Three-dimensional wound surface finite element expansion method for mapping skin material characteristics

Abstract

The invention discloses a three-dimensional wound surface finite element expansion method for mapping skin material characteristics, which relates to the field of reverse engineering and comprises four parts of topological relation reconstruction of a wound surface grid model, hierarchical division of a curved surface structure, equal deformation expansion of a wound surface and element material model optimization. According to the method, the reading and processing of wound surface data, the rapid topology reconstruction of the model, the hierarchical division of the wound surface structure, the morphological expansion of the wound surface model, the iterative optimization based on the unit material model and the multi-resolution fairing optimization of the flattened contour can be realized, and the method for determining the shape of the skin flap according to the wound surface shape is realized. The three-dimensional wound surface finite element expansion method has universality and effectiveness on disordered and irregular three-dimensional wound surfaces, the method is stable, the calculation process is simple, and clinical application results show that the preparation time of a preoperative scheme can be effectively shortened, the working efficiency of doctors can be improved, and the accuracy and evaluation reliability of the preoperative scheme can be improved.

Description

technical field [0001] The invention relates to the field of reverse engineering, in particular to a three-dimensional wound surface finite element expansion method for mapping skin material properties. Background technique [0002] Surface unwrapping is the process of mapping a spatial surface to a specific plane. In industrial design, engineers often determine the blank shape of the finished product through surface development, which is convenient for subsequent processing and manufacturing. According to the complexity of the shape, surfaces can be divided into simple surfaces and complex surfaces. Among them, most of the simple surfaces can be developed, that is, the Gaussian curvature on the surface is zero everywhere. During the expansion process, it can be transformed to a certain plane equidistantly, and the expansion results are accurate. and only. When a complex surface is mapped to a certain plane, deformation such as area and angle will inevitably occur. For exa...

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Problems solved by technology

In 1993, Parida proposed a geometric unfolding method for composite laminates. First, the surface is divided into multiple triangular meshes, and then the meshes are unfolded to the plane one by one. , but more cracks are generated during the unfolding process, and the cumulative error is more obvious

In 2015, in order to improve the design method of fiber composite materials, Kotaro divided the three-dimensional sheet model into two surfaces, and flattened it through the parametric method of the cross vector field. This method can handle thick plate materials in the fiber direction and thickness direction. large deformation, but whether it conforms to the real deformation of the actual material remains to be verified

[0004] For the study of mechanical methods, in 1991, Shinmada approximately transformed the space surface to a certain plane through dynamic programming. In the process, the surface to be developed was first divided into multiple strip regions based on the finite element method, and then each region was unfolded in turn. This method Not suitable for handling more complex surfaces

In 2001, Zhang Qilin deduced an incremental finite element method for surface expansion, transformed the expansion problem into the problem of finding a set of planar triangular elements whose size is closest to the space grid, and established the closest criterion, that is, triangular elements The residual nodal force is zero, but the efficiency of this method still needs to be improved when dealing with a large number of mesh nodes

[0005] For the current clinical preoperative flap design, the traditional sample tracing method is relatively rough and takes a long time to prepare. The process of formulating the plan is more dependent on the doctor's clinical experience and habits, and the matching degree of the cut flap and the wound is poor.

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