Damage detection of unidirectional carbon fiber–reinforced laminates with embedded magnetostrictive particulates: A preliminary study

Abstract

Defects in composite laminates are difficult to detect because of the conductive and paramagnetic properties of composite materials. Timely detection of defects in composite laminates can improve reliability. This research illustrates the preliminary analysis and detection of delaminations in carbon fiber laminate beams using a single layer of magnetostrictive particles and noncontacting concentric magnetic excitation and sensing coils. The baseline analytical models also begin to address the intrusive nature of the magnetostrictive particles as well as relate the applied excitation field with the stress and magnetic flux densities induced in the magnetostrictive layer. Numerical methods are used to begin to characterize the presence of magnetostrictive particles in the laminate and the behavior of the magnetostrictive particles in relationship to the magnetic field used during sensing. Unidirectional laminates with embedded delaminations are used for simulations and experimentations. A novel, yet simplified fabrication method is discussed to ensure consistent scanning and sensing capabilities. The nondestructive evaluation scanning experiments were conducted with various shapes and sizes of damages introduced into carbon fiber-reinforced polymeric composite structures. The results demonstrate high potential for magnetostrictive particles as a low-cost, noncontacting, and reliable sensor for nondestructive evaluation of composite materials.

Detection of damage precursors with embedded magnetostrictive particles

“…In addition, the 300 mm particles size, which is larger than ply thickness (250 mm), may have exacerbated the loss in mechanical properties of the laminate. This observation is contrary to some studies (see Myers et al, 2012) that have shown that embedding TD particles increase the ultimate strength of CFRP systems without appreciable loss in stiffness. Table 1 shows the tensile test results obtained in this experiment.…”

“…Analytical and numerical models also exist to characterize the response of MS particles with respect to external magnetic field or load (Calkins et al, 2007;Carman and Mitrovic, 1995;Dapino et al, 2000Dapino et al, , 2002Datta et al, 2008;Myers et al, 2012;Zhou et al, 2013).…”

“…The inverse is also true; magnetization occurs because of applied external load. This bi-directional coupling between magnetic and mechanical states of a MS material provides a transduction capability that has been used in various applications (Duenas and Carman, 2000; McCombe et al, 2009) including sensing composite damage (Chen and Anjanappa, 2006; Giurgiutiu et al, 2001; Krishnamurthy et al, 1999; Myers et al, 2012; Wong and Shin, 2008).…”

Enhancement of the Excitation Efficiency of the Non-Contact Magnetostrictive Sensor for Pipe Inspection by Adjusting the Alternating Magnetic Field Axial Length

“…The quantitative relationship between the axial length of the excitation magnetic field and the excitation efficiency of the non-contact MsS used in GWT can only be obtained through experiments. A comprehensive finite element model or theoretical model [ 22 – 24 ], including all the parameters in the inspection progress, is needed for the quantitative analysis. This will be the topic in further research.…”

Experimental fabrication and nondestructive testing of carbon fiber beams for delaminations using embedded Terfenol-D particles

“…The test specimens were designed with dimensions that allowed nondestructive testing using the apparatus in Myers et al (2013), where the length and height dimensions were 9.75 in 3 1 in (247.65 mm 3 25.4 mm), respectively. The ply count is not constant as in Myers et al (2013) and ranges from 2 to 14 plies. The beams' dimensions were designed as in Myers (1996) to have a natural frequency of 10 Hz, but the ply counts vary along with the natural frequency for these specimens.…”