Finite Element Modeling of Large Turbine Generators; Calculations Versus Load Test Data

1981 ◽  
Vol PAS-100 (8) ◽  
pp. 3921-3929 ◽  
Author(s):  
J.W. Dougherty ◽  
S.H. Minnich
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Test Data ◽  
Load Test ◽  
Element Modeling ◽  
Turbine Generators

Airplane Tire Burst Plume Analysis

2005 ◽  
Author(s):  
Ryan Lee ◽  
Jon Gabrys
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Controlled Release ◽  
Finite Element Modeling ◽  
Short Duration ◽  
Test Data ◽  
Theoretical Calculations ◽  
Hole Diameter ◽  
Element Modeling ◽  
Rare Occasion

On rare occasion, aircraft tires have burst in flight after being retracted into the wheel well. The burst rapidly releases a high-pressure plume of gas that may cause damage to systems and structure mounted in the wheel well. Since airplanes must be designed to maintain continued safe flight and landing following a tire burst in the wheel well, it is essential that accurate definitions of the plume pressure loads be provided to the airplane structural and systems designers. Existing plume load definitions have been developed over the years from test data and theoretical calculations, but given the very short duration of the event and the complexity of the dynamics involved, it is desired to validate the existing threat definitions through the use of advanced finite element modeling. This paper describes the use of LS-DYNA to accurately predict the pressure plume created from the controlled release of a pressurized tank. This task is considered part of the validation phase. The next step will include the complexities of the deforming tire to quantify the effect of the rapidly changing hole diameter, and to study how the solution diverges from the classical prediction.

BGA Board Level Reliability Analysis & Optimization

2015 ◽  
Vol 2015 (DPC) ◽  
pp. 000958-000972
Author(s):  
Betty Yeung
Keyword(s):  
Finite Element ◽  
Solder Joint ◽  
Finite Element Modeling ◽  
Test Data ◽  
Cycle Time ◽  
Temperature Cycling ◽  
Reliability Test ◽  
Element Modeling ◽  
Simulation Procedure ◽  
Bga Package

The solder joint reliability of semiconductor package interconnects to printed circuit boards is critical for product durability. A dominant failure mode is solder fatigue due to the CTE mismatch between the BGA component and PCB at thermal cycling. However, it is well known that other factors can impact fatigue behavior and time to failure such as solder joint geometry, die geometry, solder system, etc. Finite element modeling (FEM) and simulation can play an integral role in providing deeper insight into the impact of these package parameters on the overall assembly. However, a major challenge of accurately modeling these systems includes simulation of multiple length scales from the package, substrate, and solder joints. The FEM approach addressing these can lead to reduced cycle time, accurate simulation, and improved package performance. In this work, the finite element modeling and simulation procedure is demonstrated for a BGA package at accelerated temperature cycling conditions. At the component level, key details regarding the properties and constituents of the BGA package mold compound and substrate are established by coupling measured experimental warpage data and finite element modeling. Comparison of simulated & Thermoire measurements shows excellent agreement at the package level, with warpage correlation achieved over the entire temperature range. At the assembly level, the truncated sphere model is used to arrive at precise solder joint profiles for accurate representation to tie the package to the board. The combined validated package-level results and solder joint profiles are employed towards a subsequent thermo-mechanical analysis of the full BGA assembly. The entire simulation procedure is demonstrated for a BGA design, where inelastic creep and reliability test data are compared. High strain regions in the solder joint array are shown to compare closely with regions of failure from experimental reliability test data. The validated FEM model allows for extrapolating to similar package conditions allowing faster design cycle time and less time consuming experimental work.

Exact First Order Finite Element Modeling for Eddy Current NDE

1991 ◽  
Vol 3 (1) ◽  
pp. 235-253 ◽  
Author(s):  
L. D. Philipp ◽  
Q. H. Nguyen ◽  
D. D. Derkacht ◽  
D. J. Lynch ◽  
A. Mahmood
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Eddy Current ◽  
Element Modeling ◽  
First Order ◽  
Eddy Current Nde

Tire Vibration Modes and Effects on Vehicle Ride Quality

1993 ◽  
Vol 21 (1) ◽  
pp. 23-39 ◽  
Author(s):  
R. W. Scavuzzo ◽  
T. R. Richards ◽  
L. T. Charek
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Operating Conditions ◽  
Modal Testing ◽  
Ride Quality ◽  
Vibration Modes ◽  
Inflation Pressure ◽  
Passenger Cars ◽  
Element Modeling ◽  
Road Surfaces

Abstract Tire vibration modes are known to play a key role in vehicle ride, for applications ranging from passenger cars to earthmover equipment. Inputs to the tire such as discrete impacts (harshness), rough road surfaces, tire nonuniformities, and tread patterns can potentially excite tire vibration modes. Many parameters affect the frequency of tire vibration modes: tire size, tire construction, inflation pressure, and operating conditions such as speed, load, and temperature. This paper discusses the influence of these parameters on tire vibration modes and describes how these tire modes influence vehicle ride quality. Results from both finite element modeling and modal testing are discussed.

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