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Mathematical Problems in Engineering
Volume 2017 (2017), Article ID 4393279, 11 pages
https://doi.org/10.1155/2017/4393279
Research Article

Research on NDT Technology in Inference of Steel Member Strength Based on Macro/Micro Model

1State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China
2Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of Mining and Technology, Xuzhou 221116, China
3National Space Frame and Steel Structures Quality Supervision and Inspection Center, Xuzhou 221006, China

Correspondence should be addressed to Beidou Ding

Received 10 February 2017; Revised 5 June 2017; Accepted 11 June 2017; Published 16 July 2017

Academic Editor: Marek Lefik

Copyright © 2017 Beidou Ding et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In consideration of correlations among hardness, chemical composition, grain size, and strength of carbon steel, a new nondestructive testing technology (NDT) of inferring the carbon steel strength was explored. First, the hardness test, chemical composition analysis, and metallographic analysis of 162 low-carbon steel samples were conducted. Second, the following works were carried out: quantitative relationship between steel Leeb hardness and carbon steel strength was studied on the basis of regression analysis of experimental data; influences of chemical composition and grain size on tension properties of carbon steel were analyzed on the basis of stepwise regression analysis, and quantitative relationship between conventional compositions and grain size with steel strength was obtained; according to the macro and/or micro factors such as hardness, chemical compositions, and grain size of carbon steel, the fitting formula of steel strength was established based on MLR (multiple linear regressions) method. The above relationships and fitting formula based on MLR method could be used to estimate the steel strength with no damage to the structure in engineering practice.