| In recent years,with the acceleration of urbanization in China,the wood used for timber structure building has been increasing year by year.However,due to the large difference in physical and chemical properties of timber used for different timber species,the classification of wood used for timber structure building has brought many difficulties.At present,most Chinese researchers use medical or industrial CT as analysis tools to conduct research on wood properties.However,the existing industrial CT and commonly used medical CT are expensive and inconvenient to move,and the equipment operation is relatively complex,which has high requirements on the operating skills of operators.Although some foreign scientific research institutions have developed some computerized tomography testing equipment and instruments,but the price is expensive and the later maintenance cost is high,so a set of computerized tomography testing equipment with independent intellectual property rights is urgently needed in China to complete the construction materials testing work.Therefore,this thesis developed a CT detection platform which can be used for wood grade classification and structural strength detection and identification of ancient wood structure buildings based on computed tomography scanning technology.By carrying X-ray transmitter,X-ray receiver,object carrying platform and other components on the support vehicle,the scanning detection and scanning data can be realized.The detection platform designed can realize free movement in the region,flexible and convenient,and meet the detection needs of wood structure building.Review domestic and foreign literature and summarize the research status of wood nondestructive testing and CT scanning technology.Analysis and comparison of the current commonly used stress wave detection,ultrasonic detection,vibration detection,X-ray detection and other non-destructive testing technology,and finally choose X-ray detection technology as the main method of platform testing.This paper analyzes the inspection demand of timber structure building and puts forward the overall structure design scheme of CT inspection platform.It is mainly about the hardware structure design of the detection platform,including the design of the mobile support car of the detection platform,the X-ray transmitter,the selection of the X-ray receiver,the design of the rotating lifting structure,the design of the two-way mobile slide structure,the design of the shield structure.According to the motion function of THE CT detection platform,the electrical schematic diagram of the detection platform was drawn,the appropriate PLC and CPU models were selected,the PLC control program was written,and two kinds of lifting and rotating modes were set up to satisfy the lifting and rotating control of the loading platform in different situations,and to realize the scanning work of the building materials used for testing.Based on Visual Studio,the human-computer interaction interface of the system is developed to realize the open and close control of X-ray transmitter and X receiver,the setting of platform motor parameters,the data acquisition of the detection process,and the real-time display of platform running status.The collected data were reconstructed.Experimental results showed that the structural similarity(SSIM)between the reconstructed image and the original drawing of wood structure building materials was 0.956756,that is,about 96%,and the error was less than 5%.The peak signal-to-noise ratio(PSNR)is 39.8248 d B,close to 40,and the resolution of reconstructed image is about 169 dpi,indicating high quality of reconstructed image.According to the quality of reconstructed images,the structure and control system of the CT detection platform designed in this thesis have excellent performance,fully meet the detection requirements,and can provide strong technical support for the classification of wood structure building materials,non-destructive testing,repair and analysis of ancient cultural relics. |
PDF Full Text Request