Fatigue Performance Evaluations of Vehicle Toroidal Liquefied Petroleum Gas Fuel Tanks

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Fuat Kartal ◽  
Yasin Kisioglu
Keyword(s):  
Fatigue Life ◽  
Three Dimensional ◽  
Nonlinear Material ◽  
Experimental Investigations ◽  
Geometrical Parameters ◽  
Liquefied Petroleum Gas ◽  
Element Analysis ◽  
Pressure Load ◽  
Fea Modeling ◽  
Fuel Tanks

In this study, fatigue performances of the vehicle toroidal liquefied petroleum gas (LPG) fuel tanks were examined to estimate the fatigue life and its failure locations using both experimental and finite element analysis (FEA) methods. The experimental investigations performed as accelerated fatigue tests were carried out using a hydraulics test unit in which the tanks were internally pressurized by hydraulic oil. The LPG tanks were subjected to repeated cyclic pressure load varying from zero to service pressure (SP) of the tank. The computerized FEA modeling of these tanks were developed in three-dimensional (3D) form using nonuniform geometrical parameters and nonlinear material properties. These models were also subjected to zero-based high cycle fatigue pressure load considering the stress life approach. The FEA modeling process was also simulated in nonhomogeneous material conditions. Therefore, the fatigue life performance and failure location of the toroidal LPG fuel tanks were predicted using the computer-aided simulations and compared with the experimental results.

Burst Pressure Determination of Vehicle Toroidal Oval Cross-Section LPG Fuel Tanks

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Yasin Kisioglu
Keyword(s):  
Nonlinear Models ◽  
Weld Zone ◽  
Modeling Processes ◽  
Liquefied Petroleum Gas ◽  
Element Analysis ◽  
Fea Modeling ◽  
Fuel Tanks ◽  
Oval Cross Section ◽  
Thickness Variations

This study addresses the prediction of the burst pressures and burst failure locations of the vehicle toroidal liquefied petroleum gas (LPG) fuel tanks using both experimental and finite element analysis (FEA) approaches. The experimental burst test investigations were carried out hydrostatically in which the cylinders were internally pressurized with water. The FEA modeling processes of these LPG fuel tanks subjected to incremental internal uniform pressure were performed in the nonlinear field. Two different types of nonlinear models, plane and shell, were developed and evaluated under nonuniform and axisysmmetric boundary conditions. The required actual shell properties including weld zone and shell thickness variations were also investigated and used in the computerized modeling processes. Therefore, the results of the burst pressures and their failure locations were predicted and compared with experimental ones.

Effect of Residual Stress or Plastic Deformation History on Fatigue Life Simulation of Pipeline Dents

2018 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Rick Wang
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain History ◽  
Deformation History ◽  
Stress Strain ◽  
Element Analysis ◽  
Fea Model

Mechanical dents often occur in transmission pipelines, and are recognized as one of major threats to pipeline integrity because of the potential fatigue failure due to cyclic pressures. With matured in-line-inspection (ILI) technology, mechanical dents can be identified from the ILI runs. Based on ILI measured dent profiles, finite element analysis (FEA) is commonly used to simulate stresses and strains in a dent, and to predict fatigue life of the dented pipeline. However, the dent profile defined by ILI data is a purely geometric shape without residual stresses nor plastic deformation history, and is different from its actual dent that contains residual stresses/strains due to dent creation and re-rounding. As a result, the FEA results of an ILI dent may not represent those of the actual dent, and may lead to inaccurate or incorrect results. To investigate the effect of residual stress or plastic deformation history on mechanics responses and fatigue life of an actual dent, three dent models are considered in this paper: (a) a true dent with residual stresses and dent formation history, (b) a purely geometric dent having the true dent profile with all stress/strain history removed from it, and (c) a purely geometric dent having an ILI defined dent profile with all stress/strain history removed from it. Using a three-dimensional FEA model, those three dents are simulated in the elastic-plastic conditions. The FEA results showed that the two geometric dents determine significantly different stresses and strains in comparison to those in the true dent, and overpredict the fatigue life or burst pressure of the true dent. On this basis, suggestions are made on how to use the ILI data to predict the dent fatigue life.

