Finite element modelling and analysis of recoil springs in automatic weapons

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Makina Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2013

Öğrenci: HAKAN ZALOĞLU

Eş Danışman: ENDER CİĞEROĞLU, GÖKHAN OSMAN ÖZGEN

Özet:

As a tool for weapon designers, a finite element based analysis methodology is developed for estimating the mechanical behavior of the recoil spring during a firing cycle. All models are developed in LS-DYNA to be used in analysis to estimate the nonlinear force deflection characteristics and dynamic stress in the spring during a representative firing cycle. An experimental study is also performed to validate the finite element based analysis methodology. Modeling, analysis approach and modeling parameters and their effects on the accuracy of force-deflection characteristics and stress responses are obtained from finite element based methodology. Moreover, those effects are investigated via various simulated scenarios and comparisons are made between the results of analysis and actual experiments replicating some of the analysis performed. Weapon designers should be able to estimate the spring parameters carefully in order to simulate the gun dynamics during the design phase. In addition, stress levels in the spring during the firing cycle should remain below the yield stress of the material. The designer sets the stiffness of the recoil spring by considering the rounds fired in unit time and also the desired recoil characteristics of the weapon to be designed. The recoil spring in a rifle is a long slender component, which is susceptible to buckling. Buckling behavior causes geometric nonlinearity in its deflection response. Therefore, the stiffness of the spring is really not a constant value, rather it is a relation that should be modeled as a function of deformation.