A new approach for fatigue damage detection in adhesive joints modified with nanoparticles under different temperatures

Abstract

Scarf adhesive joints (SAJs) in carbon fiber composites were fabricated with 5° taper angle and bondline thickness of 0.17 mm. The joints are modified with SiC‐nanoparticles and characterized through tensile and fatigue loading at room temperature (RT) and 50°C. The analysis of the hysteresis loop in terms of loss and storage moduli, potential and dissipated energies, and damping factor is a quite new topic and one of the important goals of this study. At RT, the fatigue limit of the SAJs was improved by 55% when the bondline thickness decreased from 0.25 to 0.17 mm and further enhanced by 22% with SiC incorporation. For the first time, the evolution of the potential energy versus fatigue cycles of the SAJs can be modeled for early predicting joint life and hence helps in preventing their sudden failure. At 50°C, the fatigue strength of the SiC‐SAJ is approximately equal to the unmodified joint at RT.

Potential energy as a new approach for detection and monitoring of fatigue damage in scarf adhesive joints modified with nanoparticles

“…Hence, the phase shift angle (δ) is computed by subtracting the "h" values of the strain and the stress equations. Khashaba et al 16,52 found good agreement between the predicted phase shift angle (δ) using equation (25) and that calculated using equation ( 6) via the developed Excel codes.…”

“…The current study built on the insights of Khashaba et al 16,52 who have validated the estimated damping factors from the developed Excel codes by fitting the measured sinusoidal stress and strain data to the following sine functionwhere k, a, and b are coefficients and θ is the cycle angle (0 to 2 π ), and h is the horizontal shift angle. When h is added to θ, the maximum stress (or strain) occurs at π / 2 , 3 π / 2 and the minimum at 0, π , 2 π .…”

“…After an extensive review of the literature, it has been found that there is no available data on the dynamic performance of the scarf adhesive joint yet except of the author works. 16,21,24,52 Therefore, data about the damping factor (tan δ) of some different types of adhesively bonded joints are collect and compared with those of the SAJs, as shown in Table 6. It is obvious from Table 6 that the damping factors of the SAJs are in the range of some SLJs, which were determined using free vibration decay method, as shown in Table 6.…”

“…The current study built on the insights of Khashaba et al 16,52 who have validated the estimated damping factors from the developed Excel codes by fitting the measured sinusoidal stress and strain data to the following sine function…”

A nonlocal elasticity theory to model the static behaviour of edge-cracked nanobeams

“…Moreover, nanostructures find application in composite materials, where one or more phases, having a nanometer scale, are embedded in a matrix. In terms of their matrix, nanocomposites are generally classified as [3]: ceramic-matrix [4][5][6][7][8][9][10][11][12], metalmatrix [13][14][15][16][17][18][19][20][21] and polymer-matrix nanocomposites [22][23][24][25][26][27][28]. More recently, research on cement-based materials (including concrete, mortar and cement paste) [29][30][31][32][33][34][35] has been trying to exploit the synergies that nanostructures can provide in terms of both improvement of their performance and acquisition of "smart" functions, making cement-based products become electric/thermal sensors or crack repairing materials [36].…”