Formulation of Three-Dimensional Green’s Function and its Application to Fatigue Life Evaluation of Pressurizer

2006 ◽  
Vol 324-325 ◽  
pp. 387-390
Author(s):  
Yoon Suk Chang ◽  
Shin Beom Choi ◽  
Jae Boong Choi ◽  
Young Jin Kim ◽  
Myung Jo Jhung ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Green’S Function ◽  
Green's Function ◽  
Three Dimensional ◽  
Stress Transfer ◽  
Life Assessment ◽  
Element Analysis ◽  
Fatigue Evaluation ◽  
Effective Assessment

Major nuclear components have been designed by conservative codes to prevent unanticipated fatigue failure. However, more realistic and effective assessment is necessary in proof of continued operation beyond the design life. In the present paper, three-dimensional stress and fatigue evaluation is carried out for pressurizer employing complex full geometry itself instead of conventional discrete subcomponents. For this purpose, temperature and mechanical stress transfer Green’s functions are derived from finite element analyses and applied to critical locations of pressurizer. In accordance with comparison of resulting stresses obtained from the Green’s function and detailed finite element analysis, suitability of the specific Green’s function is investigated. Finally, prototype of fatigue life assessment results is provided along with relevant ongoing activities.

Progressive fatigue behavior of single-lap bolted laminates under different tightening torque magnitudes

2020 ◽  
Vol 234 (10) ◽  
pp. 1303-1312
Author(s):  
M Feyzi ◽  
S Hassanifard ◽  
A Varvani-Farahani
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Behavior ◽  
Damage Model ◽  
Three Dimensional ◽  
Bolted Joints ◽  
Element Analysis ◽  
Damage And Failure ◽  
Experienced Fatigue ◽  
Three Dimensional Finite Element

The present paper studies fatigue damage and life of single-lap bolted joints tightened with different torque magnitudes subjected to uniaxial load cycles. The adherends were constructed from E-glass/epoxy layers using a hand layup technique and assembled by 1.5, 3, and 8 N m of applied torques. Increasing the torque magnitude benefitted the final fatigue life of the joints so that the high-cycle fatigue life of the joint sample tightened with 8 N m was as high as 10 times that of the joint tightened with 1.5 N m. In the numerical section of this study, a three-dimensional finite element analysis was employed, and the impacts of applied torques were included in the progressive damage model to assess damage and failure in the bolted joints. For the joints tightened with higher torque levels, numerical results revealed higher fatigue lives but at the cost of more delamination at the vicinity of the hole. Laminate fracture surface was investigated through scanning electron microscopy and more cracking/damage progress was evidenced in matrix, fiber, and matrix–fiber interface as composite joints experienced fatigue cycles. Experimental life data of tested joints agreed with those anticipated through the use of finite element analyses indicating the developed model as an appropriate tool in evaluating the effects of applied torques on the fatigue fracture behavior of bolted laminates.

Design Optimization of Snap-Fit Integral Parts by FEA and Statistical Analysis

2006 ◽  
Author(s):  
L. Goteti ◽  
J. Choi ◽  
J. Park
Keyword(s):  
Three Dimensional ◽  
Statistical Technique ◽  
Considerable Effect ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Geometrical Features ◽  
Length Width ◽  
Integral Attachment ◽  
Plastic Parts

