Modern experimental study of the shields of Achilles & Aias in Homer

Below I present the research of the professor of engineering of the University of Patras Dr. Stefanos Paipetis as published in the magazine "Trito Mati" (issuee 118, 2003), about the defensive weapons of the Greeks and specifically with two descriptions of shields, which display elements of a know-how that reaches the levels of modern technological knowledge! These examples are found in the eminent war epic, the Iliad.

The shields from the Homeric verses in the modern laboratory

These examples concern the shields of Achilles and Aeandus of Telamonius. Both are laminated structures, ie they consist of overlapping sheets or layers of materials with different properties, properly connected to each other, so that in the end the properties of the construction are highly upgraded compared to a structure made of a single material. Such constructions are widely used today in modern industrial and aerospace constructions.

But the operation of each of these shields is based on a different principle of mechanical science. In order to study each shield as a laminated structure, the development of a theoretical model was required. Especially for the shield of Ajax (Aias), the required materials were not prohibitive from an economic point of view, as for the shield of Achilles. Thus, the physical model could be constructed, ie a complete series of essays, the behavior of which was tested experimentally!

The development of the models was based on a series of assumptions, which, however, were completely realistic. For example, that the overlapping layers were even, that the total weight of the shield did not exceed the capabilities of the person using it, even if he was a demigod, that the kinetic energy of the spear, at the moment it struck the shield, was as about the javelin holder who holds the world record in the respective sport, etc.

The texts of the Iliad are, as we shall see, extremely enlightening and provide sufficient data to be used as a starting point for the numerical simulation of each weapon and its behavior: A spear with a hard bronze tip (tin brass) struck the shield . Although the exact geometry of the shield and the spear is not exactly known, archaeological finds provide important evidence, as schematic and pictorial representations can be extremely eloquent.

The exact properties of the relevant materials were determined relatively easily, either through the correspondence to modern materials with similar composition and production methods or through experimental determination. Finally, the investigation of the properties and behavior of the shields was done by the numerical solution of the problem of the dynamic contact between them and the spear. This problem has attracted the attention of researchers over the past two decades, as it concerns high-velocity missile strikes, nuclear weapons design and analysis, nuclear reactor safety, rapid metal shaping and much more, and has led to the development of new, advanced algorithms and computer codes.

The shield of Axilles

The information given in the Iliad about the shield of Achilles, apart from the long description of its external representations, is the following:

a) The first description of a robot in history (Isaac Asimov's view of the golden girls who helped Hephaestus, 1412-1422):

Και τες φυσούνες μάκρυνεν απ' την φωτιά και όλα
εσύναξε τα σύνεργα σ' εν' αργυρό λαρνάκι,
και με σφουγγάρι εκάθαρε το πρόσωπο, τα χέρια,
τον τράχηλον τον δυνατόν, τα δασερά του στήθη.
Χιτώνα ενδύθη, εφούχτωσε σκήπτρο παχύ κι εβγήκε
χωλαίνοντας και ανάλαφρα τον κύριον εστηρίζαν
θεράπαινες ολόχρυσες, σαν ζωντανά κοράσια.
Δύναμιν έχουν και φωνήν, νουν έχουν εις τες φρένες,
και τεχνουργήματ' έμαθαν από τους αθανάτους.
Εκείνες τον επρόσεχαν. Κι εσυρθη αυτός πλησίον
στη Θέτιδα κι εκάθησε σ' ένα θρονί ωραίο.

Είπε και αυτού την άφησε και πήγε στες φυσούνες,
στο πυρ τες στρέφει και γοργά να εργάζονται προστάζει.
Φυσούνες είκοσι φυσούν στες κάψες τους και βγάζουν
ευκολοφύσητην πνοήν σφοδρήν ή μετρημένην,
πότε με βία πότε σιγά να υπηρετούν, ως θέλει
ο Ήφαιστος, ώστ' εύκολα το έργο να τελειώσει.

c) The construction details of the shield (1474-481):

Σκληρόν χαλκόν, κασσίτερον, πολύτιμο χρυσάφι
και ασήμι βάζει στη φωτιά, κατόπιν μέγ' αμόνι
εις τον κορμόν τοποθετεί και στο δεξί του χέρι
σφύραν αδρανεί δυνατήν και το διλάβι στ' άλλο.
Κι έπλασε πρώτα δυνατήν ασπίδα και μεγάλην
όλην με τέχνην και τριπλόν λαμπρόν τριγύρω κύκλον
με πέντε διπλές έγινεν η ασπίδα και σ' εκείνην
λογιών εικόνες έπλαθε με την σοφήν του γνώσιν.

d) The behavior of the shield in the duel with Aeneas {Υ 261-272):

Κι από το σώμα του μακράν την κράτησε ο Πηλείδης
φοβούμενος μην εύκολα τη σπάσει πέρα ως πέρα
του Αινείου το μακρόσκιον κοντάρι του ανδρειωμένου.
Και δεν εννόησε ο μωρός ότι τα δοξασμένα
των θεών δώρ' από θνητούς ευκόλως δεν νικούνται,
μηδέ ποσώς υποχωρούν και τότε την ασπίδα
δεν έσπασε το δυνατό κοντάρι του ανδρειωμένου.
Ότι την φύλαξε ο χρυσός, δώρο του Ηφαίστου θείον,
δύο δίπλες εδιαπέρασεν και τρεις ήσαν ακόμη,
τι πέντε δίπλες ο χωλός τεχνίτης είχε στρώσει,
δύο χάλκινες και μέσαθε του κασσιτέρου δύο,
μιαν χρυσήν, που κράτησε το φράξινο κοντάρι.

e) The behavior of the shield in the duel with Asteropeos (Φ 161-164):

Εις τες φοβέρες σήκωσεν ο θείος Αχιλλέας
την λόγχην και τες δύο του ο Αστεροπαίος ήρως,
Ότι του ερχόταν βολικά και με τα δύο του χέρια.
Με την μιαν λόγχη κτύπησε τον κύκλον της ασπίδος,
αλλά την κράτησε ο χρυσός, το δώρημα το θείο.

