Determination Of The Hole Size And Position In Log Using Ultrasonic

With the reduction of the global timber reserves and the increase in demand for timber,more and more attention is focused on the protection of forest resources. For identifying offorest trees defects (especially hole defects) in time is an important task of protecting theforests because it is one of the most serious flows in woods, it could effectively protect theforestry and enhance wood utilization to search for practical detection methods of timber holes.Hole detections of wood on transverse detection based on one-emitting and multi-receiving methods, due to its low costs, high speed, high efficiency and practical features, isone of worthwhile detection methods. In this way, with the comparison between the resultsdetected wood no-flow and the ones of specimens with different size of holes, it is convenientfor one to find which parameters can be used for practical tests. In this essay, taking thereciprocal of amplitude of the first waveform and the amplitude of main-frequency oftransducers as the study parameters, it is possible for making the qualitative and quantitativedetections on transverse of wood.Through the use of way with one-emitting and multi-receiving hole detection methods,due to the significant change of the first waveforms between the no-flows and specimens withdifferent size of holes, one can identify that there is hole in the cross-section of woos.Based on the principal that the further the ultrasonic travels, the greater the energyattenuation of the ultrasonic is. The reciprocal of amplitude of waveform is first introduced inthis study. We noticed that it is possible that the values of reciprocal can behalf of theattenuation of ultrasonic energy. Making use of ultrasonic probe in the receiving point of woodtested for the projection coordinates on the horizontal axis, the reciprocal of amplitude of thefirst waveform as the vertical axis, one can get the figure of closed curve for no-flow wood;and then the ones of specimens with different size of holes. Through the comparison betweenthem, we can find the point at which the two reciprocals have sharp changes. By connectingthe point of ultrasonic emitting-transducer and the points of receiving-transducers with thesharp changes, the sector can be figure out.The travel of ultrasonic on cross-section of wood can be affected by a varieties of factors.There is a negative relationship between the amplitude of main-frequency of transducers andhole-diameters. MATLAB is used for modeling fitting to find the relationship between the twoparameters. Based on them, the size of the hole in the wood could be determined. Based on thepossible area of the hole as well as the calculated diameter of the hole, the exact size andlocation of the hole could be finalized.