![]() For this purpose, experimental studies were conducted on two different types of SLJ samples, the first type with identical upper and lower adherend thicknesses and the second with different upper and lower adherend thicknesses. In the present study, mechanical properties of different single lap joint configurations derived from adherends with different thicknesses subjected to tensile loading were investigated experimentally and numerically. ![]() Early detection of the stresses and rupture in the joint are crucial for the prevention of damage to the system. The effects of the length of adherend, width of adherend, the overlapping length of the joint, the thickness of the adhesive layer and the initial impact velocity of the impacted mass on the double lap adhesive joint are studied. The ability to achieve strength of adhesive joint is essential to the optimal maintenance of whole system with respect to cost and productivity. One of the major concerns in adhesive joint is the detection of the rupture initiation and strength of joint before it develops into a failure of material. This generally leads to unscheduled shut down thereby increasing the cost of operations. Joint failure is one of the main causes of interruption of rotating or stationary machinery operation. Stress and deformation of the double lap adhesive joint is obtained by finite element analysis using ANSYS and strength is obtained by experimental method. Lap splice sites on a typical Boeing KC-135 panel with low composite thermal inertia values had high skin-thickness losses from corrosion.- This paper summarizes the evaluation of stress and strength of double lap adhesive joint. Late time composite thermal inertia maps depict where corrosion-related thickness losses occur. Composite thermal inertia maps characterize shallow skin defects within the lap splice at early times (0.4 s). We map the fuselage composite thermal inertia, based on the (inverse) slope of the surface temperature versus inverse square root of time. We show tables, charts and temperature maps of typical lap splice material losses for the riveted (and bonded) Boeing 737, and the riveted (but unbonded) Boeing KC-135. ![]() = 5 % material loss at 0.4 s after the heat flash. Along with the advantages in data acquisition, the low frequency technique is relatively insensitive to minor surface curvature and to ultrasonic interference effects caused by adhesive bondline thickness variations in the lap splice. With the low frequency technique, interface echoes of the lap splice are not resolved and gating of the signal is unnecessary this in itself makes the technique simple to implement and saves considerable more ยป time in data acquisition. Low frequency, in this context, refers to a wavelength that is greater than the lap splice`s layer thicknesses. C-scans produced by this technique are color representations of the received signal`s peak-to-peak amplitude (voltage) taken over an (x, y) grid. The inspection technique uses a computer-controlled data acquisition system to produce a C-scan image of a radio frequency (RF) waveform created by a low frequency, broadband, focused beam transducer, driven with a spike voltage pulser. The ultrasonic prototype consists of a normal incidence, low frequency inspection technique, and a scanning adapter that allows focused immersion transducers to be operated in a direct contact manner in any inspection orientation, including upside-down. ![]() This thesis is a collection of research efforts in ultrasonics, conducted at the Center for Aviation Systems Reliability located at Iowa State University, as part of the Federal Aviation Administration`s ``Aging Aircraft Program.`` The research was directed toward the development of an ultrasonic prototype to inspect the aluminum/adhesive fuselage lap splices found on 1970`s vintage Boeing passenger aircraft. ![]()
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