ISSN:
1573-2703
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mathematics
,
Technology
Notes:
Summary A mathematical model is proposed, apparently for the first time, for the onager, a late Roman catapult. The elastic energy of the machine is contained in a cylindrical bundle of twisted elastic cords, and, although each cord satisfies a linear stress-strain law, the geometry of the entire bundle causes a torque to be exerted on the moving arm of the onager which is a nonlinear function of the angular deflection of the arm. This torque is used in the nonlinear differential equations of motion which are integrated numerically. Experimental work is described which assists in determining the torque, and in addition supplies ranges for the projectiles for various masses, sling lengths and finger angles (parts of the release mechanism). Predictions from the mathematics are in reasonable agreement with experiment. A new calibration rule for the onager is proposed, based on the numerical integrations, which complements that known since classical times for the two-armed Greek palintone. Finally an appendix contains a discussion of the effect of a buffer on the motion.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00044610
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