玻璃钢/复合材料 ›› 2017, Vol. 0 ›› Issue (1): 44-52.

• 基础研究 • 上一篇    下一篇

变截面纤维增强塑料梁结构的疲劳寿命分析方法

牛牧华1, 陈程2   

  1. 1.无锡太湖学院,无锡214064;
    2.南京航空航天大学航空宇航学院,南京210016
  • 收稿日期:2016-07-11 出版日期:2017-01-28 发布日期:2017-01-28
  • 作者简介:牛牧华(1986-),女,硕士,讲师,工程师,主要从事土木工程教学与研究,290696562@qq.com。
  • 基金资助:
    2015年度无锡太湖学院哲学社会科学和自然科学研究项目(*15WUNS003)

A FATIGUE ASSESSMENT METHOD FOR VARIABLE CROSS-SECTION FIBER REINFORCED PLASTIC BEAM

NIU Mu-hua1, CHEN Cheng2   

  1. 1.Tai Hu University of Wuxi, Wuxi 214064, China;
    2. College of Aerospace Engineering, NUAA, Nanjing 210016, China
  • Received:2016-07-11 Online:2017-01-28 Published:2017-01-28

摘要: 研究了一种变截面纤维增强塑料梁结构在风载、惯性作用等综合载荷作用下的疲劳寿命分析方法。MW级水平轴风机叶片是一种典型的变截面纤维增强塑料悬臂梁结构,其外载荷按照IEC61400的相关规定和GL(Germanisher Lloyd)规范,利用GH bladed软件对风力机的疲劳工况进行设定和载荷计算并获得疲劳载荷谱。为了解决沿展长和时间不断变化的载荷对求解带来的困难,通过有限元方法获得梁结构任意截面上各点的应力转换矩阵。应力转换矩阵可将无规律的疲劳载荷谱转换为各应力分量的应力谱,通过将应力谱利用雨流计数法进行统计,再根据材料的疲劳S-N曲线和Miner线性损伤叠加原理,即可得到梁结构上任意点的疲劳损伤和疲劳寿命。通过简单算例与商业软件FOCUS的计算结果对比,该方法能更方便地得到任意位置处、任意截面上的多轴向纤维增强塑料结构的疲劳性能,并且表明该有限元-应力转换矩阵方法对于评估变截面的纤维增强塑料梁结构在随机载荷作用下的疲劳性能是一种高效且可靠的方法。

关键词: 纤维增强塑料, 变截面梁, 风力机叶片, 疲劳, 应力转换矩阵

Abstract: A fatigue assessment method for variable cross-section fiber reinforced plastic beam under complex loads is studied. The blade of horizontal axis wind turbine is a typical reinforced plastic beam. Blade fatigue load cases are identified and loads are calculated by GH Bladed software, which is specified at the IEC61400 international specification and GL (Germanisher Lloyd) regulations. In order to resolve the problem resulting from the changing loads with time and beam span, stress analysis is performed with a finite element method (FEM). Considering Saint-Venant's principle, uniform cross section FEM model is built at each critical zone. Stress transformation matrixes (STM) are set up by applying six unit load components on FEM model separately. The total fatigue damage of each laminate on the critical point is counted by rain-flow counting method and Miner’s damage law based on general S-N curves. A comparison of the performance of this method is made with far more costly business software FOCUS. The results show that the fatigue damage of multi-axis FRP could be assessed conveniently by this FEM-STM method. And this proposed method gives a reliable and efficient method to analyze the fatigue damage of slender composite structure with variable cross-sections under irregular loading.

Key words: fiber reinforced plastic, variable cross-section beam, wind turbine blade, fatigue, stress transformation matrix

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