scholarly journals Experimental Strain Energy Density Dissipated in SAC305 Solder Joints During Different Thermal Cycling Conditions Using Strain Gages Measurements

2018 ◽  
Author(s):  
Jean-Baptiste Libot ◽  
F. Dulondel ◽  
P. Milesi ◽  
J. Alexis ◽  
L. Arnaud ◽  
...  
Keyword(s):  
Energy Density ◽  
Thermal Cycling ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Solder Joints ◽  
Strain Gages ◽  
Sac305 Solder ◽  
Experimental Strain

scholarly journals Experimental SAC305 Shear Stress–Strain Hysteresis Loop Construction Using Hall's One-Dimensional Model Based on Strain Gages Measurements

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
J.-B. Libot ◽  
J. Alexis ◽  
O. Dalverny ◽  
L. Arnaud ◽  
P. Milesi ◽  
...  
Keyword(s):  
Shear Stress ◽  
Energy Density ◽  
Hysteresis Loop ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Solder Joints ◽  
Strain Gages ◽  
Sac305 Solder ◽  
Stress Strain ◽  
Temperature Cycles

Temperature-induced solder joint fatigue is a main reliability concern for aerospace and military industries whose electronic equipment used in the field is required to remain functional under harsh loadings. Due to the RoHS directive, which eventually will prevent lead from being utilized in electronic systems, there is a need for a better understanding of lead-free thermomechanical behavior when subjected to temperature variations. Characterizing solder joints properties remains a challenge as viscoplastic behavior during thermal cycling is complex, and their small dimensions prevent direct measurements from being performed. This paper reports the experimentation based on strain gage measurements, allowing the construction of the shear stress–strain hysteresis loop corresponding to Sn3.0Ag0.5Cu (SAC305) solder joints behavior during thermomechanical loading. This methodology, initially developed in 1984 by Hall for Sn60Pb40 interconnects, allows the measurement of the strain energy density dissipated during temperature cycles. Custom daisy-chained 76 I/O ceramic ball grid array (CBGA76) components were designed and assembled on flame retardant (FR-4) multilayered printed circuit boards (PCB). Four strain gages were specifically placed at the center of the assembly on top and bottom faces of both PCB and CBGA76 component. The assembly was subjected to temperature cycles and the SAC305 solder joints shear stress–strain hysteresis loop was plotted. The correlation between the measured strain energy density and measured lifetime corresponds to one point of the energy based fatigue curve for SAC305 solder joints. The hysteresis loop also provides the necessary data to derive SAC305 solder joints constitutive laws.

Critical Accumulated Strain Energy (Case) Failure Criterion for Thermal Cycling Fatigue of Solder Joints

1994 ◽  
Vol 116 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Tsung-Yu Pan
Keyword(s):  
Fatigue Life ◽  
Energy Density ◽  
Thermal Cycling ◽  
Creep Strain ◽  
Failure Criterion ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Solder Joints ◽  
Field Service ◽  
Accumulated Strain

In the automotive and computer industries, a perennial challenge has been to design an adequate and efficient accelerated thermal cycling test which would correspond to field service conditions. Failures, induced in both thermal cycle testing and field service, are characterized by thermal fatigue behavior. Several fatigue models have been proposed, none of these models take into account all of the many parameters of the test or service environment. In thermal cycling, for example, the temperature range, ramp rate, hold time, and stepped heating and cooling are known to influence the number of cycles to failure. In this study, a critical accumulated strain energy (CASE) failure criterion is proposed to correlate the fatigue life to both the plastic and creep strain energies, which accumulate in solder joints during the thermal cycling. This criterion suggests that solder joints fail as the strain energy accumulates and reaches a critical value. By using finite element analysis with a “ladder” procedure, both time-independent plastic strain energy and time-dependent creep strain energy are quantified. These are related to fatigue life by the equation: C = N*f (Ep + 0.13Ec), where C is the critical strain energy density, Nf is the fatigue life, Ep and Ec are plastic and creep strain energy density accumulation per cycle, respectively, for the eutectic Sn-Pb solders. By analyzing Hall and Sherry’s thermal cycling data (Hall and Sherry, 1986), it is found that creep is the predominant factor in deciding fatigue life. Creep accounts for 51 to 97 percent of the total accumulated strain energy, depending on the cycling profiles. This criterion is used to simulate crack propagation in a solder joint by analyzing the strain energy in small “domains” within the joint.

scholarly journals Creep-Fatigue Behaviours of Sn-Ag-Cu Solder Joints in Microelectronics Applications

2021 ◽  
Author(s):  
Joshua A. Depiver ◽  
Sabuj Mallik ◽  
Yiling Lu ◽  
Emeka H. Amalu
Keyword(s):  
Energy Density ◽  
Thermal Cycling ◽  
Strain Rate ◽  
Deformation Rate ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Solder Joints ◽  
Creep Fatigue ◽  
Accelerated Thermal Cycling ◽  
Isothermal Ageing

