Effects of Configuration on Plastic Package Stresses

1991 ◽  
Vol 113 (4) ◽  
pp. 397-404 ◽  
Author(s):  
L. T. Nguyen ◽  
S. A. Gee ◽  
W. F. v. d. Bogert
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Stress Reduction ◽  
Stress Profile ◽  
Strain Gages ◽  
Molding Compounds ◽  
Compressive Stresses ◽  
Plastic Packages ◽  
Plastic Package ◽  
Element Simulation

This paper examines the effects of device and leadframe configurations on the stresses encountered in typical Dual-in-Line plastic packages. The parameters studied include the die size, the die pad size, the location of the die with respect to the die pad center, and the die coating configuration. Special piezoresistive strain gages deposited on dies of varying sizes are used to map the stress profile across the die surfaces after molding. Finite element simulation of these effects is also conducted. Results indicate that the compressive stresses from the molding compounds are governed with diminishing influence by the size of the die. Furthermore, rather high compressive stresses are observed in the vicinity of the edges of large dies. More subtle effects are found for the influence of the die pad size, the aspect ratio of the die, and the extent of the die offsetting with respect to the die pad center. Finally, by surrounding the die with a thin trail of silicone gel to provide for lateral cushioning, stress reduction is slightly more effective than in the standard “glob-top” coating.

Investigation on endurance evaluation of a portal crane: experimental, theoretical and finite element analysis

2020 ◽  
Vol 62 (4) ◽  
pp. 357-364
Author(s):  
Yusuf Aytaç Onur ◽  
Hakan Gelen
Keyword(s):  
Finite Element ◽  
Critical Points ◽  
Maximum Stress ◽  
Strain Gages ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Element Simulation ◽  
Main Girder ◽  
Stressed Component ◽  
Portal Crane

Abstract In this study, the stress on portal crane components at various payloads has been investigated theoretically, numerically and experimentally. The portal crane was computer-aided modeled and finite element analyses were performed so that the most stressed points at the each trolley position investigated on the main girder could be determined. In addition, the critical points were marked on the portal crane, and strain gages were attached to the those critical points so that stress values could be experimentally determined. The safety factor values at different payloads were determined by using finite element simulation. Results indicate that the most stressed component in the examined portal crane is the main girder. Experimental results indicate that the maximum stress value on the main girder is 3.05 times greater than the support legs and 8.99 times larger than the rail.

Superplastic Forming Formula for Aluminum Channel Panels

2005 ◽  
Author(s):  
Frank G. Lee ◽  
M. David Hanna
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Superplastic Forming ◽  
Forming Process ◽  
Taguchi Design Of Experiment ◽  
Forming Parameters ◽  
Physical Experiments ◽  
Element Simulation ◽  
Experiment Method ◽  
Sectional Analysis

A parametric study was conducted to determine how the design features and forming parameters affect part thinning and forming time in the Superplastic Forming Process (SPF). Explicit formulas, describing the maximum percent thinning and the forming time for channel parts formed by the SPF process as a function of eight designs and forming parameters, were derived. The formulas are good approximations of those obtained by finite element simulation analyses and physical experiments. Thinning of the channels was influenced most by the component aspect ratio (height versus width) and entry radius at top of the channel forming tool. The forming time was most influenced by strain rate, aspect ratio and tool bottom radius. A design domain can be established to avoid excessive thinning. The Taguchi design-of-experiment method was applied to select parameter combinations, and the MARC finite element code was used to conduct sectional analysis for various combinations.

Finite Element Stress Analysis for Leak Tests of Pipe Flange Connections Subject to Internal Pressure and Bending Moment

2011 ◽  
Author(s):  
Satoshi Nagata ◽  
Toshiyuki Sawa ◽  
Takashi Kobayashi ◽  
Hirokazu Tsuji
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Bending Moment ◽  
Strain Gages ◽  
Element Analysis ◽  
Element Simulation ◽  
Sealing Performance ◽  
Gas Leak ◽  
Helium Gas

This paper reports the results of finite element analysis representing the sealing performance tests on the slip-on type pipe flange connections for 8 inch and 16 inch. The flange connections are subjected to internal pressure and bending moment. Internal pressure is applied by helium gas and the bending moment is loaded through 4 points bending equipment. Gas leak rates are measured by pressure decay method. During the test, the variations in the axial bolt force are monitored for all the bolts by strain gages. The pipe stress at the junction of pipe and flange is also measured. Finite element analysis simulates the tests and the simulated results are compared with the measured data. Then the behaviors of the slip-on type flange connections under internal pressure and bending moment as well as the sealing performance are clarified by the experiment and the finite element simulation.

