地下拱形结构爆炸响应计算二维和三维模型比较

摘要

The buried arching structures'responses to explosion are always a hot tonic in protective engineering.In current practice,computing underground structures' responses to explosion mainly depends on empirical formulae by simplifying structure members' interaction but pertinent experimental data are extremely scarce.Finite element method is an available way to do it.However,a 3D modl needs an efficient computer and consumes much time,a 2D model is considered to replace the 3D model.It is important to compare performances of 2D and 3D models in order to find conditions for neglecting the differences between the computing results of 2D and 3D models.Here,the responses of underground arching structures subjected to explosion were simulated with 2D and 3D models using LSDYNA soft ware, respectively.The computation results with 2D and 3D models were compared.It was shown that the computing results with 2D and 3D models agree well just under the condition that the distance between the response point computed and the charge explosive position is beyond a certain value;the computing results of structural vibrations with 2D and 3D models agree better.%数值计算是研究地下拱形结构在爆炸荷载作用下动力响应问题的一种较好方法，数值计算过程中将三维（3D）模型简化为二维（2D）模型能提高数值计算效率，同时也会造成一定的计算误差。为了研究二维计算模型能否等效三维计算模型以及等效的前提条件和范围，采用数值计算分别对3D模型和2D模型爆炸冲击作用下地下拱形结构动力响应进行比较分析。计算结果表明：在两种计算模型中，自由场压力峰值的计算结果在装药周围差异较大，随着装药距离的增加趋于吻合；在2D模型中拱形结构的约束条件被增强，导致2D模型计算得到的应力、应变和质点振动速度偏小；当比例爆距大于一定值时2D模型和3D模型的计算结果吻合较好，计算表明该临界值为临界比例距离为2．76 m/kg1/3。