDSDS ...In displacement-based seismic design, constant-ductility strength demand spectra （CDSDS） are very useful for preliminary design of new structures where the global displacement ductility capacity is known. The CDSDS can provide the required inelastic lateral strength of new structures from the required elastic lateral strength. Based on a statistical study of nonlinear time-history for an SDOF system, the mean CDSDS corresponding to four site conditions are presented and approximate expressions of the inelastic spectra are proposed, which are functions of the structural period and ductility level. The effects of site conditions, structural period, level of ductility, damping and post-yield stiffness of structures on CDSDS are also investigated. It is concluded that site conditions, ductility level and structural period have important effects on the CDSDS and damping, post-yield stiffness effects are rather complex and of minor importance. The damping, post-yield stiffness effects depend on both the level of ductility and the natural period of structures.展开更多
In this study,magnetomechanical coupling tests were performed on Q235 solid round steel model specimens in NIM-200HF magnetomechanical coupling equipment.Hysteresis loops were obtained in different magnetic fields and...In this study,magnetomechanical coupling tests were performed on Q235 solid round steel model specimens in NIM-200HF magnetomechanical coupling equipment.Hysteresis loops were obtained in different magnetic fields and stresses.Magnetization curves were also achieved at different stresses.Influence of the applied stresses on the hysteresis loops was investigated.The stress sensitive region and linear stress sensitive region of magnetic induction were determined for the model specimen according to the experimental data.The dependence relation of magnetic induction versus applied stresses was established,and the optimum magnetic field was determined in the stress sensitive range of magnetic induction,which builds a basis for nondestructive testing(NDT) of stress with the total magnetic flux for steel structure.Based on modified Jiles-Atherton's model of magnetic hysteresis,the hysteresis loop for Q235 steel 4-mm diameter model specimen was numerically simulated,which was well consistent with the experimental results.展开更多
文摘Glass fi ber reinforced gypsum(GFRG) wall panels are prefabricated panels with hollow cores, originally developed in Australia and subsequently adopted by India and China for use in buildings. This paper discusses identifi cation and calibration of a suitable hysteretic model for GFRG wall panels fi lled with reinforced concrete. As considerable pinching was observed in the experimental results, a suitable hysteretic model with pinched hysteretic rule is used to conduct a series of quasi-static as inelastic hysteretic response analyses of GFRG panels with two different widths. The calibration of the pinching model parameters was carried out to approximately match the simulated and experimental responses up to 80% of the peak load in the post peak region. Interestingly, the same values of various parameters(energy dissipation and pinching related parameters) were obtained for all fi ve test specimens.
基金the Programs for Changjiang Scholars and Innovative Research Team in University of the Ministry of Education of China(No.IRT1067)the National Natural Science Foundation of China(No.51868065)。
文摘Additional hysteretic experiments for corroded rectangular reinforced concrete(RC)columns with an axial load ratio of 0.27 were implemented.A quasi-static cyclic lateral loading with constant axial force was subjected to tests.Herein,a modified ductility factor model for corroded RC column is developed on the basis of the previous work and additional experiments.The model involves the influence of both the corrosion ratio of longitudinal rebar and the axial load ratio.A four-linear envelope curve model concerning lateral load and displacement is proposed in a combination of determination rules of the peak point and the failure strength point.The hysteretic model of corroded RC columns is developed by considering both degraded unloading stiffness and reloading stiffness on the history peak point.The hysteretic model can predict the residual life of corroded RC columns under seismic loading.
基金This study was financially supported by the National Natural Science Foundation of China(Grant No.51679167)the Natural Science Foundation of Shandong Province of China(Grant No.ZR2018MEE032)。
文摘The pipe-soil interactions at shoulders can significantly affect the vortex-induced vibrations (VIV) of free-spanning pipes in the subsea. In this paper, the seabed soil reacting force on the pipe is directly calculated with a nonlinear hysteretic soil model. For the VIV in the middle span, a classic van der Pol wake oscillator is adopted. Based on the Euler-Bernoulli beam theory, the vibration equations of the pipe are obtained which are different in the middle span and at the two end shoulders. The static configuration of the pipe is firstly calculated and then the VIV is simulated.The present model is validated with the comparisons of VIV experiment, pipe-soil interaction experiment and the simulation results of VIV of free-spanning pipes in which the seabed soil is modelled with spring-dashpots. With the present model, the influence of seabed soil on the VIV of a free-spanning pipe is analyzed. The parametric studies show that when the seabed soil has a larger suction area, the pipe vibrates with smaller bending stresses and is safer.While with the increase of the shear strength of the seabed soil, the bending stresses increase and the pipe faces more danger.
