A Global–Local Approach for Mechanical Deformation and Fatigue Durability of Microelectronic Packaging Systems

2006 ◽  
Vol 129 (2) ◽  
pp. 179-189 ◽  
Author(s):  
T. Zhang ◽  
S. Rahman ◽  
K. K. Choi ◽  
K. Cho ◽  
P. Baker ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Thermal Loading ◽  
Ball Grid Array ◽  
Mechanical Deformation ◽  
Equivalent Model ◽  
Joint Analysis ◽  
Deformation Analysis ◽  
Fatigue Durability ◽  
Durability Analysis ◽  
Global Deformation

This paper presents a global–local methodology for predicting mechanical deformation and fatigue durability of solder joints in electronic packaging systems subject to cyclic thermal loading. It involves a global deformation analysis, a local critical solder–joint analysis, and a fatigue life analysis. The global deformation analysis includes a new optimization formulation for determining an equivalent model. The methodology developed was applied to fine pitch ball grid array (fpBGA) and super ball grid array (SBGA) packages. Selective experimental efforts were also undertaken to evaluate the predicted deformation characteristics of the fpBGA package. A good agreement was obtained between the simulated deformation results and experimental observations. For the durability analysis, the total fatigue life predicted using the energy-based method is larger than 2500 cycles—a trend observed experimentally for both packages entailing widely different designs. Based on proposed modeling and simulation results and package designs studied, the SBGA package is more durable than the fpBGA package.

Random impact FEM simulation of irregularly-shaped media for parametric study of vibratory surface enhancement

2021 ◽  
pp. 095440542199012
Author(s):  
Jing Zhang ◽  
Joselito Yam Alcaraz ◽  
Swee-Hock Yeo ◽  
Arun Prasanth Nagalingam ◽  
Abhay Gopinath
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Parametric Study ◽  
Thermal Loading ◽  
Low Cycle Fatigue ◽  
Fem Simulation ◽  
Surface Finishing ◽  
Aerospace Materials ◽  
Surface Enhancement ◽  
Steel Balls

Aerospace materials experience high levels of mechanical and thermal loading, high/low cycle fatigue, and damage from foreign objects during service, which can lead to premature retirement. Mechanical surface treatments of metallic components, for example, fan blades and blisks, are proven to improve fatigue life, improve wear resistance and avoid stress corrosion by introducing work hardening, compressive residual stresses of sub-surface, and surface finishing. Vibropeening can enhance aerospace materials’ fatigue life involving the kinetic agitation of hardened steel media in a vibratory finishing machine that induces compressive stresses into the component sub-layers while keeping a finished surface. Spherical steel balls are the most widely used shape among steel-based media and have been explored for decades. However, they are not always versatile, which cannot access deep grooves, sharp corners, and intricate profiles. Steel ballcones or satellites, when mixed with round steel balls and other steel media (diagonals, pins, eclipses, cones), works very well in such areas that ball-shaped media are unable to reach. However, a methodology of study the effect of irregularly-shaped media in surface enhancement processes has not been established. This paper proposes a finite element-based model to present a methodology for the parametric study of vibratory surface enhancement with irregularly-shaped media and investigates residual stress profiles within a treated area of an Inconel component. The methodology is discussed in detail, which involves a stochastic simulation of orientation, impact force, and impact location. The contrasting effects of a high aspect ratio, or an edge contact, as opposed to rounded and oblique contacts are demonstrated, with further analysis on the superposition of these effects. Finally, the simulation results are compared with actual residual stress measurements and was found to have a max percent difference of 34% up to 20 [Formula: see text]m below the media surface.

