While I do not under seigecraft, I understand some of the words in a different context. Maybe it will help in throwing light to the actual design and use of the weapon.
Words in sanskrit do not have a fixed meaning, they are attributes, So a single object can have multiple names for each of its attribute, and a single name can be used for multiple objects, Some context is necessary to understand which object is being spoken about. sthirayantrám Is stationary Machine,It need not be immovable, it might only need to be stationary during operation, Sarvatobhadra: Sarvato=Everywhere, Bhadra has multiple meaning, it could be bull elephant, Iron, fir tree, auspicious. I think it means covered by iron on all side. jamadagnya: Son Of Jamadagni(All consuming fire), i.e. Parshuram (Parshu=Axe) bahumukha: Many-Face visvásagháti: Betrayer, Vishwas=Confidence, Ghataka=Deadly(Attack) yánaka: Vehicle parjanyaka: Leader of the citizens Ardha: Half. Urdhava: Erect/Vertical
The second set of weapons are those that are carried by soldiers, Pánchálika: Another name for draupadi (ref: Mahabharatha). Daughter of Panchal( Panchal is The name of an ancient king and also the name of his kingdom.) Also mean's 5. Also a class of poisonous insects... Since Chanakya spoke of poison(Vishakanya) this could mean, A poisoned weapon. Devadanda: God's Stick musala: Mace (Crusher?) Yashti: Stick/staff/pole hastiváraka: Elephant Restrainer
tálavrinta:?? mudgara: Hammer Gadha: Mace
kuddála: Digger( Spade?) Chakra is a throwing disk with serrated edges. Trishula is trident sataghni: 100 Fire, Cannon/Artillery