泡沫混凝土弹塑性损伤模型在组合式防护结构中的应用

Application of plastic-damage material model for foam concrete in composite protective structure

为了将新型泡沫混凝土动态弹塑性损伤模型应用到防护结构中,首先开展组合式防护结构预制孔装药爆炸试验;随后利用新泡沫混凝土材料模型对试验进行数值模拟验证,并将新模型的模拟结果与LS-DYNA中Soil and Foam模型的模拟结果进行对比;最后,基于验证的数值模型,开展以梯度泡沫混凝土作为分配层的组合式防护结构预制孔装药爆炸的数值模拟,探讨梯度泡沫混凝土层界面层数和排列方式对组合式防护结构抗爆性能的影响。结果表明,新泡沫混凝土材料模型的模拟结果与试验结果吻合良好,与Soil and Foam模型相比,新模型在应力波传播和损伤破坏方面预测更好,泡沫混凝土层界面层数和排列方式对作用在主体结构上的应力以及分配层的损伤破坏情况有一定的影响。

An appropriate material model can accurately predict the mechanical behavior and damage mode of foam concrete subjected to blast loadings,and it has great significance on the design of composite protective structure.The purpose of this paper is to apply the new dynamic plastic-damage model for foam concrete presented by author to protective structures.Firstly,the new foam concrete model was briefly introduced.The model includes the definition of plasticity by introducing a yield function,flow rule and hardening law,the introduction of strain-rate effect and the definition of damage using plastic strain or related quantities.Subsequently,in order to validate the new model,the blast tests on the composite protective structure sandwiched by foam concrete with different strength were conducted and the stress waves at specific location and damage in foam concrete were recorded.Furthermore,the numerical results predicted by the new foam concrete model were compared to those predicted by the Soil and Foam model in the LS-DYNA.Finally,blast response of composite protective structure sandwiched by gradient foam concrete was numerically investigated based on the validated numerical model.The influences of arrangement and layers in gradient foam concrete layer on the anti-blast capability of composite protective structure were discussed by various working conditions.The results indicate that the numerical predictions excellently agreed with corresponding test data,demonstrating the accuracy of material model for foam concrete under blast loadings.Compared with the Soil and Foam model,the new model predicted better in terms of amplitude and duration of load on the structural layer,as well as the damage and failure in foam concrete layer.The gradient foam concrete numerical result showed that the arrangement and layers of foam concrete with different strength had an effect on the stress duration acting on the structure layer and the damage of the distribution layer.The new dynamic plastic-damage model for foam concrete has a broad application prospect in the research of protective structures.