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建立了高孔隙率闭孔泡沫铝抗低速撞击的分析模型,通过落重冲击试验验证了模型预测的准确性;采用所建立的模型,计算了闭孔泡沫铝作为大质量结构抗低速冲击构件的临界冲击速度,研究了不同冲击条件下结构响应的最小加速度和临界加速度.结果表明,闭孔泡沫铝适合作为大质量结构的低速冲击防护材料:当撞击速度低于临界冲击速度时,泡沫铝的作用应力不会超过其平台压缩应力,具有高孔隙率的泡沫铝甚至可使冲击响应加速度大幅降低,具有优良的防护效果;当撞击速度超过相应条件下的临界速度时,由于泡沫铝压缩密实阶段的应力增强作用,不仅使其作用应力迅速增大(为平台应力的5-15倍),而且使冲击响应加速度迅速增加甚至超过1000g,从而对结构的安全防护构成威胁.最后,讨论了冲击质量比、泡沫铝孔隙率、泡沫几何尺寸等冲击参数对临界冲击速度和冲击响应加速度的影响.
The analytical model of high porosity closed-cell aluminum foam against low-velocity impact was established. The accuracy of model prediction was verified by falling-weight impact test. Using the established model, the closed-cell aluminum foam was calculated as a large-structure anti-low- Critical impact velocity and the minimum acceleration and critical acceleration of structural response under different impact conditions are studied.The results show that closed-cell aluminum foam is suitable as a low-speed impact protection material of large mass structure: When the impact velocity is lower than the critical impact velocity, the foam aluminum The effect of stress will not exceed the compressive stress of its platform, with high porosity of aluminum foam can even greatly reduce the impact response acceleration, with excellent protection effect; when the impact velocity exceeds the critical speed under the corresponding conditions, due to compact aluminum foam compression stage , Which not only increases the stress rapidly (5-15 times of the platform stress) but also increases the acceleration of shock response even more than 1000g, which poses a threat to the structural safety.Finally, the impact mass Ratio, foam aluminum porosity, foam geometry and other impact parameters on the critical impact velocity and impact Respond to the effects of acceleration.