Optimized Design of Various Ag Decorated Sn-xAg-Cu0.7 Solder Bump on Cycling Fatigue Reliability for Wafer-Level Chip Scale Packaging

2021 ◽  
Author(s):  
Hwa-Teng Lee ◽  
Ching-Yuan Ho ◽  
Chao Chin Lee
Keyword(s):  
Eutectic Point ◽  
Optimized Design ◽  
Fatigue Reliability ◽  
Wafer Level ◽  
Fatigue Lifetime ◽  
Coexistence Phase ◽  
Ag Additions ◽  
Plastic Displacement ◽  
Solid Liquid ◽  
Solder Interface

Abstract Effects of Ag content (0 ~ 3 wt.%) in Sn-xAgCu0.7 solders on microstructure characteristics and low cycling fatigue at different temperature conditions are overall investigated. To increase Ag content, the solidus point 228.8 ? of Sn-Cu0.7 gradually decreases to 218.5 ? and temperature range of solid-liquid coexistence phase is also decrease. The Sn-Cu0.7 matrix consisted of small particles of Cu6Sn5 within ß-Sn equiaxial grains and did not significantly influence solder hardness. Moreover, much intermetallic compound of plate-like Ag3Sn and rod-like Cu6Sn5 existed in Sn-xAgCu0.7 solders enables to enhance the hardness due to dense network of Ag3Sn precipitation and near eutectic point. As a result of plastic displacement decreases with higher Ag additions, better fatigue lifetime could be achieved at Ag content to 1.5 wt.%. Besides, crack stemmed from thicker IMC layer in Sn-3.0Ag-Cu0.7 solder interface will decrease fatigue performance especially for 80 ? and 120 ?.

scholarly journals Reinforced concrete bridge pier ductility analysis for different levels of detailing

2017 ◽  
Vol 10 (5) ◽  
pp. 1042-1050
Author(s):  
R. W. SOARES ◽  
S. S. LIMA ◽  
S. H. C. SANTOS
Keyword(s):  
Reinforced Concrete ◽  
Axial Loading ◽  
Structural Element ◽  
Reinforced Concrete Column ◽  
Elastoplastic Behavior ◽  
Response Modification Factor ◽  
Concrete Confinement ◽  
Plastic Displacement ◽  
Displacement Based ◽  
Ductility Capacity

Abstract The structural design under seismic loading has been for many years based on force methods to consider the effects of energy dissipation and elastoplastic behavior. Currently, displacement-based methods are being developed to take into account elastoplastic behavior. These methods use moment-curvature relationships to determine the ductility capacity of a structural element, which is the deformation capacity of the element before its collapse. The greater the plastic displacement or rotation a structural member can achieve before it collapses, the more energy it is capable of dissipating. This plastic displacement or rotation capacity of a member is known as the member ductility, which for reinforced concrete members is directly related to efficient concrete confinement. This study investigates at which extents transverse reinforcement detailing influences reinforced concrete column ductility. For this, a bridge located in Ecuador is modeled and analyzed, and its ductility evaluated considering several cases of axial loading and concrete confinement levels. After the performed displacement-based analyses, it is verified whether the response modification factor defined by AASHTO is adequate in the analyzed case.

Indentation plastic displacement field: Part I. The case of soft films on hard substrates

1999 ◽  
Vol 14 (6) ◽  
pp. 2196-2203 ◽  
Author(s):  
T. Y. Tsui ◽  
Joost Vlassak ◽  
William D. Nix
Keyword(s):  
Plastic Deformation ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Porous Titanium ◽  
Titanium Layer ◽  
Plastic Deformation Behavior ◽  
Plastic Displacement ◽  
Film Substrate ◽  
Made In

The plastic deformation behavior of Knoop indentations made in a soft, porous titanium/aluminum multilayered thin film on a hard silicon substrate is studied through use of the focused-ion-beam milling and imaging technique. Pileup is observed for indentations with depths larger than 30% of the total film thickness. Analysis of the indentation cross sections shows that plastic deformation around the indentation is partly accommodated by the closing of the pores within the multilayers. This densification process reduces the amount of pileup formed below that predicted by finite element simulations. Experimental results show that the pileup is formed by an increase of the titanium layer thickness near the edges of the indentation. The thickness increase is largest near the film/substrate interface and decreases toward the surface of the multilayered film. The amount of normal compression near the center of the indenter is characterized, and it is demonstrated that the deformation becomes more nonuniform with increasing indentation depth.

Estimation Accuracy of Absolute Maximum Elasto-Plastic Displacements of MDOF Oscillators Based on a Modal Combination Rule With Post-Yielding Modal Properties and Linear Response Spectrum Values

2018 ◽  
Author(s):  
Tomoyo Taniguchi ◽  
Yoshihiko Toda ◽  
Yusuke Ono ◽  
Kyosuke Mukaibo
Keyword(s):  
Response Spectrum ◽  
Time History ◽  
Degree Of Freedom ◽  
Estimation Accuracy ◽  
Absolute Maximum ◽  
Earthquake Excitation ◽  
Linearized System ◽  
The Absolute ◽  
Plastic Displacement ◽  
Mode 3

