基于能量法的混凝土双轴动态受压损伤特性研究
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摘要
为研究混凝土损伤特性,对边长为150 mm的立方体混凝土试块在不同侧向压力(0,0. 1f_c,0. 3f_c,0. 5f_c)和不同应变速率(10~(-5),10~(-4),10~(-3),10~(-2)s~(-1))下进行循环加卸载试验。用改进的Najar能量法确定了新的损伤变量表达式,以此分析侧向应力和应变速率对混凝土损伤演化的影响。研究结果表明:推荐的损伤变量表达式与混凝土实际受载情况相符;混凝土在双轴受压状态下损伤演化可以分为3个阶段:1)损伤不变阶段; 2)损伤加速发展阶段; 3)损伤发展完成阶段。侧应力对混凝土的损伤发展具有阻碍作用,侧应力越大,对裂缝发展的阻碍作用越强,混凝土的损伤发展滞后性越明显;应变速率对混凝土的损伤演化影响具有一定的规律性,侧应力一定时,混凝土的损伤随着应变速率的降低而滞后。
In order to study the damage characteristics of concrete,cyclic loading and unloading tests were carried out under different lateral pressures( 0,0. 1 f_c,0. 3 f_c,0. 5 f_c) and strain rates( 10~(-5),10~(-4),10~(-3),10~(-2) s~(-1)) for 150 mm cubic concrete blocks. A new damage variable expression was determined by the improved Najar energy method,and the effect of lateral stress and strain rate on damage evolution of concrete were analyzed. The results showed that the new expression of damage variable was consistent with the actual loading condition of concrete. The damage evolution of concrete under biaxial compression could be divided into three stages: 1) damage invariant stage; 2) accelerated damage development stage; 3) complete damage development stage. The lateral stress hindered the damage development of concrete. The larger the lateral stress,the stronger the hindrance to crack development,the more obvious the lag of damage development of concrete was. The effect of strain rate on damage evolution of concrete had certain regularity.When the lateral stress was constant,the damage of concrete lagged with the decrease of strain rate.
In order to study the damage characteristics of concrete,cyclic loading and unloading tests were carried out under different lateral pressures( 0,0. 1 f_c,0. 3 f_c,0. 5 f_c) and strain rates( 10~(-5),10~(-4),10~(-3),10~(-2) s~(-1)) for 150 mm cubic concrete blocks. A new damage variable expression was determined by the improved Najar energy method,and the effect of lateral stress and strain rate on damage evolution of concrete were analyzed. The results showed that the new expression of damage variable was consistent with the actual loading condition of concrete. The damage evolution of concrete under biaxial compression could be divided into three stages: 1) damage invariant stage; 2) accelerated damage development stage; 3) complete damage development stage. The lateral stress hindered the damage development of concrete. The larger the lateral stress,the stronger the hindrance to crack development,the more obvious the lag of damage development of concrete was. The effect of strain rate on damage evolution of concrete had certain regularity.When the lateral stress was constant,the damage of concrete lagged with the decrease of strain rate.
引文
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[11]宋玉普,王丽伟,王浩.大骨料混凝土率型内时损伤本构模型[J].大连理工大学学报,2015,55(1):47-53.
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[13]李杰,曾莎洁,任晓丹.混凝土动力随机损伤本构关系[J].同济大学学报(自然科学版),2014,42(12):1783-1789.
[14]李杰.混凝土随机损伤力学的初步研究[J].同济大学学报(自然科学版),2004,32(10):1270-1277.
[15]罗曦,彭刚,刘博文,等.用改进Najar能量法分析混凝土单轴受压损伤特性[J].水利水运工程学报,2016(5):103-108.
[16]丁发兴,余志武,欧进萍.混凝土单轴受力损伤本构模型[J].长安大学学报(自然科学版),2008,28(4):70-73.
[2] MAZARS J. A Description of Micro-and Macroscale Damage of Concrete Structures[J]. Engineering Fracture Mechanics,1986,25(5):729-737.
[3] ANANIEV S,OZBOLT J. Plastic-Damage Model for Concrete in Principal Directions[C]//Fracture Mechanics of Concrete Structures. Colorado,USA:2004:271-278.
[4] WU J Y,LI J,RUI F. An Energy Release Rate-Based PlasticDamage Model for Concrete[J]. International Journal of Solids&Structures,2006,43(3):583-612.
[5] ZHANG J,LI J. Investigation into Lubliner Yield Criterion of Concrete for 3D Simulation[J]. Engineering Structures,2012,44:122-127.
[6] RICHARD B,RAGUENEAU F. Continuum Damage Mechanics Based Model for Quasi Brittle Materials Subjected to Cyclic Loadings:Formulation, Numerical Implementation and Applications[J]. Engineering Fracture Mechanics,2013,98(1):383-406.
[7] OLIVER J,RUI F,CERVERA M. Modeling Material Failure in Concrete Structures Under Cyclic Actions[J]. Journal of Structural Engineering,2004,130(12):1997-2005.
[8]闫东明,刘康华,李贺东,等.带初始损伤混凝土的动态抗压性能研究[J].水利学报,2015,46(9):1110-1117.
[9]徐娜,傅学怡.基于能量损失理论的混凝土受压损伤本构模型[J].深圳大学学报(理工版),2017(6):604-610.
[10]龙渝川,侯鉴珊,王玉山.基于能量耗散的混凝土塑性-损伤模型[J].建筑结构学报,2017,38(9):147-153.
[11]宋玉普,王丽伟,王浩.大骨料混凝土率型内时损伤本构模型[J].大连理工大学学报,2015,55(1):47-53.
[12]杜荣强,林皋.混凝土弹塑性多轴损伤模型及其应用[J].大连理工大学学报,2007(4):567-572.
[13]李杰,曾莎洁,任晓丹.混凝土动力随机损伤本构关系[J].同济大学学报(自然科学版),2014,42(12):1783-1789.
[14]李杰.混凝土随机损伤力学的初步研究[J].同济大学学报(自然科学版),2004,32(10):1270-1277.
[15]罗曦,彭刚,刘博文,等.用改进Najar能量法分析混凝土单轴受压损伤特性[J].水利水运工程学报,2016(5):103-108.
[16]丁发兴,余志武,欧进萍.混凝土单轴受力损伤本构模型[J].长安大学学报(自然科学版),2008,28(4):70-73.