Dynamic Response of a Munition to a Low Pressure Airbag

A mathematical model of a collidants impacting a low pressure airbag is derived. This model r epresents a simplification of the physics for a bomb bay ejector airbag. This model uses a single , yet mathematically complicated element rather than thousands of mathematically simple elements the way the finite element method does. Our design -oriented model is solved with less microprocessor time than the finite element method to which it will be compared . Nomenclature �Q = Heat transfer by cond uction across airbag surface �W = Work done on the system by external forces cp = Constant pressure heat capacity of gas per change in temperature cv = Constant volume heat capacity of gas per change in temperature T = Temperature of the gas in the airbag t = Time dE = System change in Energy m = Mass of gas in the airbag m = Mass flow rate of gas into (+) or out of ( -) the airbag dU = Change of Internal Energy of gas in Airbag � = T