scholarly journals Effect of Periphery Fixity on Ballistic Limit of Thin Aluminum Plate Subjected to Blunt and Ogival Projectile Impact

2014 ◽  
Vol 19 (2) ◽  
pp. 379-395
Author(s):  
G. Tiwari ◽  
M.A. Iqbal ◽  
P.K. Gupta

Abstract Three-dimensional numerical simulations were carried out with the ABAQUS/explicit finite element code to study the influence of target boundary conditions on its ballistic limit. 1mm thick 1100-H12 aluminum target of 255 mm span diameter was hit by 19 mm diameter and 50.8 mm length blunt nosed projectile. The mass of the projectile was kept as 52.5 gm. The boundary condition effects on the ballistic limit were investigated by varying the target periphery boundary condition as fully clamped and partially clamped target (75%, 50% and 25%) subjected to projectile impact. The energy absorption and ballistic limit of the target was found to be significantly affected by the boundary conditions. Some of the finite element analysis results were compared with experimental and numerical results reported in international literature and a good agreement between the two was found.

Author(s):  
Y B Park ◽  
D Y Yang

In metal forming, there are problems with recurrent geometric characteristics without explicitly prescribed boundary conditions. In such problems, so-called recurrent boundary conditions must be introduced. In this paper, as a practical application of the proposed method, the precision cold forging of a helical gear (which is industrially useful and geometrically complicated) has been simulated by a three-dimensional rigid-plastic finite element method and compared with the experiment. The application of recurrent boundary conditions to helical gear forging analysis is proved to be effective and valid. The three-dimensional deformed pattern by the finite element analysis is shown, and the forging load is compared with the experimental load. The profiles of the free surface of the workpiece show good agreement between the computation and the experiment.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.


2017 ◽  
Vol 7 ◽  
pp. 219-223
Author(s):  
Beril Demir Karamanli ◽  
Hülya Kılıçoğlu ◽  
Armagan Fatih Karamanli

Aims The aim of this study is to evaluate the effects of the chincup appliance used in the treatment of Class III malocclusions, not only on the mandible or temporomandibular joint (TMJ) but also on all the craniofacial structures. Materials and Methods Chincup simulation was performed on a three-dimensional finite element (FE) model. 1000 g (500 g per side) force was applied in the direction of chin-condyle head. Nonlinear FE analysis was used as the numerical analysis method. Results By the application of chincup, stresses were distributed not only on TMJ or mandible but also on the circummaxillary sutures and other craniofacial structures. Conclusions Clinical changes obtained by chincup treatment in Class III malocclusions are not limited by only mandible. It was seen that also further structures were affected.


2012 ◽  
Vol 562-564 ◽  
pp. 1943-1946
Author(s):  
Yong Hu ◽  
Jin Gan Song ◽  
Qing Zou ◽  
Ke Zhu ◽  
Xiao Long Wang

Because both of the volume and the weight of the photoelectric platform are small, the structure of two frames and two axes is used in the photoelectric platform. As the key component of the photoelectric platform, the main frame should have sufficient strength and rigidity. In order to achieve this object, three-dimensional entity model of the main frame is established using CATIA software. Then the finite-element analysis of the model is finished with ANSYS Workbench. Based on the analysis results, the weak links of the main frame is found. Then these links are improved and the main frame is analyzed again. After improving the structure, the results of the finite-element analysis show that the main frame meets the requirements of design and has perfect overall performance.


1981 ◽  
Vol 103 (4) ◽  
pp. 385-391 ◽  
Author(s):  
B. S. Thompson

Variational theorems are presented for analyzing the vibrational response of flexible linkage mechanisms and the surrounding acoustic medium in which they are immersed. These theorems are established by generalizing Hamilton’s principle through using Lagrange multipliers to incorporate field equations and boundary conditions within the functional. The same philosophy is adopted to handle the conditions at the fluid-structural interface. When independent arbitrary variations of the system parameters are permitted, these acousto-elastodynamic theorems yield as characteristic equations the equation of motion for each member of the linkage, the acoustical wave equation, the compatibility conditions at the interface between the fluid and solid continua, and also the boundary conditions. These variational statements provide the foundations for several different classes of finite element analysis.


Author(s):  
Marcus Gamino ◽  
Samuel Abankwa ◽  
Raresh Pascali

A general assumption in performing vortex-induced vibration (VIV) analysis of pipeline free spans is both ends of the free span are fixed and/or pinned in order to simplify computational simulations; however, DNV Recommended Practice F105 states that these boundary conditions must adequately represent the pipe-soil interaction and the continuality of the pipeline. A computational methodology is developed to determine the effects of pip-soil interaction at the ends of a free span. Three-dimensional fluid-structure interaction (FSI) simulations are performed by coupling the computational fluid dynamics (CFD) codes from STAR-CCM+ with the finite element analysis (FEA) codes from ABAQUS. These FSI simulations in combination with separate coupled Eulerian-Lagrangian (CEL) simulations are modeled to mimic real word conditions by setting up boundary conditions to factor in the effects of pipe-soil interaction at the ends of the span. These simulations show a mitigation of overall stresses to the free spans; as a result, the integration of pipe-soil interaction in free span assessment may prove cost effective in the prevention of unnecessary corrective action.


2014 ◽  
Vol 614 ◽  
pp. 576-579
Author(s):  
Xiu Hua Ma

In this paper, SolidWorks2012 was redeveloped by visual programming tool Visual Basic6.0 to realize the three-dimensional parametric design of wellhead gate valve and the transformation of corresponding engineering drawings on the engineering diagram template. Then the finite element analysis was progressed directly by using the SolidWorks module of the finite element analysis. This can shorten design time of gate valve and improve work efficiency.


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