Research Papers

Successive Softening and Cyclic Damage in Viscoplastic Material

[+] Author and Article Information
Leila J. Ladani

Department of Mechanical Engineering, University of Alabama, Tuscaloosa, AL 35487lladani@eng.ua.edu

J. Electron. Packag 132(4), 041011 (Dec 08, 2010) (7 pages) doi:10.1115/1.4002722 History: Received March 17, 2010; Revised July 08, 2010; Published December 08, 2010; Online December 08, 2010

A successive initiation finite element modeling approach is presented in which an empirical continuum damage model, energy partitioning damage evolution model, developed by the author is used to update state of damage and constitutive properties of the material under thermomechanical cyclic loading and accumulate damage in the elements. Plastic and viscoplastic damages are evaluated based on the plastic and viscoplastic work densities obtained through finite element. Constitutive properties are updated elementwise at each step of the process based on the state of damage in each element. The elements that have reached the damage threshold are removed from the structure to initiate and propagate fatigue crack. This successive initiation approach is used to model crack initiation and propagation in Pb-free solder material under thermomechanical loading. A case study is presented, damage propagation path and pattern are compared with typical experimental results, and the accuracy of the model was verified.

Copyright © 2010 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 1

Example of hysteresis loops at 25°C, strain rate of 0.05 s−1 and inelastic strain range of 0.04 for SAC solder

Grahic Jump Location
Figure 2

Flow chart for successive propagation methodology

Grahic Jump Location
Figure 3

Schematic of damage update and rate change as function of number of cycles

Grahic Jump Location
Figure 4

Global finite element analysis for BGA132, with applied boundary conditions

Grahic Jump Location
Figure 5

Contour plot of equivalent stress in solder balls

Grahic Jump Location
Figure 6

(a) Contour plot of damage calculated using E-P damage model in local mode and (b) killed elements and updated properties for the remaining elements (each individual color indicates an element with a different constitutive properties)

Grahic Jump Location
Figure 7

Contour plot of creep strain energy for four steps of damage propagation. Elements around the joint that are killed as a result of damage propagation and do not accumulate any creep work

Grahic Jump Location
Figure 8

Damage path observed in dye and pry



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In