Technical Brief

Mechanical Behavior and Performance of the Onager

[+] Author and Article Information
Arcangelo Messina

Dipartimento di Ingegneria dell'Innovazione,
Università del Salento,
Lecce 73100, Italy

Cesare Rossi

Dipartimento di Ingegneria Industriale,
Università di Napoli “Federico II”,
Napoli 80125, Italy
e-mail: cesare.rossi@unina.it

Contributed by the Mechanisms and Robotics Committee of ASME for publication in the JOURNAL OF MECHANICAL DESIGN. Manuscript received May 9, 2014; final manuscript received December 2, 2014; published online January 15, 2015. Assoc. Editor: Oscar Altuzarra.

J. Mech. Des 137(3), 034501 (Mar 01, 2015) (5 pages) Paper No: MD-14-1276; doi: 10.1115/1.4029319 History: Received May 09, 2014; Revised December 02, 2014; Online January 15, 2015

In this paper, the mechanical behavior and performance of the onager, an ancient war machine, are analyzed. This study is based on torsional motors, as previously described. Because the onager has been investigated very little in modern times and the details given by ancient engineers are very scarce, this study starts from the available literature of both ancient and modern times. The mathematical models are developed through analytical mechanics along with integrations carried out numerically. Simulations performed provide interesting results which are in good agreement with the information recorded by ancient historians, and thus validating conjectures regarding the design of these machines. Finally, this investigation clarifies the role and effectiveness of these machines in ancient warfare, helping to understand many aspects of both ancient engineering design and historical events.

Copyright © 2015 by ASME
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Grahic Jump Location
Fig. 1

Pictorial reconstruction of the onager and details of the sling linkage

Grahic Jump Location
Fig. 2

Working principle of the onager

Grahic Jump Location
Fig. 3

Nomenclature in the generic configuration of the onager

Grahic Jump Location
Fig. 4

Onager: trajectories for θund = 110 deg

Grahic Jump Location
Fig. 5

Onager: trajectories for θr = 95 deg



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