Dynamic-Relaxation Method (DRM) is applied to studying the influence of compression-bending coupling on nonlinear behavior of cylindrically slightly curved panels of unsymmetric laminated composite materials subjected...Dynamic-Relaxation Method (DRM) is applied to studying the influence of compression-bending coupling on nonlinear behavior of cylindrically slightly curved panels of unsymmetric laminated composite materials subjected to uniform uniaxial Compression during loading and unloading. Numerical results are given for cross-ply plates and panels under S4S4 and S4S2 boundary conditions. The results show that the effects of absolute value and the sign of the coupling coefficient on the stability behavior of the panles are significant.展开更多
Creep test results of glulam members under compression and bending were studied in this paper.The creep tests were conducted to investigate the influence of the stress level and relative eccentricity on the creep defo...Creep test results of glulam members under compression and bending were studied in this paper.The creep tests were conducted to investigate the influence of the stress level and relative eccentricity on the creep deformation of glulam members.The test results showed that the creep deformation trends of glulam members under long-term compression and bending loading were similar;the creep deformation increased with increases in both the stress level and relative eccentricity.However,the relative creep deformation decreased with the increase in both the stress level and relative eccentricity under long-term loading,and a five-parameter creep model was proposed to analyse the creep mechanism of glulam members under compression and bending.The good fitness of the test results indicated that the five-parameter model was able to accurately simulate the creep deformation of glulam compression-bending members.Moreover,a numerical model was developed using the creep equation,which was related to the parameter a and b.The simulation results were in good agreement with the test results,and the parameters a and b were correlated to the relative eccentricity and stress level,respectively.Based on the corrected parameters a and b,the relative creep deformation of glulam compression-bending members was predicted over 50 years.展开更多
The mechanical properties of the steel-plate-reinforced segmental lining are generally determined by the load-bearing capacity of rein-forced joints.However,there is a lack of valid calculation methods for compression...The mechanical properties of the steel-plate-reinforced segmental lining are generally determined by the load-bearing capacity of rein-forced joints.However,there is a lack of valid calculation methods for compression-bending bearing capacity,and researchers mainly rely on experience and analogy for the design of reinforced joints.This paper proposes an analytical model based on the deformation and stress characteristics of the joint surface to calculate the compression-bending capacity of the steel-plate-reinforced joint.After verifying the applicability of this analytical model through finite element simulations,the evalution rules of the load-bearing capacity of the rein-forced joint were attained,followed by a quantitative investigation into the influence of joint parameters on it.The results show that:(1)the bearing capacity curve of the reinforced joint under different axial forces can be separated into two parts,with the maximum ultimate bending moment found at the demarcation point,where the steel plate yielding and joint failure occur simultaneously;(2)the steel plate strength and cross-sectional area have a strong infuence on the bearing capacity of the reinforced joint when the axial force is under 0.15RFF,where RFF is the axial force at pure-compression failure;(3)the concrete strength and segment width have a prominent influ-ence on the curve when the axial force is over 0.30RFF;(4)the impact of the fictitious strain,bolt strength,bolt diameter,and bolt loca-tion on the bearing capacity is minimal in range and amplitude.展开更多
In order to improve the load capacity, seismic performance and performance-cost ratio of the columns, the concrete at the base of reinforced concrete （RC） columns is substituted with engineered cementitious composit...In order to improve the load capacity, seismic performance and performance-cost ratio of the columns, the concrete at the base of reinforced concrete （RC） columns is substituted with engineered cementitious composites （ECC） to form ECC/RC composite columns. Based on the existing material properties, the mechanical behaviors of the ECC columns, ECC/RC composite columns and RC columns were numerically studied under combined vertical and horizontal loading with the software of ATENA. Then, the failure mechanism of ECC columns and ECC/RC composite columns were comprehensively studied and compared with that of the RC columns. Then, the effects of the height of the ECC, the axial compression ratio, and the transverse reinforcement ratio on the mechanical behaviors of the composite or the ECC column are studied. The calculation results show that the ultimate load capacity, ductility and crack resistance of the ECC or ECC/RC composite columns are superior to those of the RC columns. The ECC/RC composite column with a height of the ECC layer of 1.2h （ h is the height of the cross section） can achieve similar mechanical properties of a full ECC column. With high shear strength, ECC can undertake the shear force and significantly reduce the amount of stirrups, avoiding construction issues and promoting its engineering application.展开更多
文摘Dynamic-Relaxation Method (DRM) is applied to studying the influence of compression-bending coupling on nonlinear behavior of cylindrically slightly curved panels of unsymmetric laminated composite materials subjected to uniform uniaxial Compression during loading and unloading. Numerical results are given for cross-ply plates and panels under S4S4 and S4S2 boundary conditions. The results show that the effects of absolute value and the sign of the coupling coefficient on the stability behavior of the panles are significant.
