scholarly journals Impact Characteristics and Fatigue Life Analysis of Multi-Wire Recoil Spring for Guns

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Zhifang Wei ◽  
Xiaolian Zhang ◽  
Yecang Hu ◽  
Yangyang Cheng

Recoil spring is a key part in automatic or semi-automatic weapons re-entry mechanism. Because the stranded wire helical spring (SWHS) has longer fatigue life than an ordinary single-wire cylindrically helical spring, it is often used as a recoil spring in various weapons. Due to the lack of in-depth research on the dynamic characteristics of the current multi-wire recoil spring in recoil and re-entry processes, the fatigue life analysis of the current multi-wire recoil spring usually only considers uniform loading and does not consider dynamic impact loads, which cannot meet modern design requirements. Therefore, this paper proposes a research method for fatigue life prediction analysis of multi-wire recoil spring. Firstly, based on the secondary development of UG, a three-wire recoil spring parameterized model for a gun is established. Secondly, ABAQUS is used to carry out a finite element analysis of its dynamic response characteristics under impact, and experimental verification is performed. Then, based on the stress-time history curve of the dangerous position obtained by finite element analysis, the rain flow counting method is used to obtain the fatigue stress spectrum of recoil spring. Finally, according to the Miner fatigue cumulative damage theory, the fatigue life prediction of the recoil spring based on the S-N curve of the material is compared with experimental results. The research results show that the recoil spring has obvious transient characteristics during the impact of the bolt carrier. The impact velocity is far greater than the propagation speed of the stress wave in the recoil spring, which easily causes the spring coils to squeeze each other. The maximum stress occurs at the fixed end of the spring. And the mean fatigue curve (50% survival rate) is used to predict the life of the recoil spring. The calculation result is 8.6% different from the experiment value, which proves that the method has certain reliability.

Author(s):  
NN Subhash ◽  
Adathala Rajeev ◽  
Sreedharan Sujesh ◽  
CV Muraleedharan

Average age group of heart valve replacement in India and most of the Third World countries is below 30 years. Hence, the valve for such patients need to be designed to have a service life of 50 years or more which corresponds to 2000 million cycles of operation. The purpose of this study was to assess the structural performance of the TTK Chitra tilting disc heart valve model TC2 and thereby address its durability. The TC2 model tilting disc heart valves were assessed to evaluate the risks connected with potential structural failure modes. To be more specific, the studies covered the finite element analysis–based fatigue life prediction and accelerated durability testing of the tilting disc heart valves for nine different valve sizes. First, finite element analysis–based fatigue life prediction showed that all nine valve sizes were in the infinite life region. Second, accelerated durability test showed that all nine valve sizes remained functional for 400 million cycles under experimental conditions. The study ensures the continued function of TC2 model tilting disc heart valves over duration in excess of 50 years. The results imply that the TC2 model valve designs are structurally safe, reliable and durable.


Author(s):  
Recep M. Gorguluarslan ◽  
Seung-Kyum Choi

This research examines classification approaches for estimating the reliability of structural systems. To validate the accuracy and efficiency of the classification methods, a practical engineering problem; namely, a spider assembly of a washing machine, has been considered. For the spider assembly, fatigue life test, finite element analysis, physical experimentation, and a classification processes are conducted in order to establish the analytical certification of its current design. Specifically, the finite element analysis and fatigue life analysis are performed and their results are validated compared to physical experimental results. The classification process is developed to estimate the probability of failure of the spider assembly in terms of stress and fatigue life. The relationship between the random quantities and structural responses of the spider assembly is established using probabilistic neural network and the support vector machine classifiers. The performance margin of the spider assembly is fully identified based on the estimated failure probability and structural analysis results from the fatigue life analysis and classifications.


2019 ◽  
Vol 8 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Samuel O. Afolabi ◽  
Bankole I. Oladapo ◽  
Christianah O. Ijagbemi ◽  
Adeyinka O.M. Adeoye ◽  
Joseph F. Kayode

2018 ◽  
Vol 4 (4) ◽  
pp. 13
Author(s):  
Anand Mohan Singh ◽  
Megha Bhawsar ◽  
Neeraj Kumar Nagayach

In this present work a virtual environment has been created to investigate the failure analysis on spur gear assembly in which structural analysis, fatigue failure analysis and contact stress analysis have been performed using finite element method. For this work, a three dimensional cad model has been created and imported to ANSYS workbench for further finite element analysis. Various boundary conditions have been used to perform structural, fatigue failure assessment and contact analysis such as revolute joints is provided with Body Ground connection for 60 rpm for structure analysis, Augmented Lagrange method is set for contact analysis, for fatigue life analysis the fatigue strength factor is used as 0.85 for fully reverse loading and the life of shear stress in cycles and for the contact analysis linear and nonlinear contact are used for both source and target body. It has been observe that contact stress and bending stress not attain their maximum values at the same points, if the contact stress minimize in primary design stage then the failure of gear can minimized by analysis of the problem during the earlier stage of design. It can also be state that by using finite element analysis complex analysis like fatigue and contact analysis can be performed very accurately within a very short time and cost effectively rather than experimental analysis.


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