基于三角面元法的常磁性复杂形体磁异常正演

Magnetic Forward Modeling of Complex Body With Constant Magnetism Based on Triangular Surface Element Method

近源磁观测中,需要对场源形态和姿态进行精细的刻画,这对磁异常正演计算提出了新要求。针对这一问题,在常磁性条件下基于表面磁荷积分原理,探索了复杂形体高精度三角面元法磁异常正演模拟方法技术。针对工程磁探测中常见的复杂工程构件,借助有限元软件平台,绘制以三通管道、未爆弹为代表的复杂模型,并使用有限元计算模块的前期处理功能,对模型进行自动不规则三角网格剖分。编写平台间的数据接口软件,通过数据接口导出三角网格数据,并进行三角面元法磁异常正演。模型计算结果表明,近源观测时用简化模型代替复杂模型进行磁异常正反演可能会产生较大误差。

Aiming at near-source observation, under the condition of constant magnetism, a fast, accurate magnetic forward modeling method based on surface element integration theory is proposed to meet the new demand of precisely portraying sources′ shape and position in the magnetic forward modeling. To solve the high-precision forward modeling of complex model encountered in engineering magnetic survey, with the help of the finite element platform, common complex engineering components like Tee pipe and UXO(unexploded ordnance) were built. The pre-processing modulus of the finite element calculation give rise to the automatic building of irregular triangular mesh. Meanwhile, import and export channel is built to form a bi-directional channel between two platforms. The irregular triangular mesh data are used to calculate the magnetic anomaly of the complex engineering components. The model tests show that using simplified model to replace complex model can lead to great error in calculation of magnetic forward modeling and inversion.