Constitutive Behavior and Low Cycle Thermal Fatigue of 97Sn-3Cu Solder Joints

1993 ◽  
Vol 115 (2) ◽  
pp. 147-152 ◽  
Author(s):  
Y.-H. Pao ◽  
S. Badgley ◽  
E. Jih ◽  
R. Govila ◽  
J. Browning
Keyword(s):  
Steady State ◽  
Constitutive Equation ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Steady State Creep ◽  
Creep Mechanism ◽  
Beam Specimen ◽  
Finite Element Program ◽  
Cyclic Shear ◽  
Element Program

The thermal cyclic shear stress/strain hysteresis response and associated steady-state creep parameters of 97Sn-3Cu solder joints have been determined using a beam specimen previously developed by Pao et al. (1992a). The solder joint was subjected to a 40-minute thermal cycling from 40°C to 140°C. A constitutive equation based on elastic and steady-state creep deformation for the solder has been formulated and implemented in a finite element program, ABAQUS, to model the experiment. The results show that the constitutive equation based on one single creep mechanism cannot fully account for the deformation during cooling, as opposed to the case of 90Pb-10Sn where the entire cyclic deformation can be well modeled by a similar constitutive equation (Pao et al., 1992c). This suggests that another creep mechanism is dominant for lower stresses and higher temperature. The thermal fatigue results show that the failure mechanism of 97Sn-3Cu joints is similar to that of 90Pb-10Sn joints, but the number of cycles to failure of 97Sn-Cu solder joints is at least 5 times longer than 90Pb-10Sn solder joints. This indicates the potential application of 97Sn-3Cu in place of 90Pb-10Sn solder.

An Experimental and Modeling Study of Thermal Cyclic Behavior of Sn-Cu and Sn-Pb Solder Joints

1993 ◽  
Vol 323 ◽  
Author(s):  
Y.-H. Pao ◽  
S. Badgley ◽  
R. Govila ◽  
E. Jah
Keyword(s):  
Solder Joints ◽  
Cyclic Behavior ◽  
Temperature Cycle ◽  
Beam Specimen ◽  
Finite Element Program ◽  
Creep Properties ◽  
Cyclic Shear ◽  
Double Beam ◽  
Element Program ◽  
Hysteresis Response

AbstractThermal cyclic shear stress/strain hysteresis response of 97Sn-2Cu-0.8Sb-0.2Ag, 95.5Sn-4Cu-0.5Ag, 63Sn-37Pb, and 62Sn-36Pb-2Ag solder joints have been determined using a double beam specimen. The temperature cycle had a period of 40 minutes and extreme temperatures of 40°C and 140°C.The steady state creep properties of these solders were determined, and the associated Norton's law was implemented in a finite element program to simulate the experiment. The fatigue life of these solders joints and failure mechanism are also discussed.

A Nonlinear and Time Dependent Finite Element Analysis of Solder Joints in Surface Mounted Components Under Thermal Cycling

1991 ◽  
Vol 226 ◽  
Author(s):  
Yi-Hsin Pao ◽  
Kuan-Luen Chen ◽  
An-Yu Kuo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Thermal Cycling ◽  
Solder Joints ◽  
Free Edge ◽  
Time Dependent ◽  
Element Analysis ◽  
Finite Element Program ◽  
Element Program ◽  
Peel Stress

AbstractA nonlinear and time dependent finite element analysis was performed on two surface mounted electronic devices subjected to thermal cycling. Constitutive equations accounting for both plasticity and creep for 37Pb/63Sn and 90Pb/10Sn solders were assumed and implemented in a finite element program ABAQUS with the aid of a user subroutine. The FE results of 37Pb/63Sn solder joints were in reasonably good agreement with the experimental data by Hall [19]. In the case of 9OPb/1OSn solder in a multilayered transistor stack, the FE results showed the existence of strong peel stress near the free edge of the joint, in addition to the anticipated shear stress. The effect of such peel stress on the crack initiation and growth as a result of thermal cycling was discussed, together with the singular behavior of both shear and peel stresses near the free edge.

A Comparative Study of the Response of Double Shearing and Hypoplastic Models

2002 ◽  
Author(s):  
Huaning Zhu ◽  
Morteza M. Mehrabadi ◽  
Mehrdad Massoudi
Keyword(s):  
Cyclic Loading ◽  
Mechanical Response ◽  
Constitutive Relations ◽  
Constitutive Models ◽  
Shear Loading ◽  
Biaxial Compression ◽  
Finite Element Program ◽  
Cyclic Shear ◽  
Hypoplastic Model ◽  
Element Program

The principal objective of this paper is to compare the mechanical response of a double shearing model with that of a hypoplastic model under biaxial compression and under cyclic shear loading. As the origins and nature of these two models are completely different, it is interesting to compare the predictions of these two models. The constitutive relations of the double shearing and the hypoplastic models are implemented in the finite element program ABACUS/Explicit. It is found that the hypoplastic and the double shearing constitutive models both show strong capability in capturing the essential behavior of granular materials. In particular, under the condition of non-cyclic loading, the stress ratio and void ratio predictions of the double shearing and the hypoplastic models are relatively close, while under the condition of cyclic loading, the predictions of these models are quite different. It is important to note that in the double shearing model employed in this comparison the shear rates on the two slip systems are assumed to be equal. Hence, the conclusions derived in this comparison pertain only to this particular double shearing model. Similarly, the hypoplasticity model considered here is that proposed by Wu, et al. [30] and the conclusions reached here pertain only to this particular hypoplasticity model.

