Energy Release Protection for Pressurized Systems. Part II: Review of Studies Into Impact/Terminal Ballistics

In order to assess whether or not there is a need for protection against the failure of a pressure system, the engineer must evaluate the hazards associated with rupture. The hazards are divided into two categories: (a) force/displacement and (b) degenerative. Force/displacement is classified into (1) kinetic energy associated with the atmosphere: blast, (2) kinetic energy of objects (fragmentation and impact of missiles), and (3) kinetic energy associated with foundations: soil foundation motion. The first article of this series [Energy release protection from pressurized systems: Part I Review of studies into blast and fragmentation, Appl Mech Rev38 (Dec), 1625–1651 (1985)] has set the stage for this paper, which reviews the studies into predicting the performance (mechanics) of a receptor (target, containment, barricade, shelter) that is impacted by a missile. The study into the prediction of target missile performance or terminal ballistics has occupied interests of man since the development of a projectile as a weapon. One of the earliest publications of terminal ballistics is reported by Robins (1742). A number of experimental studies during the 1800s are reported by Holie (1950). These early experiments set the pattern for the reliance on experimental programs to define semiempirical formula to predict missile–target responses (such as penetration, perforation, spalling, and scabbing) into the 20th century. This is due to the fact that theoretically derived equations to predict missile target performance have enjoyed only limited success because of the complexity of the problems to be solved. Numerical methods essentially had to wait for the development of the high speed digital computers in the early 1960s. Historically the finite difference methods have received the earliest use in simulating impact. They tend to be more computationally cost effective than finite element programs. However, because of the generality of the finite element method to idealize structures geometrically for a considerable range of mechanics problems, it has received the greater attention of research and development over the last two decades and is capable of solving wave propagation, nonlinear material, and nonlinear large deformation problems. The computer codes developed to solve impact problems are generally characterized as either Lagrangian or Eulerian. In this paper, a brief discussion will be provided covering the development of target/missile formulas, associated experimental programs and numerical methods.