Mechanical and electromagnetic emissions related to stress-induced cracks

The present research focuses on acoustic emission (AE) and electromagnetic emission (EME) detected during laboratory compression tests on concrete and rocks specimens. We investigated their mechanical behavior up to failure by the AE and EME due to micro- and macrocrack growth. Among the tested specimens, a concrete sample was analyzed by applying to its surface both piezoelectric (PZT) transducers for detection of high-frequency AE waves, and PZT accelerometric transducers for detection of low-frequency AE (elastic emission or ELE). Besides the high-frequency AEs, the emergence of low-frequency ELE just before the failure describes the transition from diffused microcracking to localized macrocracks which characterizes the failure in brittle materials. For all the specimens, a simultaneous analysis of magnetic activity was performed by a measuring device calibrated according to metrological requirements. In all the considered specimens, the presence of AE events has been always observed during the damage process, whereas it is very interesting to note that the EMEs were generally observed only in correspondence with sharp stress drops or the final collapse. The experimental evidence confirms AE and EME signals as collapse precursors in materials like concrete and rocks.

[1]  R. Chéret,et al.  Shock waves in solids: an evolutionary perspective , 1999 .

[2]  A. Carpinteri.  Scaling laws and renormalization groups for strength and toughness of disordered materials , 1994 .

[3]  K. Iyer,et al.  Electromagnetic emission during the fracture of heat-treated spring steel , 1988 .

[4]  Avinoam Rabinovitch,et al.  Surface oscillations — A possible source of fracture induced electromagnetic radiation , 2007 .

[5]  Giuseppe Lacidogna,et al.  Analysis of acoustic emissions at low frequencies in brittle materials under compression , 2009 .

[6]  A. Rabinovitch,et al.  Fracture induced electromagnetic radiation , 2003 .

[7]  Giuseppe Lacidogna,et al.  Structural damage diagnosis and life-time assessment by acoustic emission monitoring , 2007 .

[8]  A. Carpinteri.  Cusp catastrophe interpretation of fracture instability , 1989 .

[9]  Giuseppe Lacidogna,et al.  Acoustic and Electromagnetic Emissions as Precursor Phenomena in Failure Processes , 2011 .

[10]  S. Puzzi,et al.  From criticality to final collapse: Evolution of the ''b-value" from 1.5 to 1.0 , 2009 .

[11]  Steven Gregory O'keefe,et al.  A mechanism for the production of electromagnetic radiation during fracture of brittle materials , 1995 .

[12]  Michael Forde,et al.  Assessing Damage of Reinforced Concrete Beam using b -value Analysis of Acoustic Emission Signals , 2003 .

[13]  M. V. M. S. Rao,et al.  Analysis of b-value and improved b-value of acoustic emissions accompanying rock fracture , 2005 .

[14]  Giuseppe Lacidogna,et al.  Morphological Fractal Dimension Versus Power-law Exponent in the Scaling of Damaged Media , 2009 .

[15]  Masayasu Ohtsu,et al.  bQuantitative evaluation of fracture processes in concrete by the use of improved -value , 2000 .

[16]  Masayasu Ohtsu,et al.  The history and development of acoustic emission in concrete engineering , 1996 .

[17]  S. Puzzi,et al.  Critical defect size distributions in concrete structures detected by the acoustic emission technique , 2008 .

[18]  Katsunori Fukui,et al.  Electromagnetic Radiation from Rock During Uniaxial Compression Testing: The Effects of Rock Characteristics and Test Conditions , 2005 .

[19]  A. Pollock.  Acoustic emission - 2: Acoustic emission amplitudes , 1973 .

[20]  John A. Hudson,et al.  SOFT, STIFF AND SERVO-CONTROLLED TESTING MACHINES: A REVIEW WITH REFERENCE TO ROCK FAILURE , 1972 .

[21]  A. Misra.  A physical model for the stress-induced electromagnetic effect in metals , 1978 .

[22]  Martin Larcher,et al.  Development of Discrete Cracks in Concrete Loaded by Shock Waves , 2009 .

[23]  A. Misra.  Theoretical study of the fracture-induced magnetic effect in ferromagnetic materials , 1977 .

[24]  Alberto Carpinteri,et al.  Mechanical damage and crack growth in concrete: Plastic collapse to brittle fracture , 2011 .

[25]  John B. Rundle,et al.  Statistical physics approach to understanding the multiscale dynamics of earthquake fault systems , 2003 .

[26]  A. Carpinteri.  A catastrophe theory approach to fracture mechanics , 1990 .

[27]  Giuseppe Lacidogna,et al.  Critical Behaviour in Concrete Structures and Damage Localization by Acoustic Emission , 2006 .