考虑边界条件的冲击回波检测套筒灌浆缺陷模拟方法研究

Research on the simulation method for detecting defects of sleeve grouting with impact echo considering boundary conditions

套筒灌浆连接作为一种预制混凝土结构连接方式正得到大规模应用,套筒内灌浆缺陷检测对保证结构性能至关重要,冲击回波法作为一种可行的无损检测方法具有广阔的应用前景。为研究三维数值模拟过程中,不同边界条件对模拟结果准确性和效率的影响,以数值模拟与理论计算得到的试件真实厚度频率作为参考,对比分析了无限元边界和自由边界下,不同尺寸无套筒缺陷试件模型,以及不同套筒内径的有缺陷试件模型的厚度频率分辨率特征。结果表明,在自由边界条件下,为了得到三维模型较准确的厚度频率,需要具有足够的模型尺寸,会带来计算量的剧增;无限元边界可降低反射杂波对厚度频率的准确率和分辨率的影响,较小的模型尺寸可取得良好的模拟效果。可为套筒灌浆缺陷检测方法的数值模拟提供参考。

Sleeve grouting connection,which is one kind of connection method of precast concrete structures,has been used widely,and the detection of grouting defects in the sleeve is very significant to ensure the structural performance.For the study of 3D numerical simulation in the process,different boundary conditions on the simulation accuracy and efficiency,the effect of numerical simulation and theoretical calculation of the specimen thickness of the real frequency for reference,comparison and analysis the infinite element boundary and free boundary,the different size without sleeve defects specimen model,and different sleeve diameter of flawed specimen thickness frequency resolution characteristic of the model.The results show that under the free boundary condition,in order to obtain the accurate thickness frequency of the 3D model,it is necessary to have enough model size,which will lead to a huge increase in computation.The infinite element boundary can reduce the influence of reflection clutter on the accuracy and resolution of the thickness frequency.It can provide reference for the numerical simulation of defect detection method of sleeve grouting.