基金the New Century Excellent Talents in University Under Grant No.290Heilongjiang Key Program on Science and Technology Under Grant No.GC04A609Harbin Key Program on Science and Technology Under Grant No.2004AA9CS187
文摘This paper describes low cyclic loading testing of nine angle-steel concrete column （ASCC） specimens. In the tests, the influence of the shear-span ratio, axial compression ratio and shear steel plate ratio on the hysteretic behavior, energy dissipation, strength degradation, stiffness degradation, skeleton curve and ductility of the ASCCs is studied. Based on the test results, some conclusions are presented. The P-A and sectional M -φ hysteretic models for the ASCCs are presented in a companion paper （Zheng and Ji, 2008）.
基金the New Century Excellent Talents in University Under Grant No.290Heilongjiang Key Program on Science and Technology Under Grant No. GC04A609arbin Key Program on Science and Technology Under Grant No. 2004AA9CS187.
文摘Tests of nine angle-steel concrete column （ASCC） specimens under low cyclic loading are described in a companion paper （Zheng and Ji, 2008）. In this paper, the skeleton curves from the numerical simulation are presented, and show good agreement with the test results. Furthermore, parametric studies are conducted to explore the influence of factors such as the axial compression ratio, shear steel plate ratio, steel ratio, prismatic concrete compression strength, yield strength of angle steel and shear span ratio, etc., on the monotonic load-displacement curves of the ASCCs. Based on a statistical analysis of the calculated results, hysteretic models for load-displacement and moment-curvature are proposed, which agree well with the test results. Finally, some suggestions concerning the conformation of ASCCs are proposed, which could be useful in engineering practice.
基金supported by the National Natural Science Foundation of China (10872142 and 10632040)New Century Excellent Talents in University of China (NCET-05-0247)the Key Program of the Natural Science Foundation of Tianjin (09JCZDJ26800)
文摘As a preliminary step in the nonlinear design of shape memory alloy（SMA） composite structures,the force-displacement characteristics of the SMA layer are studied.The bilinear hysteretic model is adopted to describe the constitutive relationship of SMA material.Under the assumption that there is no point of SMA layer finishing martensitic phase transformation during the loading and unloading process,the generalized restoring force generated by SMA layer is deduced for the case that the simply supported beam vibrates in its first mode.The generalized force is expressed as piecewise-nonlinear hysteretic function of the beam transverse displacement.Furthermore the energy dissipated by SMA layer during one period is obtained by integration,then its dependencies are discussed on the vibration amplitude and the SMA＇s strain（Ms-Strain） value at the beginning of martensitic phase transformation.It is shown that SMA＇s energy dissipating capacity is proportional to the stiffness difference of bilinear model and nonlinearly dependent on Ms-Strain.The increasing rate of the dissipating capacity gradually reduces with the amplitude increasing.The condition corresponding to the maximum dissipating capacity is deduced for given value of the vibration amplitude.The obtained results are helpful for designing beams laminated with shape memory alloys.
基金Research Fund for the Doctoral Program of Higher Education (20030213042) and Heilongjiang Natural Science Foundation Under Grant No.ZJG03-03
文摘In displacement-based seismic design, constant-ductility strength demand spectra （CDSDS） are very useful for preliminary design of new structures where the global displacement ductility capacity is known. The CDSDS can provide the required inelastic lateral strength of new structures from the required elastic lateral strength. Based on a statistical study of nonlinear time-history for an SDOF system, the mean CDSDS corresponding to four site conditions are presented and approximate expressions of the inelastic spectra are proposed, which are functions of the structural period and ductility level. The effects of site conditions, structural period, level of ductility, damping and post-yield stiffness of structures on CDSDS are also investigated. It is concluded that site conditions, ductility level and structural period have important effects on the CDSDS and damping, post-yield stiffness effects are rather complex and of minor importance. The damping, post-yield stiffness effects depend on both the level of ductility and the natural period of structures.
基金the National Natural Science Foundation of China(Nos.51108035,51178388 and 10972168)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2010JQ7006)+1 种基金the China Postdoctoral Science Foundation(No.20100481313)the Special Fund for Basic Scientific Research of Central College of China(No.CHD2012ZD012)
文摘In this study,magnetomechanical coupling tests were performed on Q235 solid round steel model specimens in NIM-200HF magnetomechanical coupling equipment.Hysteresis loops were obtained in different magnetic fields and stresses.Magnetization curves were also achieved at different stresses.Influence of the applied stresses on the hysteresis loops was investigated.The stress sensitive region and linear stress sensitive region of magnetic induction were determined for the model specimen according to the experimental data.The dependence relation of magnetic induction versus applied stresses was established,and the optimum magnetic field was determined in the stress sensitive range of magnetic induction,which builds a basis for nondestructive testing(NDT) of stress with the total magnetic flux for steel structure.Based on modified Jiles-Atherton's model of magnetic hysteresis,the hysteresis loop for Q235 steel 4-mm diameter model specimen was numerically simulated,which was well consistent with the experimental results.
