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为了表征改性双基推进剂的力学行为,推导出改性双基推进剂黏弹-黏塑性本构模型。利用一系列蠕变-回复试验,将材料的总应变分离为黏弹性应变和黏塑性应变,使用最小二乘法获得了黏弹性参数,使用Nelder-Mead单纯形优化算法,结合后向Euler数值方法获得了黏塑性参数。通过不同应力水平和不同加载时间的蠕变-回复试验对模型进行了验证,结果表明,在应力水平较低或加载时间较短的情况下,模型预测与试验值变化趋势基本一致,模型获得的黏弹性应变与黏塑性应变在总应变中所占的比例与试验吻合。改性双基推进剂黏弹-黏塑性本构模型能够在一定范围内描述材料的力学性能。
In order to characterize the mechanical behavior of modified double-base propellants, a viscoelastic-visco-plastic constitutive model of modified double-base propellants was derived. Using a series of creep-recovery tests, the total strain of the material was separated into viscoelastic strain and viscoplastic strain. The viscoelastic parameters were obtained by using the least square method. The Nelder-Mead simplex method and the backward Euler method The viscoplastic parameters. The model was verified by creep-recovery tests with different stress levels and different loading times. The results show that the trend of the model prediction and the test value are basically the same under the condition of low stress level or short loading time. The model obtained The ratio of viscoelastic strain to viscoplastic strain in total strain agrees well with the experiment. The viscoelastic-viscoplastic constitutive model of the modified double-base propellant can describe the mechanical properties of the material within a certain range.