摘要
通过在大连理工大学海岸与近海工程国家重点实验室的大型静动态电液伺服试验系统上对普通混凝土受压试件在应变率为10-5/s～10-2/s范围内进行动态单轴直接抗压试验,分析了动态荷载下混凝土的抗压强度、弹性模量以及临界应变随应变率的变化规律,结果表明,混凝土的弹性模量随应变的增加而增加,混凝土的抗压强度和临界应变与应变率之间呈线性关系,并给出了抗压强度、临界应变受应变率影响的经验公式;以切线模量的退化来量度损伤,从损伤的角度分别在应力和应变空间分析了混凝土动态损伤槛值随应变率的变化规律和混凝土的动态损伤演化规律。研究表明,随着应变率的增大,混凝土损伤应力槛值增加,但损伤应力槛值与最大应力的比值变化不大,损伤应变槛值及其与临界应变的比值随着应变率的变化影响不大;在相同的应力比或应变比条件下,混凝土损伤值随着应变率的增加而减小。
Dynamic compression test of concrete specimens is carried out using a static-dynamic tfiaxial test system, with the axial strain rates ranging from 10^-5/s to 10^-2/s. The effects of strain rates on the compressive strength, elasticity modulus and critical strain of concrete are analyzed. Results show that the elasticity modulus of concrete increases with the strain rate, and the compressive strength and critical strain increase approximately linearly with the logarithm of strain rates. According to test results the experiential relationships between strain rates and the compressive strength, critical strain are established. Defining the damage of concrete with the reduction of the tangent modulus, the effects of strain rates on the damage threshold and evolution of concrete are analyzed in the stress and the strain spaces, respectively. It is found that the damage stress thresholds increase with the strain rate, while the ratios of the damage stress threshold to the ultimate strength are independent of strain rates. The damage strain thresholds and the ratios of the damage strain threshold to the critical strain are insensitive to the strain rates. The damage of concrete at the same stress or strain ratio decreases with the increase of strain rates.
出处
《土木工程学报》
EI
CSCD
北大核心
2010年第3期40-45,共6页
China Civil Engineering Journal
基金
国家自然科学基金(50408030)
辽宁省高等学校创新团队项目(2008T223)
关键词
混凝土
应变率
抗压强度
动态损伤
损伤槛值
concrete
strain rate
compressive strength
dynamic damage
damage threshold
