Abstract: Finite element method is adopted for many complex engineering structures. In order to estimate and control error, adaptive finite element method is applied very popularly in structure analysis. Based on a posteriori error estimate, the adaptive process is divided into two iterations, i.e. uniform iteration and gradation refinement iteration, and which is different from traditional schemes. In the uniform process, a constant mesh size is applied in the whole domain so that a proper initial uniform mesh can be achieved. In the gradation mesh iteration process, an element required refinement is triangulated locally within the curved triangle region to which it belongs. This step can make use of previous mesh to higher degree and get a satisfactory mesh size distribution so that different size triangles can be jointed smoothly. The whole scheme is simple and can be carried out easily. The iteration process can converged in several steps. The resultant mesh has a better size distribution and higher quality.

Key words: Adaptive finite element, Error estimation, Mesh refinement, Triangle