An Experimental Study on the Effect of Fatigue Loading on Electrical Impedance in Open-Hole Carbon Nanofiber-Modified Glass Fiber/Epoxy Composites

2021 ◽  
pp. 114463
Author(s):  
Ishan T. Karnik ◽  
Tyler N. Tallman
Author(s):  
I. T. Karnik ◽  
T. N. Tallman

Abstract Composite materials are ideal for many weight-conscious applications such as aerospace and automotive structures because of their exceptionally high specific properties. However, composite materials are susceptible to complex damage and difficult-to-predict damage growth. This necessitates the application of structural health monitoring (SHM) for in-operation monitoring of damage formation and accumulation. Self-sensing materials are strong candidates for composite SHM because they do not suffer from limitations associated with traditional, point-based sensors. A common approach to self-sensing is the piezoresistive effect in nanofiller-modified materials. To date, work in the area of self-sensing via the piezoresistive effect has focused overwhelmingly on the direct current (DC) response of these materials. This is an important limitation because alternating current (AC) effects inherently provide more information by relating both impedance and phase to damage. Therefore, this work explores the effect of high-cycle fatigue loading on the AC response of carbon nanofiber (CNF)-modified glass fiber/epoxy laminates. Specifically, impedance magnitude and phase angle are both measured through the thickness and along the length of a tension-tension fatigue-loaded specimen with an open-hole stress concentration as a function of load cycle and up to 10 MHz. The collected impedance data is then fit to an equivalent circuit model and correlated to stiffness changes. This means that changes in equivalent circuit behavior can be used to track fatigue-induced softening in self-sensing composites. In light of these promising preliminary results, AC effects appear to have considerable potential for real-time tracking of damage accumulation.


Author(s):  
Nguyen Trung Thanh

The tube is made of polymer composite material based on K-153 epoxy resin (K-153 epoxy resin is made from ED-20 epoxy resin modified by thiokol and oligomer acrylate), T-13 glassfiber, hardener polyethylenepolyaminemade by wrapping on machine. The effect of drying temperature on mechanical properties (tensile strength, flexural strength) of polymercomposite materialwas studied. The paper also mentions to select suitable hardener to beused for polymercomposite tube wrapping. The results show that the strength at break, flexural strength of polymercomposite material are changedmuch when changing wrapping angle. The drying temperature increases, the curing time of polymercomposite material is much reduced. The time to stabilize after drying also greatly affects the pressure resistance of polymer composite tubes. Keywords Polymercomposite, K-153, tensile strength, flexural strength, pressure resistance. References [1] M. J. Mochane, T. C. Mokhena, T. H. Mokhothu, Recent progress on natural fiber hybrid composites foradvanced applications: A review, eXPRESS Polymer Letters 13 (2) (2019) 159-198.[2] J. Kim, H. J. Yoon, K. Shin, A study on crushing behaviors of composite circular tubes with different reinforcing fibers, International Journal of Impact Engineering 38(4) (2014) 198-207.[3] T. D. Jagannatha1, G. Harish, Mechanical Properties of carbon/ glass fiber reinforced epoxy hybrid polymer composites, Journal of Reinforced Plastics and Composites 4 (2) (2015) 131–137.[4] Vitalii Bezgin, Agata Dudek, Composites based on high-molecular weigh epoxy resin modified with polysulfide rubber, Composite Theory and practice 17(2) (2017) 79-83. [5] Abdouss, Majid, Farajpour, Tohid, Derakhshani, Morteza, The Effect of Epoxy-Polysulfide Copolymer Curing Methods on Mechanical-Dynamical and Morphological Properties, Iran. J. Chem. Chem. Eng. 30(4) (2011) 37-44.[6] G. Devendhar Rao, K. Srinivasa Reddy, P. Raghavendra Rao, Mechanical properties of E-glass fiber reinforced epoxy composites with SnO2 and PTFE, International Journal of Emerging Research in Management and Technology 6 (7) (2017) 208-214.[7] Hu Dayong, Jialiang Yang, Experimental study on crushing characteristics of brittle fibre/epoxy hybrid composite tubes, International Journal of Crashworthiness 15(4) (2010) 401-412 .[8] G.U. Raju, S. Kumarappa, Experimental Study on Mechanicaland Thermal Properties of Epoxy Composites Filled with Agricultural Residue, Polymers from Renewable Resources 3 (3) (2012) 118–138.          


Sign in / Sign up

Export Citation Format

Share Document