PSI- Issue 9

I. Shardakov et al. / Procedia Structural Integrity 9 (2018) 199–206 Author name / Structural Integrity Procedia 00 (2018) 000–000

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Then the above mentioned two initial-boundary value problems are solved for the new values of the parameters E, G,  ,  . The restriction of the necessary number of iterations N is determined by the 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 the experimental and calculated values was achieved at the 17th iteration. Fig. 9 shows the eigenmodes, which were used in searching for the model parameters.

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

5. Conclusion An experimental-computational algorithm for determining the elastic and dissipative properties of concrete was proposed. The structural scheme of the experiment and the algorithm for processing the experimental results were developed and realized. Based on the analysis of the three-dimensional deformation process an iterative computational procedure was proposed for determining the elastic and dissipative characteristics of concrete. The reliability and effectiveness of the proposed approach are demonstrated by considering the behavior of a concrete specimen. The proposed approach will open the possibility of analyzing the dependence of the elastic and dissipative properties of materials on frequency, if the developed algorithm is applied for the analysis of specimen response to natural vibrations over several eigenfrequencies. 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). References 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.