Reliability and Mechanical Characterization and Analysis

National Laboratory: 
National Renewable Energy Laboratory
Characterization Class: 
Mechanical Behavior of Materials
Computational Tools Class: 

The National Renewable Energy Laboratory researches and investigates advanced thermomechanical and reliability aspects within multilayered structures, performing comprehensive evaluations via experimentation and modeling.

Capability Bounds: 

NREL focuses on the impacts of coefficients of thermal expansion mismatches between layers in a multilayered structure (e.g., a composite or layers of sheets) and the stresses induced in the layers when subjected to various forms of accelerated testing. These stresses can initiate and propagate defects in one or more layers and at interfaces between the layers. Materials characterization is done via numerous chambers for accelerated testing (temperature cycling, shock, and temperature elevation), accelerated stress test chambers, acoustic and digital microscopes for inspecting defects, profilometer for examining conditions of surfaces, bond and Instron mechanical testers, various forms of strength measurements and generation of stress-strain curves, hot-press, reflow station, and ovens for synthesis of bonded interfaces. Thermomechanical modeling, physics of failure, and predictive lifetime modeling also are performed.

Unique Aspects: 

NREL identifies failure mechanisms (via experimental characterization and modeling) caused by environmental conditions, such as thermal cycling, vibrations, and humidity, and operating conditions, including peaks/transients in the operating temperature. NREL also provides pathways to changing processing conditions to improve reliability.


All characterization tools and modeling capabilities are available. An NREL researcher will work with industry contacts to develop an appropriate accelerated testing plan for the prototype material or design. NREL researchers will complete testing and evaluation.

Single Point of Contact: 

Name: Douglas DeVoto
Phone: 303-275-4256

  1. D. DeVoto, P. Paret, M. Mihalic, S. Narumanchi, A. Bar-Cohen, and K. Matin. (2014). “Thermal Performance and Reliability Characterization of Bonded Interface Materials,” Proceedings of the 2014 IEEE ITherm Conference, Orlando, FL, May 2014.
  2. D. DeVoto, P. Paret, A. Wereszczak. (2014). “Stress Intensity of Delamination in a Sintered-Silver Interconnection.” High Temperature Electronics (HiTEC), May 2014, Albuquerque, NM.
  3. P. Paret, D. DeVoto, S. Narumanchi. (2015). “Reliability of Emerging Bonded Interface Materials for Large-Area Attachments.” Transactions on Components, Packaging and Manufacturing Technology. Accepted and in press.
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