考虑界面影响的钢纤维混凝土等效力学性能研究

发布时间：2018-01-10 19:02

本文关键词：考虑界面影响的钢纤维混凝土等效力学性能研究　出处：《郑州大学》2013年硕士论文　论文类型：学位论文

【摘要】：混凝土作为主要的建筑工程材料已有上百年的历史,学者们对混凝土的力学性能也进行了深入的研究,取得了令人瞩目的成绩。工程中人们常将混凝土归类为宏观均匀各向同性材料,但是这种假设很难考虑到混凝土的细观组分和复杂性的力学性质,因此,对于这种多相复合材料需要从细观的角度来研究,推导出混凝土的宏观力学性能和微观结构之间的关系。在混凝土的内部结构上,由于化学和力学的原因,硬化的水泥砂浆体与各种粗骨料之间的界面上具有一定的粘结力,而且界面的粘结强度通常都低于硬化水泥砂浆体的抗拉压强度,因此界面是混凝土中最薄弱的地方,因而从细观的角度出发探讨细观结构下混凝土的破坏机理、物理力学性能等具有重大的意义。现如今,由于纤维增强复合材料的超强力学性能,钢纤维混凝土(SFRC)已广泛应用到各工程实际。钢纤维与混凝土基体之间的界面对钢纤维混凝土发挥其增强、增韧作用具有重大影响,故为了考证其微观结构特征,探讨SFRC微观结构与其宏观性能之间的关系,考虑了在无限平面内分布了任意数量的圆形钢纤维,采用超奇异积分方程和复变函数等数学方法对纤维、界面和基体三者之间边界上的应力、应变和位移等未知量建立数学模型。采用Galerkin积分方法和Gauss-Seidel迭代方法计算出在平面应变条件下该材料的等效弹性模量,并与宏观试验条件下已得出的混凝土弹性模量相比较,验证了该数学模型的精确度和适用性。
[Abstract]:As the concrete construction materials has been mainly on the hundred years of history, the mechanical properties of concrete scholars have conducted in-depth research, has made remarkable achievements in engineering. People often use concrete classified as macro isotropic materials, but this hypothesis is difficult to take into account the concrete meso mechanical properties group and the complexity of the result, the multiphase composite material from the meso perspective, the relationship between macro mechanical properties and microstructure of concrete is derived.
In the internal structure of concrete, due to chemical and mechanical, between hardened cement mortar and coarse aggregate interface has certain cohesive force, and the interfacial bond strength is usually lower than the hardened cement mortar tensile strength, so the interface is the weakest place of mixed concrete, and from microscopic view of the meso failure mechanism of concrete structure, is of great significance to the physical and mechanical properties.
Now, due to the strong mechanical properties of fiber reinforced composite material, steel fiber reinforced concrete (SFRC) has been widely applied to the engineering practice. Between steel fiber and concrete interface play of steel fiber reinforced concrete, has a significant impact on the toughening effect, in order to research the microstructure characteristic, explore the relationship between the microstructure of SFRC with the macro properties, considering the infinite plane distribution of circular steel fiber with arbitrary number of the hyper singular integral equation and complex function mathematical method of fiber stress boundary between the interface and the substrate three, the strain and displacement variables to establish the mathematical model. The calculated in equivalent elastic modulus the material under plane strain conditions by using Galerkin integral method and Gauss-Seidel iteration method, the elastic modulus of concrete and macroscopic experimental conditions have been derived in comparison to verify the The accuracy and applicability of the mathematical model.

【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528.572

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