The problem of quick analysis using exact geometry data was proposed by Hughes et al. and the isogeometric analysis framework was introduced as a solution. In this letter, the exact geometry concept is combined into the quasi-conforming framework and a novel method, i.e., the exact geometry based quasi-conforming analysis is proposed. In present method the geometry is exactly described by non-uniform rational B-spline bases, while the solution space by traditional polynomial bases. Present method combines the merits of both isogeometric analysis and quasi-conforming finite element method. In this letter Euler-Bernoulli beam problem is solved as an example and the results show that the present method is effective and promising.
基于Gurson-Tvergaard-Needleman（GTN）细观损伤模型,扩展其在平面应力、壳单元问题中的应力更新数值算法,研究高强度硼钢热冲压成形过程中板材内部的损伤演化行为。采用响应曲面中心复合试验设计和遗传优化算法,系统地阐述高温下GTN损伤参数的识别方法并获取了热成形高强度硼钢22Mn B5在高温下（600~800℃）的损伤特征参数（0,,,N Ff f f fc）。对耦合损伤的高强度钢板NAKJIMA凸模胀形热冲压过程进行有限元仿真预测,并与试验结果进行对比分析。结果表明：运用响应曲面法确定热冲压高温板材损伤参数的方法是可行的,同时采用GTN损伤模型可以准确模拟高强度钢板热冲压过程中的开裂行为。
The basic idea of quasi-conforming method is that the strain-dis-placement equations are weakened as well as the equilibrium equations.In this paper,an 18-DOF triangular element for couple stress theory is proposed within the framework of quasi-conforming technique.The formulation starts from truncated Taylor expansion of strains and appropriate interpolation functions are chosen to calculate strain integration.This element satisfies C0 continuity with second order accuracy and weak C1 continuity simultaneously.Numerical examples demonstrate that the proposed model can pass the C0??1 patch test and has high accuracy.The element does not exhibit extra zero energy modes and can capture the scale effects of microstructure.
