古建筑木构件内部缺陷无损筛查方法研究
发布时间：2018-11-17 07:00
【摘要】：随着科技的发展和实际的需要,无损检测技术已逐步从机械工程等一般工业领域引入并应用到木质材料领域中来。木构件的缺陷是影响木结构古建筑安全性能的重要因素之一,在长期使用过程中由于木材本身特性,木构件会因为有害生物侵蚀、含水率变化等因素而出现腐朽、孔洞、裂纹等缺陷,从而严重影响木构件的使用性。在古建筑木结构例行检测、评估过程中,需要首先对各木构件内部缺陷情况进行快速筛查,即利用无损检测技术对木构件内部状况进行系统的排查,对内部缺陷的有无和大小进行初步判定和估算,为下一步内部缺陷尺寸的精确检测与木结构安全性计算打下基础。目前常用的古建筑木构件内部缺陷无损筛查方法主要包括用于初步筛查的敲击法,用于验证性筛查的应力波法和微钻阻力法等；存在的不足是准确度差、检测效率低。为了更好地满足古建筑木构件内部缺陷筛查的要求并结合实际检测工作中遇到的问题,本文对应力波法、微钻阻力法、敲击法等古建筑木构件内部缺陷无损筛查方法进行了进一步深入研究,解决了应力波法和微钻阻力法检测筛查过程中的一些关键问题；深入探索了敲击法的机理,便捷了敲击法的使用。论文主要研究内容和创新如下。首先,针对目前国内外广泛用于古建筑木构件内部缺陷验证性筛查的应力波法和微钻阻力法在实际运用中的问题,提出了古建筑木构件应力波临界速度和一套结合这两种检测技术快速、有效筛查木构件内部缺陷的检测方法。利用Fakopp应力波检测仪对古建筑木构件常用的兴安落叶松(Larix gmelinii)、杉木(Cunninghamia Lanceolata)、琼楠(Beilschmiedia)进行了应力波波速的检测和统计,再结合统计学原理确定了三种树种的应力波临界速度,在一定程度上提高了应力波法筛查古建筑木构件内部缺陷的效率和准确度。同时将应力波检测和微钻阻力检测进行了合理的联合,先通过应力波检测确定木构件内部缺陷的有无、大致位置,再利用微钻阻力检测进一步判断缺陷的类型和尺寸。该方法能够在损伤尽可能少的情况下对古建筑木构件内部缺陷进行快速、有效的验证性筛查。其次,针对敲击法准确度低、过度依靠检测人员经验的不足,以提高其科学性和准确度为目标,研究了利用敲击声音筛查木构件内部缺陷方法的检测机理。通过试验发现敲击木构件可能引起不同的振动,并将敲击有内部孔洞缺陷的木构件的振动分为表面局部振动、整体振动和缺陷部位振动三种振动形式。通过机械振动模型简化分别研究了三种振动的频率、振幅等参数,以及不同缺陷情况下振动参数的变化及规律；并且分析了将三种振动有效结合后来模拟实际敲击有内部空洞缺陷木构件的各种情况作为木构件内部缺陷的陷筛依据。在前面敲击检测机理研究基础上,分别对落叶松材的长方体和圆柱体两种木构件试件分别进行了敲击检测试验。通过后期加工出不同的孔洞来模拟木构件的内部缺陷,采集敲击声音信号并利用信号分析研究木构件内部缺陷对敲击声音的影响。通过统计分析发现,声音信号中均方根值、频率等特征参数会随着内部缺陷的改变而发生相应的变化且具有一定的规律。并且,敲击试验中声音信号特征参数的变化规律与各简化模型中的振动参数的变化规律在一定范围内是一致的,在一定程度上证实了敲击检测机理研究的正确性,从而可以通过这些特征筛查出内部缺陷。综合敲击筛查木构件内部缺陷试验结果,利用模糊模式识别法处理敲击试验数据。经过对试验数据样本的规格化、模糊等价矩阵的建立及聚类计算分析,实现了木构件内部缺陷快速敲击筛查的信号处理便捷化,降低了敲击筛查木构件内部缺陷方法对检测人员经验的依靠,同时提高了该方法的准确度、科学性及实用性。最后,将研究成果应用于北京市木结构古建筑的实际检测工作当中,取得了较好的效果。
[Abstract]:With the development of science and technology and the actual need, the non-destructive testing technology has been gradually introduced and applied to the field of wood materials from the general industrial fields such as mechanical engineering. The defect of the wood component is one of the important factors that affect the safety performance of the wood structure ancient building. In the long-term use process, due to the characteristics of the wood, the wood component can be decayed, the hole, the crack and other defects due to the factors such as the harmful effect of the harmful organisms and the change of the water content. thereby seriously affecting the usability of the wood member. in that proces of routine detection and evaluation of the wood structure of the ancient building, the internal defect condition of each wood component needs to be quickly screened, namely, the internal condition of the wood component is checked by the non-destructive detection technology, and the presence or absence and the size of the internal defect are preliminarily determined and estimated, and lays a foundation for the accurate detection of the internal defect size and the calculation of the structural safety of the wood structure for the next step. The method for non-destructive screening of the internal defects of the conventional ancient building wood component mainly comprises a knocking method for preliminary screening, a stress wave method for verifying sexual screening and a micro-drilling resistance method, and the like, and the defect is that the accuracy is poor and the detection efficiency is low. In order to better meet the requirement of the internal defect screening of the ancient building and the problems encountered in the practical test, this paper makes a further study on the method of non-destructive screening of the internal defects of the ancient building, such as the stress wave method, the micro-drilling resistance method and the knocking method. The key problems in the detection and screening of the stress wave method and the micro-drill resistance method are solved, the mechanism of the knocking method is further explored, and the use of the knocking method is facilitated. The main contents and innovations of the paper are as follows. First, in view of the problems of the stress wave method and the micro-drill resistance method which are widely used at home and abroad for the verification of the internal defects of the ancient building