Research On Correlation Of Modulus Of Elasticity By Non-Destructive Testing For Natural Larch

Non-destructive testing that doesn't damage use performance of the tested object is a effective method of detecting material by various physical principles and chemical phenomena, has some advantages including short measuring time, simple method, high stability, no destructing lumber and requirements of continuous production, and has been widely used in the field of wood science and engineering. We study mechanical properties of wood by non-destructive testing and grading by wood strength. It couldn't only understand the performance of different non-destructive testing in the test of mechanical properties, but also bring about significant promotion in wood utilization, production costs and production efficiency, that has important theoretical significance and economic value.In this paper, mechanical performance tests were made by three visual codes-Japanese, German, American and vibration-transverse, longitudinal, stress wave, MSR. After that, analyzing the test results, and research into the characteristics among different visual testing methods, the correlation among different non-destructive testing methods and the correlation between visual testing and non-destructive testing. It will provide theoretical principle for establishing combined grading prediction model to obtain the optimum combination of visual testing and non-destructive testing in subsequent destructive testing. The main conclusions are as follows:(1) The require of visual grade is the strictest by Japanese code, followed by German code, that is the loosest by American code.(2) As the grade of decline, the average elastic modulus of each visual grade is on the decline.(3) In the range of 7-29Gpa for modulus and 500-900 Kg/m3 for average density, the frequency distribution of the sample is consistent with skewed normal distribution.(4) There is a very strong correlation between simply supported beam vibration and MSR, and the maximum correlation coefficient is 0.9616.(5) There is a strong correlation between the combination of Kus+p+Q and simply supported beam vibration, and the maximum correlation coefficient is 0.7859. There is a strong correlation between the combination of KDE+P+Q and stress wave, and the maximum correlation coefficient is 0.7767.