Electronic manufacturing is one of the dynamic industries in the world in terms of leading technological advancements. Electronic assembly’s heart lies the ‘soldering technology’ and the ‘solder joints’ between electronic components and substrate. During the operation of electronic products, solder joints experience harsh environmental conditions in terms of cyclic change of temperature and vibration and exposure to moisture and chemicals. Due to the cyclic application of loads and higher operational temperature, solder joints fail primarily through creep and fatigue failures. This paper presents the creep-fatigue behaviours of solder joints in a ball grid array (BGA) soldered on a printed circuit board (PCB). Using finite element (FE) simulation, the solder joints were subjected to thermal cycling and isothermal ageing. Accelerated thermal cycling (ATC) was carried out using a temperate range from 40°C to 150°C, and isothermal ageing was done at −40, 25, 75 and 150°C temperatures for 45 days (64,800 mins). The solders studied are lead-based eutectic Sn63Pb37 and lead-free SAC305, SAC387, SAC396 and SAC405. The results were analysed using the failure criterion of equivalent stress, strain rate, deformation rate, and the solders’ strain energy density. The SAC405 and SAC396 have the least stress magnitude, strain rate, deformation rate, and strain energy density damage than the lead-based eutectic Sn63Pb37 solder; they have the highest fatigue lives based on the damage mechanisms. This research provides a technique for determining the preventive maintenance time of BGA components in mission-critical systems. Furthermore, it proposes developing a new life prediction model based on a combination of the damage parameters for improved prediction.

Strain Energy Density Criterion for Reliability Life Prediction of Solder Joints in Electronic Packaging

2004 ◽  
Vol 126 (3) ◽  
pp. 398-405 ◽  
Author(s):  
I. Guven ◽  
V. Kradinov ◽  
J. L. Tor ◽  
E. Madenci
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Energy Density ◽  
Crack Growth ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Life Prediction ◽  
Solder Joints ◽  
Intrinsic Property ◽  
Electronic Packages

This study concerns the prediction of crack growth rate for solder joints in electronic packages under thermal cycling. The crack growth rate, which is dependent on the intrinsic solder property and the current stress state, is calculated based on the strain energy density criterion. The critical value of the strain energy density represents the intrinsic property of the solder. The comparison of the crack growth predictions with the experimental measurements demonstrates the applicability of the strain energy density criterion for the reliability life prediction of solder joints.

scholarly journals Volume free strain energy density method for applications to blunt V-notches

2020 ◽  
Vol 28 ◽  
pp. 734-742
Author(s):  
Pietro Foti ◽  
Seyed Mohammad Javad Razavi ◽  
Liviu Marsavina ◽  
Filippo Berto
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Density Method ◽  
Free Strain

scholarly journals On the application of the volume free strain energy density method to blunt V-notches under mixed mode condition

2021 ◽  
Vol 230 ◽  
pp. 111716
Author(s):  
Pietro Foti ◽  
Seyed Mohammad Javad Razavi ◽  
Majid Reza Ayatollahi ◽  
Liviu Marsavina ◽  
Filippo Berto
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Mixed Mode ◽  
Strain Energy ◽  
Density Method ◽  
Free Strain

scholarly journals Alternative derivation of the higher-order constitutive model for six-parameter elastic shells

2021 ◽  
Vol 72 (2) ◽  
Author(s):  
Mircea Bîrsan
Keyword(s):  
Energy Density ◽  
Constitutive Model ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Shell Theory ◽  
Constitutive Relations ◽  
Three Dimensional ◽  
Classical Shell Theory ◽  
Three Dimensional Elasticity ◽  
General Method

AbstractIn this paper, we present a general method to derive the explicit constitutive relations for isotropic elastic 6-parameter shells made from a Cosserat material. The dimensional reduction procedure extends the methods of the classical shell theory to the case of Cosserat shells. Starting from the three-dimensional Cosserat parent model, we perform the integration over the thickness and obtain a consistent shell model of order $$ O(h^5) $$ O ( h 5 ) with respect to the shell thickness h. We derive the explicit form of the strain energy density for 6-parameter (Cosserat) shells, in which the constitutive coefficients are expressed in terms of the three-dimensional elasticity constants and depend on the initial curvature of the shell. The obtained form of the shell strain energy density is compared with other previous variants from the literature, and the advantages of our constitutive model are discussed.

Storing Energy in the Mechanical Domain

2014 ◽  
Vol 1679 ◽  
Author(s):  
O.G. Súchil ◽  
G. Abadal ◽  
F. Torres
Keyword(s):  
Energy Source ◽  
Energy Density ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Critical Strain ◽  
Substrate Surface ◽  
Maximum Load ◽  
Linear Buckling ◽  
Initial Ph ◽  
Self Powered

ABSTRACTSelf-powered microsystems as an alternative to standard systems powered by electrochemical batteries are taking a growing interest. In this work, we propose a different method to store the energy harvested from the ambient which is performed in the mechanical domain. Our mechanical storage concept is based on a spring which is loaded by the force associated to the energy source to be harvested [1]. The approach is based on pressing an array of fine wires (fws) grown vertically on a substrate surface. For the fine wires based battery, we have chosen ZnO fine wires due the fact that they could be grown using a simple and cheap process named hydrothermal method [2]. We have reported previous experiments changing temperature and initial pH of the solution in order to determine the best growth [3]. From new experiments done varying the compounds concentration the best results of fine wires were obtained. To characterize these fine wires we have considered that the maximum load we can apply to the system is limited by the linear buckling of the fine wires. From the best results we obtained a critical strain of εc = 3.72 % and a strain energy density of U = 11.26 MJ/m3, for a pinned-fixed configuration [4].

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