Analysis of the Design Criteria for Ancient Greek and Roman Catapults

This paper will give a short overview of use of COMSOL Multiphysics for analyzing ancient Greek and Roman catapults with the main focus on the energy storing torsion springs. Catapults have been known and used in the Greek and Roman world from around 399 BC and a fully standardized design for powerful torsion catapults emerged around 270 BC, based on one basic factor, the diameter of the torsion springs. This value is then scaled to give all vital structural dimensions of the catapult. How optimal this design is has until now not been fully understood and earlier work has been dominated by trial-and-error methods. The use of COMSOL Multiphysics enables the construction of virtual catapults parts, non-linear analysis of structural parts where no analytical solution is known as well the analysis of the surviving designs, with respect to optimal performance. The result from COMSOL Multiphysics is compared to a traditional analysis and to data obtained from Sigma X Section software.