This paper presents a robust digital pipeline from CT images to the simulation of contact between multiple bodies. The proposed strategy relies on a recently developed immersed finite element algorithm that is capable of simulating unilateral contact between solids without meshing (Claus and Kerfriden in Int J Numer Methods Eng 113(6):938–966, 2018). It was shown that such an approach reduces the difficulties associated with the digital flow of information from analytically defined geometries to mechanical simulations. We now propose to extend our approach to include geometries, which are not defined mathematically but instead are obtained from images, and encoded in 3D arrays of voxels. This paper introduces two novel elements. Firstly, we reformulate our contact algorithm into an extension of an augmented Lagrangian CutFEM algorithm. Secondly, we develop an efficient algorithm to convert the surface data generated by standard segmentation tools used in medical imaging into level-set functions. These two elements give rise to a robust digital pipeline with minimum user intervention. We demonstrate the capabilities of our algorithm on a hip joint geometry with contact between the femur and the hip bone.

中文翻译：

---

使用切割有限元求解器对图像进行接触建模

本文提出了从 CT 图像到模拟多个身体之间接触的强大数字管道。所提出的策略依赖于最近开发的浸入式有限元算法，该算法能够在没有网格的情况下模拟固体之间的单边接触（Claus 和 Kerfriden 在 Int J Numer Methods Eng 113(6):938-966, 2018）。结果表明，这种方法减少了与从分析定义的几何形状到机械模拟的数字信息流相关的困难。我们现在提议将我们的方法扩展到包括几何，这些几何不是数学定义的，而是从图像中获得的，并在体素的 3D 阵列中编码。本文介绍了两个新颖的元素。首先，我们将我们的接触算法重新表述为增强拉格朗日 CutFEM 算法的扩展。第二，我们开发了一种有效的算法，将医学成像中使用的标准分割工具生成的表面数据转换为水平集函数。这两个元素以最少的用户干预产生了强大的数字管道。我们展示了我们的算法在股骨和髋骨之间接触的髋关节几何形状上的能力。