What's New - January 2012
CALCE
and AMSAA Show Value of Multi-Axis Vibration Tests
 |
|
Modal Shape of Test Specimen Subject to Multi-axis Vibration Loading
|
|
US Army Materiel Systems Analysis Activity (AMSAA) and the Center for Advanced Life Cycle Engineering (CALCE) at the University of Maryland have engaged in a
joint effort to develop test methods and analytical models that better capture unforeseen design weaknesses prior to the qualification phase by improved
replication of life-cycle vibration conditions. As a result of this effort, a novel multi-degrees-of-freedom (M-DoF) electrodynamic shaker was designed
in order to ruggedize designs for fatigue damage due to multi-directional random vibration. There is a potential for M-DoF to detect critical
design vulnerabilities earlier in the development cycle than has been traditionally possible with existing shaker technologies. Therefore, the
new methods produce more cost-effective, reliable, and safe electronic systems. This testing approach is particularly useful for the next generation
of portable and autonomous systems that are strongly dependent on the reliability of electronics-rich devices. Thus, the performance and accuracy of
these systems will be dependent on the life cycle of electronics. These electronic systems and the critical components in them experience extremely
harsh environments such as shock and vibration. Therefore, it is imperative to identify the failure mechanisms of these components through experimental and
virtual failure assessment. One of the key challenges in re-creating lifecycle vibration conditions during design and qualification testing in the lab is the
re-creation of simultaneous multi-axial excitation that a product experiences in the field. Instead, the common practice is to use sequential single-axis
excitation in different axes or uncontrolled multi-axial vibration on repetitive shock shakers.
Consequently, the dominant failure modes in the field are sometimes very difficult to duplicate in a laboratory test.
Find out more in the
full article. You may also be interested in
Harmonic and Random Vibration Durability of SAC305 and Sn37Pb Solder Alloys and
Health Monitoring and Prognostics of Electronics Subject to Vibration Load Conditions
Please contact Prof. Abhijit Dasgupta for more information.
|
|
How Good Is Your Battery State of Health Estimation?
|
 |
|
State of Health Prediction with Dempster-Shafer Initialization
and Bayesian Monte Carlo Model Prediction |
|
CALCE has developed a new method for state of health (SOH) and remaining useful life (RUL) estimations for
lithium-ion batteries using Dempster–Shafer theory (DST) and the Bayesian Monte Carlo (BMC) method. In this work, an
empirical model based on the physical degradation behavior of lithium-ion batteries is developed. Model parameters
are initialized by combining sets of training data based on DST. BMC is then used to update the model parameters and
predict the RUL based on available data through battery capacity monitoring. As more data become available,
the accuracy of the model in predicting RUL improves.
To learn more about this study,
please click here.
If you found this article interesting, you may be interested in
Disassembly methodology for conducting failure analysis on lithium–ion batteries and
Prognostics of Lithium-ion Batteries using Extended Kalman Filtering.
For more information related to battery research at CALCE,
contact Dr. Michael Osterman.
|
|
Dr. Osterman to Discuss Solder Interconnect Reliability
in February Webinar |
| |
 |
| |
Fatigue Induced Solder Cracks |
Solder interconnects provide mechanical and electrical connection between packaged electronic devices and printed wiring boards
and are instrumental in the mass production of modern electronic equipment. In use, solder interconnects are subject to cyclic
loading due to handling, use, and operation. These cyclic loads result in microstructural changes that can lead to crack formation
and proprogation and ultimate failure. With a wider variety of solder materials being used due to regulations restricting the use of
traditionally used tin-lead eutectic solder, designers of electronic systems and personnel charged with ensuring the reliable operation of
electronic systems need to keep abreast of the latest information on solder interconnect reliability. In this web seminar,
Dr. Michael Osterman will examine the temperature cycling and mechanical cycling reliability of tin-silver-copper and tin-copper solders.
as well as the traditional tin-lead eutectic.
The web seminar will be held on February 21, 2012.
Click here or
contact Dr. Michael Osterman for more information.
|
|
Bhanu Sood to Hold IPC Short Course on Controlling Moisture Content in Boards: Best Practices |
 |
|
Mr. Bhanu Sood |
|
On February 26, 2012, Mr. Bhanu Sood will hold a
professional development course at the IPC APEX 2012 Conference to be held
at the San Diego Convention Center in San Diego, California. It is well known that the reliability of printed circuit board (PCB)
materials is strongly influenced by the presence of moisture. Moisture can be initially present in the epoxy glass prepreg, absorbed
during the wet processes in PCB manufacturing, or diffuse into the PCB during shipping or storage. Moisture can also reside in the
resin, resin/glass interfaces, and micro-cracks or voids due to defects. Higher reflow temperatures in lead-free processing can lead
to higher amounts of moisture uptake compared to eutectic tin-lead reflow processes. In addition to cohesive or adhesive failures
within the PCB that lead to cracking and delamination, moisture is also responsible for other failure mechanisms, such as
the creation of low impedance paths due to metal migration, interfacial degradation resulting in conductive anodic filaments (CAF),
changes in dimensional stability, reduction in the glass-transition temperature, and increases in the dielectric constant.