基金The research described here was supported by the National Key Research and Development Program of China(Grant No.2017YFC0703506).
文摘Creep test results of glulam members under compression and bending were studied in this paper.The creep tests were conducted to investigate the influence of the stress level and relative eccentricity on the creep deformation of glulam members.The test results showed that the creep deformation trends of glulam members under long-term compression and bending loading were similar;the creep deformation increased with increases in both the stress level and relative eccentricity.However,the relative creep deformation decreased with the increase in both the stress level and relative eccentricity under long-term loading,and a five-parameter creep model was proposed to analyse the creep mechanism of glulam members under compression and bending.The good fitness of the test results indicated that the five-parameter model was able to accurately simulate the creep deformation of glulam compression-bending members.Moreover,a numerical model was developed using the creep equation,which was related to the parameter a and b.The simulation results were in good agreement with the test results,and the parameters a and b were correlated to the relative eccentricity and stress level,respectively.Based on the corrected parameters a and b,the relative creep deformation of glulam compression-bending members was predicted over 50 years.
基金support provided by the National Natural Science Foundation of China(Grant No.52278409).
文摘The mechanical properties of the steel-plate-reinforced segmental lining are generally determined by the load-bearing capacity of rein-forced joints.However,there is a lack of valid calculation methods for compression-bending bearing capacity,and researchers mainly rely on experience and analogy for the design of reinforced joints.This paper proposes an analytical model based on the deformation and stress characteristics of the joint surface to calculate the compression-bending capacity of the steel-plate-reinforced joint.After verifying the applicability of this analytical model through finite element simulations,the evalution rules of the load-bearing capacity of the rein-forced joint were attained,followed by a quantitative investigation into the influence of joint parameters on it.The results show that:(1)the bearing capacity curve of the reinforced joint under different axial forces can be separated into two parts,with the maximum ultimate bending moment found at the demarcation point,where the steel plate yielding and joint failure occur simultaneously;(2)the steel plate strength and cross-sectional area have a strong infuence on the bearing capacity of the reinforced joint when the axial force is under 0.15RFF,where RFF is the axial force at pure-compression failure;(3)the concrete strength and segment width have a prominent influ-ence on the curve when the axial force is over 0.30RFF;(4)the impact of the fictitious strain,bolt strength,bolt diameter,and bolt loca-tion on the bearing capacity is minimal in range and amplitude.
基金The National Natural Science Foundation of China(No.51278118)the Natural Science Foundation of Jiangsu Province(No.BK2012756)the Key Project of Ministry of Education of China(No.113029A)
文摘In order to improve the load capacity, seismic performance and performance-cost ratio of the columns, the concrete at the base of reinforced concrete （RC） columns is substituted with engineered cementitious composites （ECC） to form ECC/RC composite columns. Based on the existing material properties, the mechanical behaviors of the ECC columns, ECC/RC composite columns and RC columns were numerically studied under combined vertical and horizontal loading with the software of ATENA. Then, the failure mechanism of ECC columns and ECC/RC composite columns were comprehensively studied and compared with that of the RC columns. Then, the effects of the height of the ECC, the axial compression ratio, and the transverse reinforcement ratio on the mechanical behaviors of the composite or the ECC column are studied. The calculation results show that the ultimate load capacity, ductility and crack resistance of the ECC or ECC/RC composite columns are superior to those of the RC columns. The ECC/RC composite column with a height of the ECC layer of 1.2h （ h is the height of the cross section） can achieve similar mechanical properties of a full ECC column. With high shear strength, ECC can undertake the shear force and significantly reduce the amount of stirrups, avoiding construction issues and promoting its engineering application.
