受火后6060-T6铝合金材料性能研究及本构模型标定

A study on the material properties of post-fire 6060-T6 aluminumalloy and calibration of the constitutive model

为评估铝合金结构受火后动态力学性能,应使用合理的受火后铝合金材料本构模型,采用万能试验机和分离式霍普金森压杆设备对结构用6060-T6铝合金开展系列受火后力学性能试验。首先,研究其力学性能指标随5个温度梯段的变化规律,发现材料在受火温度为450℃时弹性模量、屈服强度与抗拉强度最小;其次,选用经450℃受火冷却后6060-T6铝合金作为研究对象,当温度升高时,受火后铝合金表现出温度软化现象;然后,标定了能合理描述受火后铝合金塑性变形行为的Modified Johnson-Cook(MJC)本构模型;最后,采用一级轻气炮靶板冲击试验,得到受火后6060-T6铝合金弹道极限与失效模式,使用ABAQUS数值仿真软件建立相应靶板冲击模型,通过试验与仿真结果对比,验证了MJC本构模型参数的有效性。

In order to evaluate the dynamic mechanical properties of post-fire aluminum alloy structure,a reasonable constitutive model of post-fire aluminum alloy material should be used,a series of post-fire mechanical properties tests of 6060-T6 aluminum alloy were carried out using a universal testing machine and a Hopkinson pressure bar.Firstly,it was found that the elastic modulus,yield strength,and tensile strength of 6060-T6 aluminum alloy are the smallest when the fire temperature is 450℃.The 6060-T6 aluminum alloy cooled by 450℃fire was selected as the research object.When the temperature rises,the post-fire aluminum alloy shows the phenomenon of temperature softening.The Modified Johnson-Cook(MJC)constitutive model was calibrated,which can reasonably describe the plastic deformation behavior of post-fire aluminum alloy.Finally,the ballistic limit and failure mode of post-fire 6060-T6 aluminum alloy were obtained by the impact test of the first stage light gas gun target,the impact model of the target was established by ABAQUS,and the validity of the parameters of the MJC constitutive model was verified by the comparison of the experimental and numerical results.