混凝土材料动态拉伸强度的应变率强化规律

发布时间：2018-02-23 00:55

本文关键词： 混凝土应变率效应动态拉伸强度动态强化因子　出处：《高压物理学报》2017年05期 　论文类型：期刊论文

【摘要】：混凝土是重要的工程材料,研究其在动态作用下的力学性能具有极其重要的意义与价值。混凝土材料的动态拉伸强度具有明显的应变率效应,而且在低应变率与高应变率条件下的动态强化因子ψDIF(DIF:Dynamic Increase Factor)与应变率的关系具有明显的区别。参考现有的相关综述文献,收集近二十余年来大量的混凝土动态拉伸试验结果数据,结合理论分析,探讨了在不同应变率阶段混凝土材料拉伸强度动态强化因子的变化规律,以及不同试验手段如直接拉伸、动态劈裂与层裂等对拉伸动态强化因子的影响规律。最后对试验结果进行拟合,得到混凝土材料在不同应变率区间时拉伸强度动态强化因子的预测表达式。研究表明:(1)混凝土材料的动态强化因子ψDIF随着应变率的增加呈递增趋势,ψDIF-lnε·-具有类似的线性关系;(2)混凝土材料的拉伸强度ψDIF值随应变率增加而递增的趋势在3个不同应变率阶段,斜率明显不同,在高应变率时变化趋势最明显;(3)无论是低应变率区间还是高应变率区间,混凝土的动态拉伸强度ψDIF值与试验方式(直接拉伸、动态劈裂、层裂及其他方式)并没有明显的关系。
[Abstract]:Concrete is an important engineering material. It is of great significance and value to study its mechanical properties under dynamic action. The dynamic tensile strength of concrete material has obvious strain rate effect. Moreover, the relationship between the dynamic hardening factor 蠄 DIF(DIF:Dynamic Increase Increase and the strain rate under the condition of low strain rate and high strain rate is obviously different. Referring to the relevant literature, a large number of dynamic tensile test results of concrete have been collected in the past 20 years. Based on the theoretical analysis, the variation law of dynamic strengthening factors of concrete tensile strength at different strain rates and different test methods such as direct tension are discussed. The effect of dynamic splitting and spallation on tensile dynamic strengthening factor is studied. The prediction expression of dynamic strengthening factor of tensile strength of concrete material at different strain rate ranges is obtained. The study shows that the dynamic strengthening factor 蠄 DIF of concrete material increases with the increase of strain rate, and 蠄 DIF-ln 蔚-has a similar value. The tensile strength 蠄 DIF value of concrete material increases with the increase of strain rate in three different strain rate stages. The dynamic tensile strength (DIF) of concrete is different from that of the test method (direct tension, dynamic splitting, direct tension, dynamic splitting), whether in low strain rate range or high strain rate interval, the slope is obviously different, and the change trend is most obvious at high strain rate, no matter in low strain rate range or high strain rate interval, the dynamic tensile strength of concrete is different. Spallation and other means) have no obvious relationship.
【作者单位】：南京理工大学机械工程学院;
【基金】：国家自然科学基金(11472008,11202206) 教育部博士点专项基金(20123415120001) 中国博士后科学基金(2011M501057) 力学浙江省重中之重学科开放基金(XKLX1513) 中央高校基本科研业务费专项资金(30915118801)
【分类号】：TU528

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