低应变率下沙漠砂混凝土动态力学性能及本构模型

The dynamic constitutive model and mechanical behaviors of desert sand concrete at low strain rate

为研究沙漠砂混凝土动态力学性能,利用电液伺服万能试验机进行不同沙漠砂替代率下沙漠砂混凝土动态压缩试验;分析沙漠砂替代率和应变率对沙漠砂混凝土动态抗压强度和强度增强因子的影响,探讨低应变率下沙漠砂混凝土动态破坏模式;在非线性热黏弹性本构模型(ZWT模型)基础上,建立沙漠砂混凝土动态本构模型。研究表明:沙漠砂混凝土具有率相关性,随着应变率增大,沙漠砂混凝土动态抗压强度和强度增强因子逐渐增加;保持应变率不变,沙漠砂替代率为0%的沙漠砂混凝土强度增强因子最小;随着沙漠砂替代率增加,沙漠砂混凝土动态抗压强度呈现先增大后减小的趋势,沙漠砂替代率为40%时,沙漠砂混凝土动态抗压强度最大。

In order to research on the dynamic mechanical behaviors of desert sand concrete, the dynamic compressive tests of desert sand concrete with different desert sand substitution ratios were carried out by electro-hydraulic servo universal testing machines. The effects of desert sand substitution ratio and strain rate on the dynamic compressive strength and stress enhancement factor of desert sand concrete are analyzed. The failure mode of desert sand concrete at low strain rate is discussed. The dynamic constitutive model of desert sand concrete is established on the basis of nonlinear thermal viscoelastic constitutive model(ZWT model). The test results show that with the enhancement of strain rate, the dynamic compressive strength and stress enhancement factor of desert sand concrete increase, which shows that the desert sand concrete is rate-dependent. With the same strain rate, the stress enhancement factor of desert sand takes the minimum value when desert sand substitution ratio amounts to 0%. With increase of the desert sand substitution ratio, the dynamic compressive strength of desert sand concrete increases firstly, and then decreases. When desert sand substitution ratio reaches 40%, the dynamic compressive strength of desert sand concrete takes the maximum value.