Mechanical/Plasma Decapsulation Method and Thermal Finite-Element Analysis Provide Explanation for SMB Zener Failures

1998 ◽  
Author(s):  
Kent Kime ◽  
Chuck Reed ◽  
Joe Di Silvestro ◽  
Ruth Ruiz ◽  
Simon Keeton ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Analysis ◽  
Recent Change ◽  
Test Duration ◽  
Zener Diode ◽  
Element Analysis ◽  
Test Parameters ◽  
Die Surface ◽  
Transient Thermal

Abstract Failure analysis and finite-element analysis were used in conjunction to determine the cause of zener diode failures. A mechanical/plasma depot method was developed for the plastic-encapsulated SMB package and used to observe the presence of remelted extruded solder material on the die surface. That material provided a conductive path which manifested electrically as premature breakdown. Transient-thermal finite-element analysis was then used to show that a recent change of in-house surge test parameters could result in part temperatures during surge testing in excess of the solder melting temperature. These efforts lead to a respecification of the in-house surge test duration which resolved the problem.

Comprehending Occurrence of Premature Failure in Compressor Turbine (CT) Blades for Short-Haul Aircraft Fleet

2019 ◽  
Vol 42 ◽  
pp. 10-23
Author(s):  
Joshua Kimtai Ngoret ◽  
Venkata Parasuram Kommula
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Thermal Stresses ◽  
Geometrical Model ◽  
Mechanical Stresses ◽  
Element Analysis ◽  
Premature Failure ◽  
Structural Stresses ◽  
Transient Thermal

This paper presents results from modeling of Compressor Turbine (CT) blades for short-haul aircraft fleet occasioned by thermo-mechanical stresses in order to comprehend the occurrence of premature failure. A 3D PT6A-114A engine high pressure (HP) CT blade geometrical model was developed in commercial CAD-SolidWorks, then imported to ANSYS 15.0 environment for finite element analysis (FEA). The CT blade was investigated for transient thermal stresses from heat generated by the combustors and static structural stresses from rotational velocities of the engine which account for 80% of inertial field during flight. The results revealed that the blades could have served for another 1.44% of the time they were in service.

Failure analysis of pressure vessel with sight ports using finite element analysis

2020 ◽  
Vol 117 ◽  
pp. 104791
Author(s):  
Nitikorn Noraphaiphipaksa ◽  
Piyamon Poapongsakorn ◽  
Anat Hasap ◽  
Chaosuan Kanchanomai
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Analysis ◽  
Pressure Vessel ◽  
Element Analysis

“STRUCTURE ANALYSIS, CONTACT STRESS ANALYSIS AND FATIGUE LIFE ANALYSIS OF SPUR GEAR ASSEMBLY BY USING FEM”

2018 ◽  
Vol 4 (4) ◽  
pp. 13
Author(s):  
Anand Mohan Singh ◽  
Megha Bhawsar ◽  
Neeraj Kumar Nagayach
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Failure Analysis ◽  
Contact Stress ◽  
Spur Gear ◽  
Contact Analysis ◽  
Element Analysis ◽  
Life Analysis ◽  
Fatigue Life Analysis

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.

Evaluation of Dynamic Performance of Aircraft Seats for Larger Passenger Population Using Finite Element Analysis

2012 ◽  
Author(s):  
Prasannakumar S. Bhonge ◽  
Rasoul Moradi ◽  
Hamid M. Lankarani
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Integrity ◽  
Dynamic Testing ◽  
Dynamic Performance ◽  
General Aviation ◽  
Element Analysis ◽  
Sled Test ◽  
Passenger Seat ◽  
Test Parameters

Dynamic aircraft seat regulations are identified in the Code of Federal Regulations (CFR), 14 CFR Parts § XX.562 for crashworthy evaluation of a seat in dynamic crash environment. The regulations specify full-scale dynamic testing on production seats. The dynamic tests are designed to demonstrate the structural integrity of the seat to withstand an emergency landing event and occupant safety. These tests are carried out on a 50th percentile Hybrid II Anthropomorphic Test Device (ATD) representing average 50 percent of human population. In this study, the dynamic performance of seats are evaluated for larger passenger population for both transport and general aviation seats. For this, Finite Element Analysis (FEA) of an aircraft seat model is analyzed by utilizing a 50th percentile e-ATD and validated with a 50th percentile ATD sled test results. Then the effect of a 95th percentile standard ATD in an aircraft passenger seat is investigated using FEA. Comparison of the 50th percentile and the 95th percentile electronic ATD models (e-ATDs) is carried out on the test parameters. This includes the restraint loads, the floor reactions and the head paths. Based on the comparison it is concluded that the seat loads go up in the range of 20 to 30% if designed for larger passenger population.

Finite Element Analysis of Die-Strength Testing Configurations for Thin Wafers

2004 ◽  
Vol 127 (2) ◽  
pp. 189-192 ◽  
Author(s):  
X. K. Sun ◽  
X. J. Xin ◽  
Z. J. Pei
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Gradient ◽  
Strength Testing ◽  
Uniform Stress ◽  
Element Analysis ◽  
Ring Configuration ◽  
Die Surface ◽  
Uniform Stress Field ◽  
Point Bend

This paper presents an assessment of four die-strength testing configurations using finite element analysis. The simulation indicates that ring-on-ring configuration is the best because it generates a uniform stress field on a large die surface area. The four-point-bend configuration ranks second and the three-point-bend configuration is third. The pin-on-ring configuration is the worst because the stress gradient is severe in the central region. To minimize uncertainty in the loading positions, it is advised that loading rings or bars with small radii be used.

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