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通过对KIEWITT-6型单层球面网壳缩尺模型进行模态测试及弹性与破坏性冲击试验,验证了基于ANSYS/LS-DYNA的网壳结构抗冲击荷载数值模型的正确性,确定了该模型的两种典型失效模式为结构局部凹陷与结构整体倒塌。综合试验与数值分析结果发现:冲击力时程曲线形式受冲击物初始偏转的影响;如果冲击结束时动力响应已经传到支座,将受到支座约束条件的影响;在弹性冲击范围内冲击力时程曲线形式对结构所受总冲量及结构动力响应的影响很小;破坏性冲击时冲击物初始偏转可能引起结构构件因非均匀受力而提前破坏,导致总冲量变小,从而引起失效模式改变较大,而不考虑初始偏转的分析结果偏于保守;虽然阻尼对冲击力的影响可以忽略,但后期对结构动力响应的影响较大,并可能改变失效模式;冲击力与动力响应对结构初始几何缺陷均不敏感。
Based on the modal test and the elastic and damaging impact test of KIEWITT-6 single-layer reticulated shell model, the numerical simulation of anti-impact load based on ANSYS / LS-DYNA is validated. Two typical failure modes of the model are local structural depression and structural collapse. The results of the comprehensive test and numerical analysis show that the form of the impact time history is affected by the initial deflection of the impactor. If the dynamic response has reached the bearing at the end of the impact, it will be affected by the restraint condition of the bearing. In the elastic impact range, The time-history curve has little effect on the total impulse and the structural dynamic response of the structure. The initial deflection of the impulse during destructive impact may lead to the premature failure of the structural member due to the non-uniform force, resulting in the decrease of the total impulse and the failure mode Although the influence of damping on impact is negligible, the effect on structural dynamic response is larger and the failure mode may be changed at later stage. The effect of impact and dynamic response on the structure Initial geometric defects are not sensitive.