scholarly journals Creep Mechanisms of an Al–Cu–Mg Alloy at the Macro- and Micro-Scale: Effect of the S′/S Precipitate

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2907 ◽  
Author(s):  
Yongqian Xu ◽  
Lingwei Yang ◽  
Lihua Zhan ◽  
Hailiang Yu ◽  
Minghui Huang
Keyword(s):  
Steady State ◽  
Steady State Creep ◽  
Creep Mechanism ◽  
Mg Alloy ◽  
Tensile Creep ◽  
Precipitate Size ◽  
Minor Role ◽  
Al Alloy ◽  
Creep Tests ◽  
Precipitate Growth

A novel methodology combining the macro- and micro-creep techniques was employed to study the effect of S′/S precipitate growth on the creep mechanism of an Al–Cu–Mg alloy. An AA2524 alloy was pre-aged at 180 °C to obtain S′/S precipitates with various sizes. The results showed that the precipitate size increased approximately linearly to ≈32 nm, ≈60 nm, and ≈105 nm after 3 h, 6 h, and 12 h of pre-aging, respectively. The growth of precipitate could significantly shorten the primary creep stage, despite the fact that the steady-state creep behavior was similar to that of the as-received alloy, as revealed by the macro tensile creep tests at 180 °C and 180 MPa. This led to a stress exponent (2.4–2.5) of the Al alloy with various precipitate sizes that was quite close to that of the as-received Al alloy, implying a steady-state creep mechanism dominated by grain boundary sliding and dislocation interactions. Finally, the micro-creep tests showed a minor role of the precipitate size on the steady-state creep mechanism, as evidenced by the similar strain rate sensitivity (0.0169–0.0186), activation volume (≈27 b3), and the results of a detailed transmission electron microscopy analysis of all tested alloys.

scholarly journals Effect of Anisotropic Interfacial Energy on Grain Boundary Distributions during Grain Growth

2004 ◽  
Vol 467-470 ◽  
pp. 733-738 ◽  
Author(s):  
Jason Gruber ◽  
Denise C. George ◽  
Andrew P. Kuprat ◽  
Gregory S. Rohrer ◽  
Anthony D. Rollett
Keyword(s):  
Steady State ◽  
Grain Boundary ◽  
Grain Growth ◽  
Energy Function ◽  
Boundary Energy ◽  
Grain Boundary Energy ◽  
Local Minima ◽  
Finite Element Program ◽  
Local Maxima ◽  
Element Program

Through simulations with the moving finite element program GRAIN3D, we have studied the effect of anisotropic grain boundary energy on the distribution of boundary types in a polycrystal during normal grain growth. An energy function similar to that hypothesized for magnesia was used, and the simulated grain boundary distributions were found to agree well with measured distributions. The simulated results suggest that initially random microstructures develop nearly steady state grain boundary distributions that have local maxima and minima corresponding to local minima and maxima, respectively, of the energy function.

A Simple Method of Handling Thermomechanical Coupling for Temperature Computation in a Rolling Tire

2004 ◽  
Vol 32 (2) ◽  
pp. 56-68 ◽  
Author(s):  
S. Futamura ◽  
A. Goldstein
Keyword(s):  
Steady State ◽  
Material Properties ◽  
Thermomechanical Analysis ◽  
Temperature Dependent ◽  
Finite Element Program ◽  
Steady State Analysis ◽  
User Subroutine ◽  
Simplified Method ◽  
Element Program ◽  
Fully Coupled

Abstract The thermomechanical analysis of a pneumatic tire is a highly complex process due to the effects of temperature on both the mechanical state and the viscoelastic energy dissipation in the tire. This coupled thermomechanical behavior typically requires that rolling tire temperatures be determined iteratively. As a result, a steady-state analysis involves updating the temperature dependent elastic and viscoelastic properties as the solution proceeds. The process is further complicated in a non-steady-state analysis where material properties need to be updated at multiple intervals in time. A simplified method is proposed. First, the sensitivity of the tire elastic response of the tire to changes in material stiffness is characterized using the “deformation index”. Then, using a commercial finite element program and an appropriate user subroutine, heat generation is expressed as a function of the local temperature using a simple algebraic expression involving the temperature dependent material properties and the deformation indices. Temperatures are computed using the finite element program with the coupling information contained in the user subroutine. The result is a simplified method for a fully coupled thermomechanical analysis of a tire for steady-state and transient thermal analysis. The accuracy and the simplicity of the method are demonstrated using a small “tire-like” model. The simplified method is compared to the fully coupled iterative method for a steady-state thermal solution.

Numerical Modeling of Shape Memory Alloy Thin Film Actuators and Their Applications

2006 ◽  
Vol 321-323 ◽  
pp. 186-191 ◽  
Author(s):  
Jin Ho Roh ◽  
Jae Hung Han ◽  
In Lee
Keyword(s):  
Thin Film ◽  
Finite Element ◽  
Numerical Modeling ◽  
Constitutive Equation ◽  
Numerical Algorithm ◽  
Thermomechanical Behavior ◽  
Alloy Thin Film ◽  
Finite Element Program ◽  
Membrane Pump ◽  
Element Program

The thermomechanical behavior of SMA thin film actuator and their application are investigated. The numerical algorithm of the 2-D SMA thermomechanical constitutive equation is developed using user material (UMAT) subroutine written by FORTRAN. For the numerical results of SMA thin film, the ABAQUS finite element program has been utilized with UMAT subroutine of the numerical algorithm of SMA. The application of SMA thin film for the membrane pump actuator is demonstrated.

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