An analytical-numerical method to analyze single degree of freedom models under airblast loading

In this paper, an analytical-numerical method to predict the response of a linear spring-mass system without damper, excited by a family of pulse loads, is proposed. The external loading is described by a four parameter expression, involving the peak overpressure, the loading duration and two parameters which characterize the pulse shape (lambda and gamma). A parametric analysis for ranges of pulse shape parameters suitable to describe a wavefront pressure profile produced by an airblast from high explosives is developed. The influence of the pulse shape on the dynamic load factor representation of structural response and on pressure-impulse isodamage curves is graphically shown. An expression of the transient response spectrum generated by a typical exponentially decaying load (lambda = 1, gamma = 2.8) is proposed, and a discussion about the formulation of a general expression for the transient response spectrum is introduced. Various features of the spectrum and pressure-impulse diagrams are analyzed, and all the problems concerning the building of graphics are discussed. Finally, a review of existing simplified isodamage curves is reported and an existing method to eliminate pulse shape effects, the effective pressure-impulse diagram, is discussed. (c) 2006 Published by Elsevier Ltd.