The professional development course will start with a refresher on PCB fabrication, followed by a review of
various moisture-related PCB failure mechanisms which will be illustrated with the help of case studies. Next, a discussion
of the moisture diffusion process will be presented, along with the governing diffusion models and dependent variables. The
course will then cover PCB handling, processing, and storage guidelines. These guidelines are classified based on distinct
steps during PCB manufacturing, assembly, storage, and shipping.
Please click here or
contact Bhanu Sood for more
details.
To register for the professional development
course please visit the IPC website
http://www.ipcapexexpo.org/html/main/register-now.htm.
|
|
Dr. Osterman to Hold IPC Short Course on Physics of Failure for Printed Circuit Board Assemblies
|
| |
 |
| |
Dr. Michael Osterman |
Dr. Michael Osterman
will conduct a short course on "Physics of Failure for Printed Circuit Boards" at the IPC APEX 2012 on February 26, 2012. Reliability is
the ability of a product to perform as intended (i.e., without failure and within specified performance limits) for a specified time, in its
life-cycle application environment. The physics-of-failure (PoF) approach to reliability utilizes knowledge of the life-cycle load profile,
product architecture, and material properties to identify potential failure mechanisms and reduce product failures through
robust design, manufacturing, and product verification practices. PoF-based product realization methods incorporate reliability
into the development process, providing a scientific basis for estimating product life under life-cycle conditions. This course
introduces the classic reliability concepts and relates them to the PoF approach. The information provided will be useful for implementing
a physics-of-failure methodology for the life cycle of a product, including product development. Participants will learn how to develop
and migrate to PoF-based reliability assessment programs from current practices.
Please click here or
contact Dr. Michael Osterman for more information.
To register for the professional development course please visit the IPC website
http://www.ipcapexexpo.org/html/main/register-now.htm.
|
|
CALCE Simulation Assisted Reliability Assessment (SARA ®)Training Course
|
| |
CalceSARA Time To Failure Map for Components on Printed Circuit Board
|
CALCE will provide a one day course on the calceSARA® software on March 19, 2012, at the
University of Maryland. This software includes virtual qualification capabilities for printed circuit boards and packaged semiconductors, as well as tin whisker risk
assessment for electronic devices. For printed circuit board analysis, the software includes a thermal analysis module to assess the operating temperatures of
the attached electronic devices as well as throughout the board; a mechanical analysis module to assess stress-induced by mechanical bending, vibration and
shock; and a life assessment module to determine the life expectancy of the assembly under test and field loading conditions. Participants in this course will
be provided with a six-month trial version of the software.
The course will be held at the College Park, MD campus of University of Maryland.
Please click here
or contact Michael Osterman for additional details.
|
|
CALCE Electronic Products and Systems Consortium Spring 2012 Technical Review
|
The CALCE Electronic Products and Systems Consortium (EPSC) will hold its semi-annual technical
review and project planning meetings on March 20-21, 2012 at the University of Maryland. At the review, CALCE researchers will present their latest finding on
research projects, including the role of sulfur concentration in corrosion failures of electronic equipment; the role of dust on surface insulation loss; the
reliability of electroless nickel, electroless palladium, and immersion gold (ENEPIG) as surface finishes for printed wiring boards; electrical requirements for
tin whisker induced arcing failures; as well as many others. A full list of CALCE EPSC research projects for 2012
can be found at:
http://www.calce.umd.edu/general/projects/current.
For organizations interested in joining the CALCE EPSC, this meeting will provide an excellent opportunity to learn about the current research program, meet and
network with CALCE EPSC members, and see firsthand some of the benefits afforded to CALCE EPSC members. Admission to this event is limited.
If you are interest in attending, please contact Michael Osterman.
|
|
Failure Analysis of Electronics Short Course
|
| |
Dendritic Growth found under Optical Inspection
|
| |
Delamination found through CSAM
|
An intensive 4-day course on “Failure Analysis of Electronics” is being offered jointly by CALCE and Buehler, April 17-20, 2012. The course, which covers
failure analysis techniques such as specimen preparation and materials analysis for electronic assemblies, components, and devices,
will consist of a combination of classroom instruction, demonstrations, and hands-on laboratory training. Lecture topics include
physics-of-failure-based root cause analysis, guidelines for selection of analytical tools, and practical instruction on laboratory
techniques. The laboratory segment of the course includes demonstrations and step-by-step sample preparation using metallographic techniques.
In addition, a number of case studies will be presented. These case studies will illustrate the step-by-step process of uncovering important pieces
of information that can lead to the isolation of a failure site and root cause determination.
The course will be held at the College Park campus of the University of Maryland. Please click here
(www.calce.umd.edu/facourse) or contact Bhanu Sood at 301-405-3498 or
by email at bpsood@calce.umd.edu for additional details.
|
|
The Center for Advanced Life Cycle Engineering (CALCE), the largest electronic products and systems research center focused on electronics reliability, is dedicated to providing a knowledge and resource base to support the development of competitive electronic components, products, and systems.
Unsubscribe from this list.
Our mailing address is:
inform@calce.umd.edu
Our telephone:
Tel.: 301-405-5323
Fax: 301-314-9269
Copyright (C) 2012 CALCE. All rights reserved.
|
|