and wood components, the critical speed of the stress wave and a set of combination of the two kinds of detection techniques are proposed. and the detection method of the internal defect of the wood component is effectively screened. The stress wave velocities of Larix gmelinii, Cunninghamia Lanceolata and Beilschmidia were measured and counted by using the Fakopp stress wave detector, and the critical velocity of the stress wave of the three species was determined by the statistical principle. and the efficiency and the accuracy of the internal defect of the building wood component are screened to a certain extent by the stress wave method. At the same time, the stress wave detection and the micro-drill resistance detection are combined reasonably, the existence and the approximate position of the internal defect of the wood member are determined by the stress wave detection, and the type and the size of the defect are further determined by using the micro-drill resistance detection. The method can quickly and effectively verify the internal defects of the ancient building wood component under the condition that the damage is as little as possible. Secondly, aiming at the low accuracy of the knocking method and the shortage of the experience of the detection personnel, the detection mechanism of the internal defect method of the wood component by using the knocking sound is studied. It is found that the knocking wood component can cause different vibration, and the vibration of the wood component with internal hole defects can be divided into three kinds of vibration modes, such as surface local vibration, integral vibration and defect part vibration. The frequency, amplitude and other parameters of the three kinds of vibration are studied by mechanical vibration model, and the variation and the law of the vibration parameters under different defects are studied. and the various conditions of effectively combining the three kinds of vibration and then simulating actual knocking with the internal cavity defect wood component are analyzed as the basis for the sinking of the internal defect of the wood component. On the basis of the research of the previous knocking detection mechanism, the test of the knocking test of the two kinds of wood component specimens of the cuboid and the cylinder of the larch wood was carried out, respectively. In this paper, the internal defect of wood component is simulated by machining different holes in the later stage, the sound signal is collected and the influence of the internal defect of the wood component on the knocking sound is studied by using the signal analysis. It is found that the characteristic parameters such as square root value and frequency in the sound signal can change with the change of the internal defect and have a certain rule. and the variation law of the characteristic parameters of the sound signal in the knocking test and the variation law of the vibration parameters in the simplified models are consistent within a certain range, and the correctness of the research on the detection mechanism of the knocking is confirmed to a certain extent, so that the internal defects can be screened through the characteristics. The results of the internal defect test of the wood component were screened by using the method of fuzzy pattern recognition and the test data were processed by fuzzy pattern recognition. After the normalization of the test data samples, the establishment of the fuzzy equivalent matrix and the calculation and analysis of the clustering, the signal processing of the internal defect rapid tap screening of the wood component is facilitated, the reliance of the internal defect method of the knocking screening wood component on the experience of the detection personnel is reduced, and meanwhile, the accuracy, the scientificity and the practicability of the method are improved. Finally, the research results are applied to the actual detection of the structure of the wood structure in Beijing, and the better results are obtained.