Durability Analysis of the Reduction Gear for High Speed Train Considering Driving Histories

2012 ◽  
Vol 586 ◽  
pp. 269-273
Author(s):  
Chul Su Kim ◽  
Gil Hyun Kang
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Element Model ◽  
Rolling Stock ◽  
Reduction Gear ◽  
High Speed Train ◽  
Analysis Software ◽  
Tractive Effort ◽  
Durability Analysis ◽  
The Finite Element Model

To assure the safety of the power bogies for train, it is important to perform the durability analysis of reduction gear considering a variation of velocity and traction motor capability. In this study, two types of applied load histories were constructed from driving histories considering the tractive effort and the train running curves by using dynamic analysis software (MSC.ADAMS). Moreover, this study was performed by evaluating fatigue damage of the reduction gears for rolling stock using durability analysis software (MSC.FATIGUE). The finite element model for evaluating the carburizing effect on the gear surface was used for predicting the fatigue life of the gears. The results showed that the fatigue life of the reduction gear would decrease with an increasing numbers of stops at station.

Validation of the Critical Strain-Based Methodology for Evaluating the Mechanical Safety of Ball Grid Array Solder Joints in a Launch Random Vibration Environment

2021 ◽  
Author(s):  
Tae-Yong Park ◽  
Hyun-Ung Oh
Keyword(s):  
Fatigue Life ◽  
Random Vibration ◽  
Critical Strain ◽  
Printed Circuit Board ◽  
Solder Joints ◽  
Mechanical Design ◽  
Ball Grid Array ◽  
Primary Objective ◽  
Circuit Board ◽  
Analytical Approaches

Abstract To overcome the theoretical limitations of Steinberg's theory for evaluating the mechanical safety of the solder joints of spaceborne electronics in a launch random vibration environment, a critical strain-based methodology was proposed and validated in a previous study. However, for the critical strain-based methodology to be used reliably in the mechanical design of spaceborne electronics, its effectiveness must be validated under various conditions of the package mounting locations and the first eigenfrequencies of a printed circuit board (PCB); achieving this validation is the primary objective of this study. For the experimental validation, PCB specimens with ball grid array packages mounted on various board locations were fabricated and exposed to a random vibration environment to assess the fatigue life of the solder joint. The effectiveness of the critical strain-based methodology was validated through a comparison of the fatigue life of the tested packages and their margin of safety, which was estimated using various analytical approaches.

Micro-Mechanical Deformation Analysis of Surface Laminar Circuit in Organic Flip-Chip Package: An Experimental Study

2000 ◽  
Vol 122 (4) ◽  
pp. 294-300 ◽  
Author(s):  
B. Han ◽  
P. Kunthong
Keyword(s):  
Flip Chip ◽  
Thermal Loading ◽  
Region Of Interest ◽  
Deformation Analysis ◽  
High Modulus ◽  
Displacement Fields ◽  
Complex Deformation ◽  
Mechanical Deformations ◽  
Displacement Sensitivity ◽  
Package Reliability

Thermo-mechanical deformations of microstructures in a surface laminar circuit (SLC) substrate are quantified by microscopic moire´ interferometry. Two specimens are analyzed; a bare SLC substrate and a flip chip package assembly. The specimens are subjected to a uniform thermal loading of ΔT=−70°C and the microscopic displacement fields are documented at the identical region of interest. The nano-scale displacement sensitivity and the microscopic spatial resolution obtained from the experiments provide a faithful account of the complex deformation of the surface laminar layer and the embedded microstructures. The displacement fields are analyzed to produce the deformed configuration of the surface laminar layer and the strain distributions in the microstructures. The high modulus of underfill produces a strong coupling between the chip and the surface laminar layer, which produces a DNP-dependent shear deformation of the layer. The effect of the underfill on the deformation of the microstructures is investigated and its implications on the package reliability are discussed. [S1043-7398(00)01304-9]

Space Optical Remote Sensor of the CAE Thermal Control Index Calculation Method

2011 ◽  
Vol 308-310 ◽  
pp. 2328-2333
Author(s):  
Li Fu Li
Keyword(s):  
Optical System ◽  
Thermal Loading ◽  
Surface Deformation ◽  
Thermal Control ◽  
Temperature Fields ◽  
Deformation Analysis ◽  
Analysis Model ◽  
Zernike Polynomial ◽  
Remote Sensors ◽  
Remote Sensor

