TABLE OF CONTENTS This chapter discusses the interpretation of shock measurements and the reduction of data to a form adapted to further engineering use. Methods of data reduction also are discussed. A shock measurement is a trace giving the value of a shock parameter versus time over the duration of the shock, referred to hereafter as a time-history. The shock parameter may define a motion (such as displacement, velocity, or acceleration) or a load (such as force, pressure, stress, or torque). It is assumed that any corrections that should be applied to eliminate distortions resulting from the instrumentation have been made. The trace may be a pulse or transient. Concepts in vibration data analysis are discussed in Chap. 22.
Examples of sources of shock to which this discussion applies are earthquakes (see Chap. 24), free-fall impacts, collisions, explosions, gunfire, projectile impacts, high-speed fluid entry, aircraft landing and braking loads, and spacecraft launch and staging loads.
Often, a shock measurement in the form of a time-history of a motion or loading parameter is not useful directly for engineering purposes. Reduction to a different form is then necessary, the type of data reduction employed depending upon the ultimate use of the data.
Comparison of Measured Results with Theoretical Prediction. The correlation of experimentally determined and theoretically predicted results by comparison of records of time-histories is difficult. Generally, it is impractical in theoretical analyses to give consideration to all the effects which may influence the experimentally obtained results. For...
