Vibration analysis of single lap adhesive joint: Experimental and analytical investigation

An analytical model to study the coupled transverse and longitudinal vibrations of a single lap adhesive joint is described in this paper, which includes partial differential form of the motion equations. A joint consists of two identical adherents of mild steel that are lap jointed over a certain length by a viscoelastic material, epoxy resin (araldite). Adherents are modeled as Euler-Bernoulli free-free beam. Both transverse and axial deformation of adherents and longitudinal shear and transverse peel stresses at the adhesive joint interface are considered in deriving the equations of motion. The numerical solutions of the governing equations for free vibrations yield the system's natural frequency and mode shapes. Experimentation was carried out on both monolithic and adhesively jointed beams to observe the effect of the joint; natural frequencies of the system were measured experimentally and compared with those obtained theoretically. The fundamental frequency of a free-free jointed beam was more sensitive to joint overlap ratio. However natural frequency depended on the accelerometer location in the system, which was attributed to its mass contribution to the overall system mass. Theoretical frequency response function is generated for a beam with and without accelerometer mass to show the mass loading effect of the transducer (accelerometer).