纤维增强复合材料结构局部形状与环境腐蚀速率的关系研究

STUDY ON THE RELATIONSHIP BETWEEN LOCAL SHAPE AND ENVIRONMENTAL CORROSION RATE OF FIBER REINFORCED COMPOSITES

纤维增强复合材料(FRP)结构在外部环境作用下,不同位置的腐蚀速率并不一致,与该位置处FRP形状和环境作用有关。由于FRP结构形状多变的特点,常在梁柱交界处、FRP型材棱角处存在内凹角和外凸角,这些位置结构的腐蚀往往最为严重。本文对环境作用下FRP结构棱角处腐蚀速率的差异进行了理论分析和数值模拟。利用菲克定律下的扩散规律和有限元软件,计算了构件棱角不同角度与扩散速率的关系。定义并计算了棱角处于不同角度时的局部影响系数,结果表明,内部凹角对结构的腐蚀呈减弱影响,外部凸角对腐蚀呈放大效应。利用粒子抛射沉积与环境沉积的相似性,采用蒙特卡罗方法建立了不同粒子数目的粒子抛射沉积模型。定义并计算了角部的环境富集系数,分析发现凹角处会对环境产生汇集作用,凸角对环境分布影响相对较小。综合考虑了棱角对扩散速率的影响和环境富集的影响,定义并计算了结构形状影响系数,结果表明,结构物表面凸出和凹陷处更易受到环境腐蚀,结构耐久性设计时应考虑在棱角进行特殊防护设计。通过计算的结构形状影响系数可以为耐久性定量设计提供计算支持。

Under the external environment,the FRP structure has different corrosion rates at different locations,which is related to the FRP shape and the degree of environmental at the location.The shape of the FRP structure is variable,and there are often concave and convex angles at the intersection of the beam and column and at the corners of the FRP profile.The corrosion of these locations is often the most serious.In this paper,the theoretical analysis and numerical simulation of the difference of corrosion rate at the corners of FRP structure under environmental are carried out.Using the diffusion law under Fick’s law and finite element software,the relationship between the different angles of the component edges and the diffusion depth is calculated.The local diffusion coefficient of the corners at different angles is defined and calculated.The results show that the internal concave angle has a weakening effect on the corrosion of the structure,and the external lobes have a magnifying effect on the corrosion.Based on the similarity between particle deposition and environmental deposition,a Monte Carlo method was used to establish a particle deposition model with different particle numbers.The environmental enrichment coefficient of the corner is defined and calculated.It is found that the concave Angle has a pooling effect on the environment,while the convex Angle has a relatively small impact on the environmental distribution.Considering the influence of the angular angle on the diffusion rate and the influence of environmental enrichment,the structural shape influence coefficient is defined and calculated.The results show that the surface protrusions and depressions of the structure are more susceptible to environmental corrosion,and the structural durability design should consider special protection design at the corners.The calculated structural shape influence coefficient can provide computational support for the durability law design.