Snap-fit integral attachments are used widely for joining plastic parts. The proliferated use of integral attachment in the form of snap-fit features in designs is due to the ability to mould such parts of great complexity at little cost. The exceptional diversity of part geometry and integral snap-fit features has made it seem that design possibilities may be unlimited. Thus, attempts at optimization might be intractable. A design of experiments (DOE) approach coupled with three-dimensional, geometrical non-linear finite element analysis (FEA) was used to calculate the insertion and retention responses on such parts for various geometrical parameters like length, width and angles. A statistical technique was employed to formulate empirical relationships among the geometrical dimensions, to investigate the effect of these parameters on the design as well as to obtain optimal insertion and retention forces or strains. Design equations obtained from this methodology were verified within the DOE domain and it was observed that the predicted responses were ranged within 30% of the FEA results. During this investigation, it was observed that geometrical features of a block, which exert force on the snap-fit features, have a considerable effect on the results. Therefore, the effects of the block parameters on the various responses were also studied. An attempt was also made to understand the effect of the block parameters such as corner radius and thickness on the design formula, which depicts the geometrical parameters of the snap-fit part as a function of insertion and retention forces. It is expected that the results help to find optimal design parameters in order to enhance the performance of such snap-fit features.

Optimization of Adhesively Bonded Spar-Wingskin Joints of Laminated FRP Composites Subjected to Pull-Off Load: A Critical Review

2020 ◽  
Vol 8 (1) ◽  
pp. 29-46
Author(s):  
S. Rakshe ◽  
S. V. Nimje ◽  
S. K. Panigrahi
Keyword(s):  
Three Dimensional ◽  
Von Mises Stress ◽  
Geometrical Parameters ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Frp Composites ◽  
Dimensional Finite Element ◽  
Materials Used ◽  
Von Mises ◽  
Three Dimensional Finite Element

A review on optimization of adhesively bonded spar-wingskin joint (SWJ) of laminated fiber reinforced polymer (FRP) composites subjected to pull-off load is presented in this article using three-dimensional finite element analysis. Von Mises stress components have been computed across the width of joint at different interfaces viz. load coupler-spar, and load coupler-wingskin interfaces. Further, the weight of SWJ structure is considered as the objective function which needs to be minimized for optimization. In the first step, the material and lamination scheme of the FRP composite materials used for SWJ are optimized, and, in the second step, the geometrical parameters have been optimized on the basis of minimum von Mises stress and weight. Further, the effects of the material, lamination scheme, and geometrical parameters on the von Mises stress and weight have been validated using the Analysis of Variance (ANOVA) approach as prescribed by the Taguchi method. The results show that the material and spar thickness are the most significant factors influencing von Mises stress. The weight analysis reveals that there is a significant effect of change in material and wingskin thickness on SWJ performance. Suitable design recommendations have been made for SWJ in terms of material, lamination scheme and geometrical parameters.

Three-Dimensional Creep Analysis of Solder Joints in Surface Mount Devices

1995 ◽  
Vol 117 (1) ◽  
pp. 20-25 ◽  
Author(s):  
Pardeep K. Bhatti ◽  
Klaus Gschwend ◽  
Abel Y. Kwang ◽  
Ahmer R. Syed
Keyword(s):  
High Performance ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Nonlinear Material ◽  
Computational Time ◽  
Nonlinear Creep ◽  
Element Analysis ◽  
Surface Mount ◽  
Creep Analysis ◽  
Highly Nonlinear

Three-dimensional finite element analysis has been applied for determining time-dependent solder joint response of leaded surface mount components under thermal cycling. Two main challenges are the geometric complexity in mesh development and computationally intensive analysis because of the highly nonlinear material properties. Advanced techniques have been applied, including multi-point constraints for mesh transition, which reduces the number of degrees of freedom in the model, and substructuring, which effectively reduces computational time in the iterative analysis. The result is a generic approach for nonlinear creep analysis using commercial FEA software on a high performance workstation. Illustrations are provided for J and gullwing leaded packages.