Further Studies to Evaluate Crack Opening Areas for Through-Wall Cracks in the Vicinity of Welded Attachments

2010 ◽  
Author(s):  
J. K. Sharples ◽  
C. J. Madew ◽  
R. Charles ◽  
P. J. Budden
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Complex Geometry ◽  
Crack Opening ◽  
Stress Profile ◽  
Finite Element Models ◽  
Compressive Stresses ◽  
Displacement Theory ◽  
Plate Geometry

A paper was presented at the 2009 ASME PVP Conference on evaluating, by finite element techniques, crack opening area (COA) and stress intensity factor, KI, values for through-wall cracks located in the region where an attachment is welded to a plate geometry. Both membrane and bend loads were considered. In addition, based on the stress profile in the un-cracked complex geometry over the region where the cracks would be introduced, COA and KI values were evaluated for the same crack sizes located in a simple plate geometry. This enabled information to be established on the conservatism, or otherwise, of using simple plate solutions to evaluate COA and KI for cracks in the complex geometry. The present paper reports on further studies that have been undertaken to investigate the effect on the previous COA and KI results of considering (i) large displacement theory which may be important for combined membrane and bend loading, and (ii) contact elements in the finite element models since in the previous studies, the mesh was allowed to “overlap on itself” when crack closure was evident due to compressive stresses during bend loading.

scholarly journals Finite element simulation of fracture in a restored premolar tooth using high aspect ratio elements

2018 ◽  
Vol 34 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Maryam Ramezani ◽  
Estevam Barbosa de Las Casas ◽  
Cláudia Machado de Almeida Mattos ◽  
Osvaldo Luís Manzoli ◽  
Eduardo Alexandre Rodrigues
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Finite Element Simulation ◽  
High Aspect Ratio ◽  
Element Simulation

Influence of Residual Stresses on the Interfacial Toughness Measurement by Cross-Sectional Nanoindentation

2007 ◽  
Vol 353-358 ◽  
pp. 400-403
Author(s):  
Pu Lin Nie ◽  
Yao Shen ◽  
Jie Yang ◽  
Qiu Long Chen ◽  
Xun Cai
Keyword(s):  
Thin Films ◽  
Finite Element ◽  
Residual Stresses ◽  
Interfacial Adhesion ◽  
Geometrical Parameters ◽  
Cross Sectional ◽  
Interfacial Toughness ◽  
Compressive Stresses ◽  
Element Simulation ◽  
Toughness Measurement

Cross-sectional nanoindentation (CSN) is a new method for measuring interface adhesion of thin films. The interfacial energy release rate (G), characterizing interfacial adhesion, is calculated from the material and geometrical parameters relevant to the test. Effects of residual stresses on G and crack tip phase angle Ψ, have been studied by finite element simulation in this study. The results show tensile residual stresses increase G and compressive stresses reduce it, and they have similar effects on the magnitude of Ψ.

scholarly journals Finite Element Simulation Study of Ultrasonic Vibration-Assisted Tensile High-Volume Fraction SiCp/Al Composite

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3841 ◽  
Author(s):  
Zhang ◽  
Xiang ◽  
Wu ◽  
Feng ◽  
Shi ◽  
...  
Keyword(s):  
Finite Element ◽  
Tensile Strength ◽  
Finite Element Simulation ◽  
Ultrasonic Vibration ◽  
Stress Reduction ◽  
Volume Fraction ◽  
Aluminum Matrix ◽  
High Volume ◽  
Experimental Results ◽  
Element Simulation

Silicon carbide particle-reinforced aluminum matrix composite (SiCp/Al) has been widely used in the military and aerospace industry due to its special performance; however, there remain many problems in the processing. The present paper introduces an ultrasonic vibration tensile apparatus and a composite tensile specimen and performs Abaqus finite element simulation on high-volume SiCp/Al. The results show that the stress-strain curve increases linearly during conventional tensile strength; the intermittent vibration tensile strength is similar to the full course vibration tensile strength: The magnitude of the stress reduction increases as the amplitude of the ultrasound increases and the vibration frequency increases. The tensile rate is inversely proportional to the magnitude of the stress reduction, and in the ultrasonic parameters, the amplitude has the greatest influence on the magnitude of the stress reduction, followed by the tensile rate; additionally, the frequency has the least influence on the magnitude of the stress reduction. The experimental results show that the simulation results are consistent with the experimental results.

Effects of Residual Stress on the Measurement of Hardness and Elastic Modulus using Nanoindentation

1994 ◽  
Vol 338 ◽  
Author(s):  
G.M. Pharr ◽  
T.Y. Tsui ◽  
A. Bolshakov ◽  
W.C. Oliver
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Finite Element Simulation ◽  
Linear Array ◽  
Point Of View ◽  
Hardness Testing ◽  
Standard Methods ◽  
Compressive Stresses ◽  
Element Simulation ◽  
Made In

ABSTRACTThe effects of stress on the measurement of hardness and elastic modulus in aluminum alloy 8009 have been studied experimentally and by finite element simulation. The experiments were performed by making a linear array of nanoindentations on the side of a stressed bend bar, sampling regions of high uniaxial tension, high uniaxial compression, and a variety of stresses in between. When analyzed according to standard methods, the nanoindentation data reveal a decrease in both hardness and modulus with increasing stress from compression to tension. While the decrease in hardness is consistent with previous observations made in conventional hardness testing, the modulus decrease was unexpected. Finite element simulation revealed that the drops in hardness and modulus are not real, but occur because the procedure for determining contact area from the nanoindentation load-displacement data does not account for pileup around the indentation. The finite element simulation shows that large compressive stresses promote pileup while tensile stresses reduce it, and this must be properly accounted for if accurate hardnesses and moduli are to be obtained. Experimental results are presented which further support this point of view.

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