As it turns out, the shield consists of two outer plates of hard bronze (tin brass), two tin plates and a central plate of (soft) gold. In other words, these are materials with very different -mechanical and other- properties, a fact that allows the propagation of the perforation to be inhibited within the shield materials. This "obstruction" of the piercing is achieved mainly through the absorption of the impact energy of the spear, from the plastic deformation of the central plate from gold!

The shield of Aiada

In the Iliad there are the following descriptions of the shield of Ajax of Telamonius from his duel with Hector (H 219-232, 244-248, 258-267):

Και ο Αίας επροχώρησε μ' ασπίδα ωσάν πύργον, \ χάλκινην μ' επτά δέρματα, που του έκαμε ο Τυχίος \ των σκυτοτόμων έξοχος, εγκάτοικος στην Ύλην, \ λαμπρήν την ετεχνούργησεν εφτά-διπλην με δέρμα \ δυνατών ταύρων, κι έβαλεν δίπλαν χαλκού ογδόην. \ Αυτήν στα στήθη επρόβαλεν ο Τελαμώνιος Αίας. \ Κι εστάθη εμπρός στον Έκτορα και τούπε με φοβέρες: \ «Ω Έκτωρ, θα γνωρίσεις συ, μόνος με μόνον τώρα, \ αν άλλοι εδώ των Δαναών ευρίσκονται ανδρειωμένοι, \ έξω από τον λεοντόκαρδον Πηλείδην ανδροφόνον, \ Αλλ' αυτός μένει στα κυρτά θαλασσοπόρο πλοία, \ Αφού στον πρώτον αρχηγόν Ατρείδην εχολώθη. \ Αλλ' εμείς είμεθ' αρκετοί με σε να μετρηθούμε \ Και πάμπολλοι, αλλ' άρχισε πρώτος εσύ την μάχην».

[ο Έκτορας]
είπε και το μακρόσκιον ετίναξε κοντάρι. \ Και την φρικτήν του Αίαντος εκτύπησεν ασπίδα \ Και τον χαλκόν που όγδοος επτά σκεπάζει δίπλες. \Τες έξι δίπλες έσχισε κι εστάθη στην εβδόμην \ Της λόγχης ο σκληρός χαλκός...
και ο Έκτωρ πρώτος έκρουσε στηνμέσην την ασπίδα, \ και η λόγχη δεν την έσπασε, ώστ' εκυρτώθ' η άκρη \ τότε πηδώντας έμπηξε την λόγχην στην ασπίδα \ του Έκτορος και απ' την ορμήν τον έκοφεν ο Αίας, \ και τονλαιμόν του λάβωσε η λόγχη κι έσταξ' αίμα. \ Και όμως ο Έκτωρ μ' όλ' αυτά την μάχην δεν αφήνει. \ Τραβιέται οπίσω κι απ' την γην με το τρανό του χέρι \ Πέτραν σηκώνει ολόμαυρην, μεγάλην και τραχείαν \ Του Αίαντος την φοβερήν επτάδιπλην ασπίδα \ Μ' αυτήν κτυπά στον ομφαλόν κι εβρόντησε ο χαλκός της.

The shield of Aiada is described as consisting of seven successive layers of cow-leather and an eighth exterior of hard brass. It also mentions its maker, Tychios from Ili, who was a famous leather craftsman.

In this case, the mechanism of operation of the shield is based on friction. During the impact of the spear, the shield is deformed and the friction between the layers of the skin absorbs the energy of the impact. This presupposes the existence of a sufficient number of layers and, as it turned out, the seven layers constitute the minimum (and ideal) number, which makes the shield invulnerable under the given conditions (Fig. 3). This fact, which also fully confirms the Homeric descriptions, is verified by the present results both numerically and experimentally based on the models of the previous case.

In addition to arithmetic, an experimental study was performed, during which the shield models were constructed and tested in perforation, with the help of an air weapon (Fig. 5), whose projectile contained as much energy as the spear, as mentioned above. Various combinations of number and thickness of layers were tested, with the overall thickness of the shield remaining constant. It was absolutely confirmed that the number of seven layers is necessary for the non-piercing of the shield and also the accuracy of the Homeric description that the last (eighth) layer of the skin held the spear.

Conclusions

The up-to-date verification of the (extremely detailed) descriptions of the Iliad about the construction and behavior in the battle of the shields of Achilles and Aiada of Telamonius is an extremely important event in the area of ​​so-called experimental archeology. It turns out that the Greeks of that time possessed technological knowledge extremely advanced even by today's standards.
Of course, there is no evidence of scientific knowledge to support these technological possibilities, but questions still arise that can hardly be ignored. Especially in view of the way in which these descriptions have reached our days, that is, orally (at least until the invention of writing) from generation to generation, but without losing their accuracy and reliability. So the existence of a wonderful world, not only full of harmony and beauty but also technologically advanced to an astonishing degree, is not a product of fantasy or poetic inspiration, but it seems to have been a completely tangible reality.