【学位授予单位】：北京林业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU366.2;TU317
本文编号：2336879
[Abstract]:With the development of science and technology and the actual need, the non-destructive testing technology has been gradually introduced and applied to the field of wood materials from the general industrial fields such as mechanical engineering. The defect of the wood component is one of the important factors that affect the safety performance of the wood structure ancient building. In the long-term use process, due to the characteristics of the wood, the wood component can be decayed, the hole, the crack and other defects due to the factors such as the harmful effect of the harmful organisms and the change of the water content. thereby seriously affecting the usability of the wood member. in that proces of routine detection and evaluation of the wood structure of the ancient building, the internal defect condition of each wood component needs to be quickly screened, namely, the internal condition of the wood component is checked by the non-destructive detection technology, and the presence or absence and the size of the internal defect are preliminarily determined and estimated, and lays a foundation for the accurate detection of the internal defect size and the calculation of the structural safety of the wood structure for the next step. The method for non-destructive screening of the internal defects of the conventional ancient building wood component mainly comprises a knocking method for preliminary screening, a stress wave method for verifying sexual screening and a micro-drilling resistance method, and the like, and the defect is that the accuracy is poor and the detection efficiency is low. In order to better meet the requirement of the internal defect screening of the ancient building and the problems encountered in the practical test, this paper makes a further study on the method of non-destructive screening of the internal defects of the ancient building, such as the stress wave method, the micro-drilling resistance method and the knocking method. The key problems in the detection and screening of the stress wave method and the micro-drill resistance method are solved, the mechanism of the knocking method is further explored, and the use of the knocking method is facilitated. The main contents and innovations of the paper are as follows. First, in view of the problems of the stress wave method and the micro-drill resistance method which are widely used at home and abroad for the verification of the internal defects of the ancient building and wood components, the critical speed of the stress wave and a set of combination of the two kinds of detection techniques are proposed. and the detection method of the internal defect of the wood component is effectively screened. The stress wave velocities of Larix gmelinii, Cunninghamia Lanceolata and Beilschmidia were measured and counted by using the Fakopp stress wave detector, and the critical velocity of the stress wave of the three species was determined by the statistical principle. and the efficiency and the accuracy of the internal defect of the building wood component are screened to a certain extent by the stress wave method. At the same time, the stress wave detection and the micro-drill resistance detection are combined reasonably, the existence and the approximate position of the internal defect of the wood member are determined by the stress wave detection, and the type and the size of the defect are further determined by using the micro-drill resistance detection. The method can quickly and effectively verify the internal defects of the ancient building wood component under the condition that the damage is as little as possible. Secondly, aiming at the low accuracy of the knocking method and the shortage of the experience of the detection personnel, the detection mechanism of the internal defect method of the wood component by using the knocking sound is studied. It is found that the knocking wood component can cause different vibration, and the vibration of the wood component with internal hole defects can be divided into three kinds of vibration modes, such as surface local vibration, integral vibration and defect part vibration. The frequency, amplitude and other parameters of the three kinds of vibration are studied by mechanical vibration model, and the variation and the law of the vibration parameters under different defects are studied. and the various conditions of effectively combining the three kinds of vibration and then simulating actual knocking with the internal cavity defect wood component are analyzed as the basis for the sinking of the internal defect of the wood component. On the basis of the research of the previous knocking detection mechanism, the test of the knocking test of the two kinds of wood component specimens of the cuboid and the cylinder of the larch wood was carried out, respectively. In this paper, the internal defect of wood component is simulated by machining different holes in the later stage, the sound signal is collected and the influence of the internal defect of the wood component on the knocking sound is studied by using the signal analysis. It is found that the characteristic parameters such as square root value and frequency in the sound signal can change with the change of the internal defect and have a certain rule. and the variation law of the characteristic parameters of the sound signal in the knocking test and the variation law of the vibration parameters in the simplified models are consistent within a certain range, and the correctness of the research on the detection mechanism of the knocking is confirmed to a certain extent, so that the internal defects can be screened through the characteristics. The results of the internal defect test of the wood component were screened by using the method of fuzzy pattern recognition and the test data were processed by fuzzy pattern recognition. After the normalization of the test data samples, the establishment of the fuzzy equivalent matrix and the calculation and analysis of the clustering, the signal processing of the internal defect rapid tap screening of the wood component is facilitated, the reliance of the internal defect method of the knocking screening wood component on the experience of the detection personnel is reduced, and meanwhile, the accuracy, the scientificity and the practicability of the method are improved. Finally, the research results are applied to the actual detection of the structure of the wood structure in Beijing, and the better results are obtained.
【学位授予单位】：北京林业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU366.2;TU317
【引证文献】
相关期刊论文 前1条
1 张厚江;管成;文剑;;木质材料无损检测的应用与研究进展[J];林业工程学报;2016年06期
，本文编号：2336879
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