The thermal control indicators CAE methods of Space optical remote sensor are analyzed in the presented work. We sat up a thermal optical analysis model for space optical remote sensor. By assuming fully covered by in-orbit temperature load, and using the finite element method for thermal deformation analysis, we obtained the optical remote sensor surface deformation and displacement under various thermal loading. Using ZERNIKE polynomial, wave was fitted to obtain ZERNIKE polynomial coefficients which were incorporated into the optical system design. Using CODE V optical calculation software, heat-ray machines under elastic deformation of the system point spread function, transfer function (MTF), wave front differential (WFE) etc. were calculated. Image quality changes of remote sensors are discussed in variety assumed cases such as temperature loads of quality change. By repeated iteration, critical value of temperature fields meeting the design requirements are obtained for the optical system. Optical indicators were converged to the temperature field indicator, then reasonable indicators of thermal control for remote sensors were obtained. For the thermal control design, this method provided a reliable basis for design.

Study on the Choice of Constitutive and Fatigue Models in Solder Joint Life Prediction

2002 ◽  
Author(s):  
Krishna Tunga ◽  
James Pyland ◽  
Raghuram V. Pucha ◽  
Suresh K. Sitaraman
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Solder Joint ◽  
Predictive Models ◽  
Life Prediction ◽  
Constitutive Models ◽  
Ball Grid Array ◽  
Time Dependent ◽  
Dependent Behavior ◽  
Ball Grid Array Packages

Various constitutive and fatigue-life predictive models for lead-tin solders in SBGA (Super Ball Grid Array) packages are studied and compared with the results from experimental data. Two solder compositions, 62Sn/36Pb/2Ag and 63Sn/37Pb are studied in this work. The fatigue life of 62Sn/36Pb/2Ag solder is studied using different constitutive models that take into consideration both the time-independent and time-dependent behavior of the solder. The fatigue life of 62Sn/36Pb/2Ag solder is predicted using an energy-based predictive model and compared with the experimental data. The choice of various predictive models on the solder joint life is studied using 63Sn/37Pb solder. Various predictive models, available in the literature, for eutectic and near eutectic solder compositions are studied to predict the fatigue life. Guidelines are provided for selecting constitutive and predictive models with appropriate damage metrics.

A Study on Fatigue and Creep-Fatigue Life Assessment Using Cyclic Thermal Tests With Mod.9Cr-1Mo Steel Structures

2012 ◽  
Author(s):  
Masanori Ando ◽  
Hiroshi Kanasaki ◽  
Shingo Date ◽  
Koichi Kikuchi ◽  
Kenichiro Satoh ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Temperature Distribution ◽  
Crack Initiation ◽  
Thermal Loading ◽  
Life Assessment ◽  
Estimation Methods ◽  
Short Term ◽  
Cyclic Thermal Loading ◽  
Fatigue Life Assessment ◽  
Creep Fatigue

In a component design at elevated temperature, fatigue and creep-fatigue is one of the most important failure modes, and fatigue and creep-fatigue life assessment in structural discontinuities is important issue to evaluate structural integrity of the components. Therefore, to assess the failure estimation methods, cyclic thermal loading tests with two kinds of cylindrical models with thick part were performed by using an induction heating coil and pressurized cooling air. In the tests, crack initiation and propagation processes at stress concentration area were observed by replica method. Besides those, finite element analysis (FEA) was carried out to estimate the number of cycles to failure. In the first test, a shorter life than predicted based on axisymmetric analysis. Through the 3 dimensional FEA, Vickers hardness test and deformation measurements after the test, it was suggested that inhomogeneous temperature distribution in hoop direction resulted in such precocious failure. Then, the second test was performed after improvement of temperature distribution. As a result, the crack initiation life was in a good agreement with the FEA result by considering the short term compressive holding. Through these test and FEA results, fatigue and creep-fatigue life assessment methods of Mod.9Cr-1Mo steel including evaluation of cyclic thermal loading, short term compressive holding and failure criterion, were discussed. In addition it was pointed out that the temperature condition should be carefully controlled and measured in the structural test with Mod.9Cr-1Mo steel structure.

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