Impact hammer-based analysis of nonlinear effects in bolted lap joint

This work presents an experimental investigation into the dynamic behavior of a bolted joint beam configuration. The impact hammer is chosen as an alternative to classical harmonic excitation methods. The structural responses are explored for a range of the joint tightening toques and various levels of impulse hammer excitations. A symmetric beam assembly made of two nominally identical steel beams is studied. Symmetric modes are found to be sensitive to the test parameters. For given torque, impact-based varying joint loading conditions are used to induce the nonlinear joint effects. A linear data processing strategy is used to observe the nonlinear behavior indirectly. The dynamic joint behavior is described in the form of the modal frequency-damping ratio performance maps represented by the two-parametric approximating quadratic response surface models. This model maps the joint conditions on the corresponding dynamic characteristics of interest and it will serve as a basis for the parametric linear joint model development.