Taniguchi, et al. [1] developed an analytical method for evaluating the absolute maximum elasto-plastic displacements of multi-degree-of-freedom (MDOF) oscillators under the action of base excitation based on a modal combination. Its essence is that 1) modal frequencies, shapes and damping during yielding of any member of the MDOF oscillators are readily specified by the modal analysis with the secondary stiffness of the members being yielded, 2) assuming that a bilinear hysteresis may describe the force-displacement relationship of each mode, an equivalently linearized system consisting of a single-degree-of-freedom (SDOF) oscillator is introduced to approximate the absolute maximum elasto-plastic displacement of each mode, 3) the absolute maximum elasto-plastic displacement of the MDOF oscillator is evaluated by the Square Root of Sum of Squares rule (SRSS-rule) by combining the maximum elasto-plastic displacement of each mode approximated by the proposed equivalently linearized system. This study first provides small modification in the equivalently linearized system. Then, employing a couple of MDOF oscillators whose spring at arbitrary storey may yield and an accelerogram, the maximum elasto-plastic displacement of the MDOF oscillator is calculated by the proposed method and is compared with that computed by the time history analysis. Their comparison suggests that the proposed method can reasonably evaluate the absolute maximum elasto-plastic displacement of the MDOF oscillator subjected to earthquake excitation as the conventional SRSS-rule does that for the linear MDOF oscillators.

scholarly journals Experimental Study on Load-Displacement Relationship of Prestressed Cable in Red Clay Stratum

2018 ◽  
Vol 38 ◽  
pp. 03007
Author(s):  
Yong Xing Ji ◽  
Yuan Jie Xiang ◽  
Xiao Yong Zhao
Keyword(s):  
Damage Index ◽  
Theoretical Models ◽  
Exponential Model ◽  
Red Clay ◽  
Anchor Cable ◽  
Pull Out ◽  
S Curve ◽  
Plastic Displacement ◽  
Relationship Of ◽  
Prestressed Anchor

The P-S curves of prestressed anchor cable are obtained by field pull-out tests in the red-clay stratum in Guiyang area. The P-S curves of different theoretical models are discussed base on the theoretical analysis. The elastic and plastic displacement of prestressed anchor cable are analyzed. The results shows that, the anchoring effect are mainly effected by the red-clay mechanic properties in the red-clay stratum; the P-S curve of anchor bolt can be fitted well by the exponential model and conformed to the actual; the plastic displacement is used to anchor’s damage index are more truthfulness in the red-clay stratum.

Displacement-Based Assessment of Seismic Resistance for Transfer Structure with Haunching Braces

2011 ◽  
Vol 243-249 ◽  
pp. 557-562
Author(s):  
Wei Sheng Liang ◽  
Jian Cai
Keyword(s):  
Seismic Resistance ◽  
Engineering Practice ◽  
Seismic Events ◽  
Feature Based ◽  
New Type ◽  
Beam Type ◽  
Plastic Displacement ◽  
Transfer Structure ◽  
Displacement Based ◽  
Resistance Performance

The beam-type transfer structure has recently been well adopted in multi-purpose buildings. A new type of transfer structure with haunching braces is introduced in this paper through static elasto-plastic analysis of example structure with specific focus on its unique feature. Based of the deformation damaged criteria, seismic resistance performance for transfer structure with haunching braces is assessed. The results indicate that elastic and elasto-plastic displacement of structure under minor, medium and major seismic events designed against 7 degree seismic fortification intensity satisfy the requirement of the current standards, the structure’s damage status under minor and medium seismic events is Almost Intact and the structure’s damage status under major seismic events is Minor Damage. It can provide reference for engineering practice.

scholarly journals Modal Approximation Based Optimal Design of Dynamically Loaded Plastic Structures

2017 ◽  
Author(s):  
Bartlomiej Dominik Blachowski ◽  
Piotr Tauzowski ◽  
Janos Logo
Keyword(s):  
Optimal Design ◽  
Deformation Process ◽  
Minimum Weight ◽  
Optimization Technique ◽  
Design Procedure ◽  
Inertial Forces ◽  
Constant Acceleration ◽  
Weight Structure ◽  
Plastic Displacement

The purpose of this study is to present an optimal design procedure for elasto-plastic structures subjected to impact loading. The proposed method is based on mode approximation of the displacement field and assumption of constant acceleration of impacted structure during whole time of deformation process until the plastic displacement limit is reached. Derivation of the method begins with the application of the principle of conservation of linear momentum, followed by determination of inertial forces. The final stage of the method utilizes an optimization technique in order to find a minimum weight structure. Eventually, effectiveness and usefulness of the proposed method is demonstrated on the example of a planar truss structure subjected to dynamic loading caused by a mass impacting the structure with a given initial velocity.

ON CONTROL PERFORMANCE OF MULTI-D.O.F. ELASTIC-PLASTIC STRUCTURES UNDER EARTHQUAKES

2001 ◽  
Vol 01 (04) ◽  
pp. 561-583
Author(s):  
A. BARATTA ◽  
O. CORBI
Keyword(s):  
Control Algorithm ◽  
Ad Hoc ◽  
Control Model ◽  
Linear Control ◽  
Control Performance ◽  
Structural System ◽  
Elastic Plastic ◽  
Dynamic Excitation ◽  
Numerical Tests ◽  
Plastic Displacement

In this paper, a control algorithm developed for a single-d.o.f. elastic-plastic structural system subjected to a dynamic excitation is presented. The algorithm is based on evaluation of the bounds for plastic displacement occurring during the motion1–7 and it can be regarded as an extension of the optimal norm control8,9 which works for structures with no plastic excursion. Analytical foundations and numerical tests are carried out, providing some general conclusions on the advantage of adopting an ad hoc non-linear control model and on its applicability to elastic-plastic structures.

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