Fatigue Life Evaluation of Vehicle Wheel Bolts under Random Loading

2005 ◽  
Vol 297-300 ◽  
pp. 1770-1775 ◽  
Author(s):  
Young Woo Choi ◽  
Byeong Wook Noh ◽  
Kyung Chun Ham ◽  
Sung In Bae
Keyword(s):  
Fatigue Life ◽  
Residual Life ◽  
Three Dimensional ◽  
Real Life ◽  
Local Stress ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Random Loading ◽  
Element Analysis ◽  
Three Dimensional Finite Element

The fatigue life of hexagon head and socket head bolts, attached to vehicle a wheel, is assessed and the estimation of the residual life of existing bolts in vehicle wheel is investigated. Field- measured load histories were applied in this test. Tensile tests and fatigue tests were performed to evaluate the effect of tightening torque and to obtain the basic experimental data. A three-dimensional finite element analysis was also performed to evaluate the local stress fields. Miner’s rule was used to predict the fatigue life of bolts. The results indicate the prediction of fatigue life of the bolts was in good agreement with the real life of vehicle wheel bolts in this test.

Development of a Three-Dimensional Green’s Function and Its Application to the Fatigue Evaluation of Reactor Pressure Vessel

2006 ◽  
Author(s):  
M. Y. Ahn ◽  
J. C. Kim ◽  
Y. S. Chang ◽  
J. B. Choi ◽  
Y. J. Kim ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Green’S Function ◽  
Green's Function ◽  
Pressure Vessel ◽  
Three Dimensional ◽  
Reactor Pressure Vessel ◽  
Element Analysis ◽  
Reactor Pressure

The design of major nuclear components for the prevention of fatigue failure has been achieved on the basis of ASME codes, which are usually very conservative. However, it is necessary to make it more accurate for the continued operation beyond the design life. In this paper, 3-dimensional stress and fatigue analyses reflecting entire geometry have been carried out. The number of operating transient data obtained from a monitoring system were filtered and analyzed. Then, Green’s function which transfers temperature gradient into the corresponding thermal stress is proposed and applied to critical locations of a reactor pressure vessel. The validity of proposed Green’s function is approved by comparing the result with corresponding 3-D finite element analysis results. Also, the amount of conservatism included in design transients in comparison with real transients is analyzed. The results for 3-D finite element analysis are also compared with corresponding 2-D finite element analysis results, and a considerable amount of difference was observed in terms of fatigue life. Therefore, it is expected that the proposed evaluation scheme adopting real operating data and Green’s function can provide more accurate fatigue life evaluation for a reactor pressure vessel.

Effect of Intermetallic Compounds on the Thermomechanical Fatigue Life of Three-Dimensional Integrated Circuit Package Microsolder Bumps: Finite Element Analysis and Study

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Soud Farhan Choudhury ◽  
Leila Ladani
Keyword(s):  
Fatigue Life ◽  
Integrated Circuits ◽  
Integrated Circuit ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Strain Range ◽  
Bulk Solder ◽  
Element Analysis ◽  
Plastic Strain Range ◽  
Inelastic Strains

Currently, intermetallics (IMCs) in the solder joint are getting much attention due to their higher volume fraction in the smaller thickness interconnects. They possess different mechanical properties compared to bulk solder. Large volume fraction of IMCs may affect the mechanical behavior, thermomechanical and mechanical fatigue life and reliability of the solder interconnects due to very brittle nature compared to solder material. The question that this study is seeking to answer is how degrading IMCs are to the thermomechanical reliability of the microbumps used in three-dimensional (3D) integrated circuits (ICs) where the microsolder bumps have only a few microns of bond thicknesses. Several factors such as “squeezed out” solder geometry and IMC thickness are studied through a numerical experiment. Fatigue life is calculated using Coffin–Manson model. Results show that, though undesirable because of high likelihood of creating short circuits, squeezed out solder accumulates less inelastic strains under thermomechanical cyclic load and has higher fatigue life. The results show that with the increase of IMCs thickness in each model, the inelastic strains accumulation per cycle increases, thus decreasing the fatigue life. The drop in fatigue life tends to follow an exponential decay path. On the other hand, it was observed that plastic strain range per cycle tends to develop rapidly in Cu region with the increase in IMC thickness which calls for a consideration of Cu fatigue life more closely when the microbump contains a higher volume fraction of the IMCs. Overall, by analyzing the results, it is obvious that the presence of IMCs must be considered for microsolder bump with smaller bond thickness in fatigue life prediction model to generate more reasonable and correct results.

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