PSI - Issue 13

I. Shardakov et al. / Procedia Structural Integrity 13 (2018) 1342–1346 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

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The restriction of the necessary number of iterations N is determined by a condition for achieving a specified difference between the experimental and calculated values of the eigenfrequecies of natural vibrations, and also between the experimental and calculated values of the logarithmic damping decrement. Table 1 compares the calculated frequencies and logarithmic decrements with the experimentally measured ones. The agreement between experimental and calculated values was achieved at the 17th iteration. Fig. 9 shows the eigenmodes, which were used in searching for model parameters. The fields of the displacement vector amplitude obtained in simulation are represented in Fig. 5. Table 1. Parameter Computation Experiment long f , Hz 4882 4881.9 long  33.38e-3 33.38e-3 rot f , Hz 5630 5629.7 rot  39.25e-3 38.50e-3

a

b

Fig.5. (a) The fields of the displacement vector amplitude for longitudinal eigenmode ; (b) idem for torsional eigenmode

5. Conclusion

An experimental-computational algorithm for determining elastic and dissipative properties of concrete was proposed. A structural scheme of the experiment and an algorithm for processing experimental results were developed and realized. Based on analysis of three-dimensional deformation process an iterative computational procedure was proposed for determining elastic and dissipative characteristics of concrete. The reliability and effectiveness of the proposed approach were demonstrated by considering the behavior of a concrete specimen. Model parameters were obtained for description of elastic and dissipative properties of concrete at frequency range of 5.6±0.5 kHz. Proposed algorithm realized at higher frequencies can be used to determine frequency dependence of elastic and dissipative characteristics. Acknowledgements The research was performed at the Institute of Continuous Media Mechanics Ural Branch of Russian Academy of Science, with the support of the Russian Science Foundation (project №14 -29-00172). ASTM C215 - 14, 2016. Standard Test Method for Fundamental Transverse, Longitudinal, and Torsional Resonant Frequencies of Concrete Specimens, West Conshohoken, Pa, USA. ASTM C597/C597M - 16, 2016. Standard Test Method for Pulse Velocity through Concrete, West Conshohoken, Pa, USA. Bykov, A.A., Matveenko, B.P., Serovaev, G.S., Shardakov, I.N., Shestakov, A.P., 2015. Mathematical modeling of vibration processes in reinforced concrete structures for setting up crack initiation monitoring. Mechanics of Solids, 50(2), 160 - 170. Ignat'kov, D.A., 2011. Determination of the characteristics of the elasticity of heterogeneous materials using the dynamic method. Surface Engineering and Applied Electrochemistry, 47(1), 53 - 62. Lee, B.J., Kee, S. - H., Oh, T., Kim, Y. - Y., 2017. Evaluating the Dynamic Elastic Modulus of Concrete Using Shear - Wave Velocity Measurements. Advances in Materials Science and Engineering, 2017. Ng, C.T., Veidt, M., 2009. A Lamb - wave - based technique for damage detection in composite laminates. Smart Mater. Struct. 18 (7). Nowatski, W., The Theory of Elasticity, 1975, Moscow, Mir, pp. 872 Zheng, L., Huo, X.S., Yuan, Y., 2008. Experimental investigation on dynamic properties of rubberized concrete. Construction and Building Materials, 22(5), 939-947. References