Rise time and dwell time impact on Triac solder joints lifetime during power cycling

Abstract In this paper, the thermo-mechanical reliability of IMCs (Ni3Sn4, Cu3Sn, Cu6Sn5) solder joints and Sn-3.9Ag-0.6Cu solder joints were investigated systematically in 3D chip stacking structure subjected to an accelerated thermal cyclic loading based on finite element simulation and Taguchi method. Effects of different control factors, including high temperature, low temperature, dwell time of thermal cyclic loading, and different IMCs on the stress-strain response and fatigue life of solder joints were calculated respectively. The results indicate that maximum stress-strain can be found in the second solder joint on the diagonal of IMC solder joints array, for Sn-3.9Ag-0.6Cu solder joints array the corner solder joints shows the obvious maximum stress-strain, these areas are the crack propagated locations. The stress-strain and fatigue life of solder joints is more sensitive to dwell temperature, especially to high temperature, increasing the high temperature, dwell time, or decreasing the low temperature, can reduce the stress-strain and enlarge the fatigue life of solder joints. The optimal design in the 3D IC structure has the combination of the Cu6Sn5/Cu3Sn, 373K high temperature, 233K low temperature, and 10min dwell time.

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Investigation of Riveting Parameters Influence on the Riveted Joints Deformation During Slug Rivet Installation

Volume 2: Advanced Manufacturing ◽

10.1115/imece2016-66618 ◽

2016 ◽

Cited By ~ 3

Author(s):

Zhengping Chang ◽

Zhongqi Wang ◽

Jinming Zhang ◽

Yuan Yang ◽

Yonggang Kang

Keyword(s):

Rise Time ◽

Dwell Time ◽

Fem Simulation ◽

Dimensional Accuracy ◽

Quantitative Model ◽

Fe Model ◽

Clamping Force ◽

Orthogonal Experiments ◽

Riveted Joints ◽

Slug Rivet

Slug rivet is widely used in aircraft assembly due to the higher interference fit level and the longer fatigue life. However, the inhomogeneity of riveting interference value along the thickness direction of the aircraft panels always leads to inevitable deformation, which significantly degrades the dimensional accuracy of the final products. In this study, a quantitative model is established to describe the relationship between several riveting parameters (i.e. squeezing force, buck cavity, upsetting rise time, upsetting dwell time and clamping force between sheets) and the deformation of a formed slug rivet joint. Then the coefficient of variance (CV) is introduced to evaluate the homogeneity of deformation. Subsequently, an optimized combination of the presented parameters is obtained by using finite element method (FEM) simulation so as to generate more uniform deformation. Finally, the FEM model is validated by a series of orthogonal experiments conducted in G86 fully automated C-frame riveting machine and the results show that the squeezing force and the buck cavity are the main significant factors and contributors to the riveted joints deformation, and the sequence of this effect from the high to low are: upsetting dwell time, clamping force, and upsetting rise time. The results also indicate that the developed FE model can be used for further analysis, including the prediction of large component riveting deformation and the mechanical properties of riveted joint.

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