摘 要 生产生活中，泡沫金属、人造烧结陶瓷、空心混凝土等多孔材料在隔热、隔音、冲击能量吸收、抑制振动、空气和水的过滤等方面都有着广泛的应用。孔隙率是影响多孔介质基本物理性质的重要显微结构参数，且力学性能又是评价材料以及选用的重要指标。因此，研究多孔介质力学性能的测试方法以及分析多孔介质孔隙率对于材料力学性能的影响是一个重要的研究课题。 基于弹性动力学相关的理论基础，超声纵波与横波在材料中的传播特性与材料的弹性模量和剪切模量密切相关。本文理论推导得到了单一模式的超声纵波和横波与相应力学性能参数之间的近似公式。文中通过一系列工艺制备不同孔隙率的氧化铝陶瓷材料，并采用动态法中的超声法作为测试多孔介质力学性能的方法。试验用 UVM-2 型声速测定仪与示波器搭建试验平台，采用脉冲循环法测定不同孔隙率氧化铝陶瓷的超声纵波及横波声速。接着分析氧化铝陶瓷的弹性模量和剪切模量等力学性能，并对样品的孔隙率对于力学性能的影响进行了研究。此外本文还用相同的方法对 Q235 钢以及铝合金试块的力学性能进行了测试，并将最后数据带入标准公式以及推导的近似公式计算得出结论。 58975
毕业论文关键词：多孔介质；孔隙率 ；超声波波速 ；弹性模量 ；剪切模量
Abstract In production and living, metal foam, sintered ceramic artificial, hollow concrete and other porous materials have a wide range of applications in heat insulation, sound insulation, impact energy absorption, suppress vibration, air and water filtration. Porosity is important microstructural parameters on affecting the basic physical properties of porous media and the mechanical properties is an important indicator to evaluate and choose materials. It is an important research topic to analyzing the testing method of mechanical properties of porous media and how the porous medium porosity affects the mechanical properties of materials. Based on the theoretical basis of the relevant elastic dynamics the propagation characteristics of ultrasonic longitudinal and shear waves in the materials have closely related to the elastic modulus and shear modulus. In this paper, the approximate formulas derived have been got by single mode ultrasonic longitudinal and transverse waves corresponding to the mechanical properties parameters. This article was prepared alumina ceramic materials with different porosity through a series of processes and using the ultrasonic method of dynamic method for testing the mechanical properties of the porous medium. The velocities of ultrasonic longitudinal and transverse wave in aluminum oxide ceramics were measured by UVM-2 sound analyzer. The elastic modulus and shear modulus of alumina ceramic were deduced by the velocities data. Then analyzing the mechanical properties of the elastic modulus and shear modulus of alumina ceramic and also studying the effect of porosity on mechanical properties. In addition, this article also used the same method to test the mechanical properties of Q235 steel and aluminum test block. Finally, the modulus calculated by standard formula and approximate formula were analyzed. The results show that with regard to the metal materials, the testing method by approximate formula can greatly simplify the procedure of measurement.
Keywords: porous media; porosity; ultrasonic velocity; elastic modulus; shear modulus
目录
第一章绪论1
1.1研究背景及意义1
1.2现有力学性能测试方法2
1.3超声法测试力学性能优势2
1.5本文主要研究内容5
第二章物理基础.6
2.1超声波理论基础6
2.1.1超声波分类.6 超声法研究多孔介质的力学性能:http://www.751com.cn/wuli/lunwen_64000.html