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兵工学报 ›› 2024, Vol. 45 ›› Issue (12): 4339-4349.doi: 10.12382/bgxb.2023.1090

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冲击载荷作用下含损伤的低温混凝土本构模型研究

宁建国, 李玉辉, 杨帅, 许香照*()   

  1. 北京理工大学 爆炸科学与安全防护全国重点实验室, 北京 100081
  • 收稿日期:2023-11-07 上线日期:2024-03-05
  • 通讯作者:
    * 邮箱:
  • 基金资助:
    国家自然科学基金项目(12032006)

Research on Constitutive Model of Low-temperature Concrete Subjected to Impact Load

NING Jianguo, LI Yuhui, YANG Shuai, XU Xiangzhao*()   

  1. State Key Laboratory of Explosion Science and Safety Protection, Beijing Institute of Technology, Beijing 100081, China
  • Received:2023-11-07 Online:2024-03-05

摘要:

在严寒或寒冷地区服役环境下,混凝土力学性能与常温状态下有很大的差异。为了研究低温服役环境下混凝土的动态力学性能,开展混凝土的冲击加载试验;考虑温度和应变率的影响,基于热激活能的损伤理论,引入温度效应,对低温混凝土冲击损伤规律进行分析;通过混合律原理、二相材料的圆球模型和应变率效应的结合,将低温混凝土各组分模量联系起来,得到混凝土的等效模量;在Drucker-Prager屈服准则中引入损伤,建立由温度和应变率为参数的损伤演化函数,进而提出低温服役混凝土的动态本构模型。研究结果表明:随着服役温度的降低,混凝土碎块尺寸明显增大,破坏程度降低,这一现象表明冰对孔隙裂缝有一定的粘结作用,随着温度的降低,这种粘结效果会加强,从而抑制冲击加载过程中损伤的发展;随着服役温度的降低,孔隙中冰的含量及模量增加,混凝土强度显著增加。

关键词: 混凝土, 低温服役, 损伤, 含水率, 本构模型

Abstract:

The mechanical properties of concrete in a cold environment are different from those in normal temperature state. The impact loading test of concrete is made to study the dynamic mechanical properties of concrete under low temperature environment. In consideration of the influence of temperature and strain rate, the impact damage law of low-temperature concrete is analyzed by introducing the temperature effect based on damage theory of thermal activation energy. The moduli of all components of low-temperature concrete are associated with each other to obtain the equivalent modulus of concrete by using the principle of mixing law, the spherical model of two-phase material and the strain rate effect. Damage evolution function is introduced into Drucker-Prager yield criterion, which is established with temperature and strain rate as parameters, and a dynamic constitutive model of low temperature service concrete is proposed. The results show that the size of concrete fragments increases significantly and the damage situation decreases with the decrease in service temperature, which shows that the free water condenses into ice in concrete pore cracks at low temperature, and ice has a certain bonding effect on pore cracks. With the decrease in temperature, this bonding effect is strengthened, thus inhibiting the development of damage during impact loading. With the decrease in service temperature, the content and modulus of ice in pores increase, and the strength of concrete is significantly enhanced.

Key words: concrete, low temperature service, damage, moisture content, constitutive model

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