杉木超声波无损检测试验研究

发布时间：2018-01-10 04:26

本文关键词：杉木超声波无损检测试验研究　出处：《南京工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：我国现存很多传统的木结构,其构件已处于超役阶段,部分木构件损伤严重,检测评估它们的剩余力学性能和内部缺陷是古建筑保护的第一步。无损检测技术既不破坏构件的内部结构,又不损伤其外部特征,近年来逐渐被应用于古建筑木结构检测中。目前,利用超声波无损检测技术评估木结构用板材、规格材性能的研究较多,但对于结构用原木评估的研究较少。在不破坏结构本身的前提下,如何能够于现场快速、有效地对原木构件的力学性能和内部缺陷进行无损评估,已经成为当前木结构工作者亟待解决的问题。本文选取南方古建筑木结构典型的树种——杉木原木作为研究对象,利用超声波对其进行了检测,主要的研究内容包括：1.首先根据超声波在固体介质中的传播知识,对沿原木纵向和径向的超声波传播理论进行研究,并对超声波检测木材力学性能和缺陷的基本原理进行了分析。2.采用Sylvatest-Duo超声波检测仪对杉木原木试件进行测试,对超声波在原木不同方向(径向与纵向)、不同测试位置(心材、边材)的传播速度进行分析,最后对沿原木纵向的超声波传播速度的轴向和径向变异规律进行研究。3.利用实验室方法对杉木试件的密度、顺纹抗压强度、抗拉强度、抗弯强度、顺纹抗压弹性模量进行测定,并将杉木纵向超声波传播参数与力学性能指标进行统计分析,得到杉木力学性能指标与超声动弹性模量的计算模型,探讨了在不破坏构件的前提下利用超声波对其力学性能进行评估的可行性。4.利用超声波对无任何缺陷和两种缺陷大小不同的木材试样进行检测,根据仪器所得参数,分析了超声波传播速度与不同类型缺陷大小的关系。5.为了更好地将超声波用于木结构现场检测,利用SPSS统计分析软件对超声波在原木中的传播参数进行了分析,结合数理统计的方法,给出了一种超声波在木材传播中的临界波速确定方法,为超声波现场勘察木材内部缺陷提供了依据。本文的研究成果为超声波在现场检测木结构构件的力学性能与内部缺陷的应用提供了理论和试验依据。
[Abstract]:There are many traditional wood structures in our country, and some of them are damaged seriously. Detection and evaluation of their residual mechanical properties and internal defects is the first step in the protection of ancient buildings. Non-destructive testing technology neither damage the internal structure of the members nor damage its external characteristics. In recent years, it has been gradually used in the wood structure testing of ancient buildings. At present, the ultrasonic nondestructive testing technology is used to evaluate the wood structure plate, and the performance of the specification material is studied more. However, there is little research on the evaluation of log structure. Without destroying the structure itself, how to evaluate the mechanical properties and internal defects of log members quickly and effectively in the field. It has become an urgent problem for wood structure workers at present. In this paper, Chinese fir log, a typical tree species of wood structure of ancient buildings in southern China, is selected as the research object, and ultrasonic wave is used to detect it. The main research contents include: 1. Firstly, according to the knowledge of ultrasonic propagation in solid media, the theory of ultrasonic propagation along log longitudinal and radial is studied. The basic principle of ultrasonic detection of wood mechanical properties and defects was analyzed. 2. The Chinese fir log samples were tested by Sylvatest-Duo ultrasonic detector. The propagation velocity of ultrasonic wave in different direction of log (radial and longitudinal) and different testing position (heartwood, sapwood) was analyzed. Finally, the axial and radial variation of ultrasonic propagation velocity along log longitudinal was studied. 3. The density, compression strength, tensile strength and bending strength of Chinese fir specimens were studied by laboratory method. The longitudinal ultrasonic propagation parameters and mechanical properties of Chinese fir were statistically analyzed, and the calculation model of mechanical properties and dynamic elastic modulus of Chinese fir was obtained. The feasibility of using ultrasonic wave to evaluate the mechanical properties of the components without destroying the components is discussed. 4. Ultrasonic testing of wood samples without any defects and different sizes of two defects is carried out. According to the parameters obtained from the instrument, the relationship between ultrasonic propagation speed and the size of different types of defects is analyzed. 5. In order to better use ultrasonic wave in the field detection of wood structure. The propagation parameters of ultrasonic wave in log were analyzed by using SPSS software, and a method of determining the critical wave velocity of ultrasonic wave in wood propagation was given in combination with the method of mathematical statistics. The research results of this paper provide theoretical and experimental basis for the application of ultrasonic wave in the field inspection of the mechanical properties and internal defects of wood structural components.
【学位授予单位】：南京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU317;TU366.2

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