Simulacija streljanja s fračo iz hiperelastičnega materiala

Bedić, Žiga (author), Brojan, Miha (mentor)

Cilj naloge je zasnovati preprosto simulacijo streljanja s fračo, ki odraža obnašanje frače in izstrelka med strelom. Frača ima dva rogla, elastična nit pa je narejena iz gumijastega materiala, ki ga je možno dobro opisati s hiperelastičnim materialnim modelom. Pred obravnavo gibanja izstrelka smo s pomočjo nateznega preizkusa določili potrebne materialne lastnosti elastične niti. Za teoretično analizo mehanske karakteristike elastike smo uporabili dva reološka hiperelastična modela materiala, Mooney-Rivlinovega in Neo-Hookeovega. S primerjavo teoretično dobljene krivulje z eksperimentalno smo določili materialne parametre elastike, s pomočjo katerih smo nato izračunali količino potencialne energije, ki se med napenjanjem frače shrani v njej. Ob predpostavki, da se vsa potencialna energija, shranjena v frači med strelom pretvori v kinetično energijo, smo izračunali izstrelitveno hitrost in nato preko preproste simulacije analizirali kakšen vpliv na gibanje izstrelka imajo izstrelitvena hitrost, naklonski kot izstrelitve in aerodinamični upor. Prišli smo do ugotovitve, da izbira hiperelastičnega materialnega modela vpliva na količino energije, ki se med napenjanjem shrani v frači, kar posledično vpliva na izstrelitveno hitrost in gibanje izstrelka.

• Language: Slovenian
• Keywords: hiperelastični material, potencialna energija, kinetična energija, natezni preizkus, aerodinamični upor
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [Ž. Bedić]
• Year: 2023
• Number of pages: XV, 28 str.
• PID: 20.500.12556/RUL-147290
• UDC: 539.31:620.172(043.2)
• COBISS.SI-ID: 157232899
• Publication date in RUL: 29.06.2023

BEDIĆ, Žiga, 2023, Simulacija streljanja s fračo iz hiperelastičnega materiala [online]. Bachelor’s thesis. Ljubljana : Ž. Bedić. [Accessed 11 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=147290

Secondary language

• Language: English
• Title: Simulation of shooting with a sling made of hyperelastic material

Abstract

The goal of the thesis assignment is to design a simple slingshot shooting simulation that reflects the behavior of the slingshot and projectile during the shot. The classic Y-shaped frame sling has the elastic tube/thread made of a rubber material that can be well described with a hyperelastic material model. Before considering the movement of the projectile, we determined the necessary material properties of the elastic thread with the help of a tensile testing. For the theoretical analysis of the mechanical characteristics of elastic, we used two rheological hyperelastic material models, Mooney-Rivlin and Neo-Hooke. By comparing the theoretically obtained curve with the experimental one, we determined the material parameters of the elastic, with the help of which we then calculated the amount of potential energy that is stored in it during pulling back the elastic of the slingshot. Assuming that during the shot all the potential energy stored in the slingshot is converted into kinetic energy, we calculated the launch speed/initial velocity of the projectile and then through a simple simulation analyzed the influence of the initial velocity, launch angle and aerodynamic resistance on the movement of the projectile. We have concluded that the choice of hyperelastic material model affects the amount of energy that is stored in the sling during tensioning, which in turn affects the launch speed and the movement of the projectile.

• Keywords: hyperelastic material, potential energy, kinetic energy, tensile testing, aerodynamic drag